Marijuana is the most commonly used recreational drug worldwide (Battista et al., 2008). Marijuana contains various active components such as cannabinoids that act in both the central and the peripheral nervous system and that interfere with reproductive function at multiple levels. Cannabinoid receptors are located in multiple sites, including reproductive organs such as the ovary, the uterus, the vas deferens and the testis. Acute administration of marijuana in women reduces luteinizing hormone levels, whereas chronic use leads to tolerance and unchanged hormone levels (Park et al., 2004). Cannabinoids can affect fertilisation, oviductal transport and foetal and placental development by dysregulating signalling pathways involved in reproduction and by causing hormonal dysregulation (Battista et al., 2008, Rossato et al., 2008). The existing human data on illicit opiates and reproductive function in women are equivocal and inconclusive (Battista, Pasquariello et al., 2008). Cocaine has been shown to impair ovarian responsiveness to exogenous gonadotrophins in non-human primates and to adversely affect spermatogenesis in rodents (George et al., 1996, Thyer et al., 2001). Abnormal sexual function is common in heroinaddicted men and persists after withdrawal of heroin (Wang et al., 1978). Deterioration of all the sperm parameters, predominantly abnormal motility, have been demonstrated in the majority of heroin-addicted males and to a lesser extent in methadone users (Ragni et al., 1988, Ragni et al., 1985). Normal levels of serum gonadotrophins, with a significant elevation in prolactin and decrease in total and free testosterone levels, were reported in opiate-addicted men (Ragni et al., 1988, Ragni et al., 1985). The effects of cocaine and heroin use during pregnancy include placental disruption, pre-term delivery, low birth weight, neonatal mortality, neonatal withdrawal syndrome and possible long-term neurobehavioral effects, some of which can be associated with poor prenatal care and other substance use

rather than purely attributed to cocaine (Hulse et al., 1998, Richardson et al., 1993).

Couple experiencing infertility generally report that is a stressful experience (Anderson et al., 2010). The stress may arise from unfulfilled self-expectations, social pressure, undergoing evaluation and treatment, disappointment with failures and the financial costs associated with the whole process. Infertile women have a significantly higher prevalence of psychiatric disorders relative to fertile women (Chen et al., 2004). Infertile men appear to experience significant distress with transient episodes of impotence and sexual performance anxiety which may contribute to difficulties in achieving natural pregnancy (Peterson et al., 2007, Shindel et al., 2008). Psychological stress has been considered the most common reason for discontinuation of fertility treatment before achieving pregnancy (Olivius et al., 2004, Rajkhowa et al., 2006) and pre-treatment levels of depression have been shown to be highly predictive of patient dropout behavior after only one IVF cycle (Smeenk et al., 2004). Besides

mainly conducted in the form of animal studies (Anderson et al., 2010).

Despite spermatogenesis being a function of only the mature testis, environmental injury during maternal, perinatal and prepubertal phases can indirectly influence eventual sperm production in the adult male. It is believed that exposure during these phases of the developing testis leads to irreversible effects on spermatogenesis, while the accompanying effects of adulthood exposure are in all probability reversible (Dinulovic and Radonjic, 1990).

Evolution has caused our bodies to adapt to their environment. This connection is vital for reproduction as the birth of the young must coincide with plentiful food, and thus increase the chances of survival (Sharpe and Franks, 2002). Although human reproduction is not season specific, sexual behavior and reproduction is notable all year round. Fertility is influenced profoundly by our environment including season and food intake (Sharpe and Franks, 2002).

## **8. Treatments and solutions for the infertile DM patient: lifestyle changes**

Infertility is a global problem. It affects all socioeconomic levels, racial, ethnic and religious groups. Fortunately, in the majority of cases, there is a specific cause for infertility that can be medically resolved. In fact, only about 10% of infertility cases go unexplained.

When a couple seeks medical help, one of the first conditions the doctor will look for is diabetes since the condition can cause fertility complication in both genders. In most instances, simple lifestyle changes like adequate nutrition and weight loss through proper exercise can help reverse the effects of infertility (Figure 2). Fortunately, most cases of infertility, which are related to diabetes, can be treated. In cases where infertility is related to insulin levels, correcting the imbalance is often enough to result in a successful pregnancy. Normal levels of blood sugar are needed to succeed in becoming pregnant. This means insulin, HgbA1c and hemoglobin levels as well as weight need to be monitored. For Type 1 diabetes, insulin replacement therapy is the main treatment regime to be followed as prescribed by the treating physician. Furthermore, when a diabetic subject, exercises properly and ensuring adequate nutrition with a vitamin supplement the chances of conception are improved. Regular exercise helps weight loss and also aids the body in reducing blood glucose levels and in using insulin more efficiently. Newer approaches to treating infertility caused by diabetes and its complications include morbidly obese women undergoing bariatric or gastric bypass surgery (for weight loss). Preliminary successful results have been reported as diabetic women are now able to conceive as they lose weight.

Can Lifestyle Factors of Diabetes Mellitus Patients Affect Their Fertility? 109

Plessis et al., 2010). Once conception is achieved, the challenge is to control blood sugar levels so that the pregnancy can be carried to full term. The best way to prevent miscarriage in women with PCOS is to normalize hormone levels to improve ovulation, and normalize blood glucose and androgen levels. In recent time, more doctors have been prescribing the

Women who have a body mass index above 35 should lose weight before conception, and this should be an integral part of any fertility program's management of all overweight and obese patients. Weight loss of 5-10 per cent of total body weight can achieve a 30 per cent reduction of visceral adiposity, an improvement in insulin sensitivity, and may help with restoration of ovulation. More often than not, pharmacotherapy for fertility is needed in addition to all these lifestyle changes and thus, the expert management of a fertility

Women with Type 2 diabetes, there have shown a higher incidence of secondary hypogonadotropic amenorrhea (low sex hormones leading to absence of periods), exacerbated by body mass index that is low and glycosylated hemoglobin (HbA1c) that is higher than normal. In women with diabetes mellitus desiring pregnancy, pre-pregnancy counseling is essential before conception is critical to diminish the risk of spontaneous abortion, fetal abnormalities, macrosomia (abnormally big baby), and other pregnancy complications. Diabetic women should aim for a HbA1clevel of below 6 %, or below 7 % if

Other lifestyle changes or tips for helping fertility in diabetics include: avoiding cigarettes and any drugs that may affect sperm count or may reduce sexual function; getting sufficient rest and reducing stress; males must prevent overheating of the testes and should avoid hot baths, showers, and steam rooms, while avoiding tight underwear; and avoiding use of

If fertility issues remain unresolved, intrauterine insemination (also called artificial insemination) and assisted reproductive technologies, such as in vitro fertilization, may be

With careful management of this disorder, people can live long healthy lives and the effects

Diabetes mellitus can be either directly or indirectly associated with several disorders of the reproductive system and sexual function. Several studies have demonstrated that diabetes could be prevented by weight loss, regular exercise, modification of diet, abstinence from smoking, and limiting the consumption of alcohol. Weight control would appear to offer the greatest benefit. Education of diabetes is an important first step in order to make healthy

the risk of hypoglycemic episodes is too high, before pregnancy.

sexual lubricants, as they may affect sperm motility (Du Plessis et al., 2010).

drug metformin to help with this problem.

specialist is pivotal.

considered.

**9. Conclusion**

on fertility can be reduced notably.

lifestyle choices and manage the condition effectively.

**Figure 2.** Lifestyle modifications in the DM patient that can help improve fertility

Insulin resistance can be managed with modified diet, exercise, and drugs such as metformin. Exercise programs, vitamin supplements and weight loss alone will better ovulation in one-third of patients. When Clomiphene Citrate, Metformin and Letrozole are used to treat the remainder of infertility patients, more than 80% of infertile couples are able to conceive, as long as there are no other infertility problems reported. This benevolent effect is due to these lifestyle changes and adequate medical intervention in due time (Du Plessis et al., 2010). Once conception is achieved, the challenge is to control blood sugar levels so that the pregnancy can be carried to full term. The best way to prevent miscarriage in women with PCOS is to normalize hormone levels to improve ovulation, and normalize blood glucose and androgen levels. In recent time, more doctors have been prescribing the drug metformin to help with this problem.

Women who have a body mass index above 35 should lose weight before conception, and this should be an integral part of any fertility program's management of all overweight and obese patients. Weight loss of 5-10 per cent of total body weight can achieve a 30 per cent reduction of visceral adiposity, an improvement in insulin sensitivity, and may help with restoration of ovulation. More often than not, pharmacotherapy for fertility is needed in addition to all these lifestyle changes and thus, the expert management of a fertility specialist is pivotal.

Women with Type 2 diabetes, there have shown a higher incidence of secondary hypogonadotropic amenorrhea (low sex hormones leading to absence of periods), exacerbated by body mass index that is low and glycosylated hemoglobin (HbA1c) that is higher than normal. In women with diabetes mellitus desiring pregnancy, pre-pregnancy counseling is essential before conception is critical to diminish the risk of spontaneous abortion, fetal abnormalities, macrosomia (abnormally big baby), and other pregnancy complications. Diabetic women should aim for a HbA1clevel of below 6 %, or below 7 % if the risk of hypoglycemic episodes is too high, before pregnancy.

Other lifestyle changes or tips for helping fertility in diabetics include: avoiding cigarettes and any drugs that may affect sperm count or may reduce sexual function; getting sufficient rest and reducing stress; males must prevent overheating of the testes and should avoid hot baths, showers, and steam rooms, while avoiding tight underwear; and avoiding use of sexual lubricants, as they may affect sperm motility (Du Plessis et al., 2010).

If fertility issues remain unresolved, intrauterine insemination (also called artificial insemination) and assisted reproductive technologies, such as in vitro fertilization, may be considered.

With careful management of this disorder, people can live long healthy lives and the effects on fertility can be reduced notably.

## **9. Conclusion**

108 Diabetes Mellitus – Insights and Perspectives

**Figure 2.** Lifestyle modifications in the DM patient that can help improve fertility

Insulin resistance can be managed with modified diet, exercise, and drugs such as metformin. Exercise programs, vitamin supplements and weight loss alone will better ovulation in one-third of patients. When Clomiphene Citrate, Metformin and Letrozole are used to treat the remainder of infertility patients, more than 80% of infertile couples are able to conceive, as long as there are no other infertility problems reported. This benevolent effect is due to these lifestyle changes and adequate medical intervention in due time (Du Diabetes mellitus can be either directly or indirectly associated with several disorders of the reproductive system and sexual function. Several studies have demonstrated that diabetes could be prevented by weight loss, regular exercise, modification of diet, abstinence from smoking, and limiting the consumption of alcohol. Weight control would appear to offer the greatest benefit. Education of diabetes is an important first step in order to make healthy lifestyle choices and manage the condition effectively.

## **Author details**

Guillaume Aboua\* and Oluwafemi O. Oguntibeju *Department of Biomedical Sciences, Faculty of Health and Wellness, Cape Peninsula University of Technology, Bellville, South Africa*

Stefan S. du Plessis *Division of Medical Physiology, Faculty of Health Sciences, Stellenbosch University, Tygerberg, South Africa*

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**Chapter 7**

© 2013 Oguntibeju et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

and reproduction in any medium, provided the original work is properly cited.

**The Role of Fruit and Vegetable Consumption**

Several reports have shown that adequate intake of fruits and vegetables form an important part of a healthy diet and low fruit and vegetable intake constitute a risk factor for chronic diseases such as cancer, coronary heart disease (CHD), stroke and cataract formation (Van Duyn & Pivonka, 2000). Scientific evidence indicates that frequent consumption of fruits and vegetables can prevent oesophageal, stomach, pancreatic, bladder and cervical cancers and that a diet high in fruits and vegetables could prevent 20% of most types of cancers (Crawford *et al*., 1994). According to reports, fruit and vegetable consumption is influenced by gender, age, income, education and family origin (Wardle *et al*., 2000; Giskes *et al*., 2002). Other studies suggest that education may influence nutritional knowledge about fruits and vegetables and consequently also influence their intake. Empirical findings also indicate that family origin and socioeconomic status affect the purchasing power of food, food choice, food preparation and food availability which in turn affects consumption. Studies have shown that preferences of fruit and vegetable consumption differ in males and females (Wardle *et al*., 2000; Wang *et al*., 2002). A study carried out by Sylvestre *et al* (2006) revealed that mothers consumed 2 1/2 vegetable servings and 2 1/2 fruit servings on average daily and that the reported daily average of fruit and vegetable servings was slightly below the basic recommendation of 5 servings per day (Sylvestre *et al*., 2006). The same study suggested that children of mothers who consume high fruit and vegetable consumption are more likely to consume fruits and vegetables frequently than children of mothers with low fruit consumption. If the mothers with high fruit and vegetable consumption eat fruits and vegetables at home during meals which are shared with children, then their findings could underpin the importance of fruit and vegetable availability at home. However, it may be important to verify whether the relationship is simply a reflection of the control mothers have over food availability at home or it relates to shared nutritional knowledge about the

**in Human Health and Disease Prevention**

O. O. Oguntibeju, E. J. Truter and A. J. Esterhuyse

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/50109

benefits of fruits and vegetables.

**1. Introduction**

## **The Role of Fruit and Vegetable Consumption in Human Health and Disease Prevention**

O. O. Oguntibeju, E. J. Truter and A. J. Esterhuyse

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/50109

## **1. Introduction**

116 Diabetes Mellitus – Insights and Perspectives

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Tamer Erel, C., Senturk, L.M., 2009. The impact of body mass index on assisted

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Traish, A.M., Feeley, R.J., Guay, A., 2009. Mechanisms of obesity and related pathologies: androgen deficiency and endothelial dysfunction may be the link between obesity and

Tsai, E.C., Matsumoto, A.M., Fujimoto, W.Y., Boyko, E.J., 2004. Association of bioavailable, free, and total testosterone with insulin resistance: influence of sex hormone-binding

Vega, G.L., Adams-Huet, B., Peshock, R., Willett, D., Shah, B., Grundy, S.M., 2006. Influence of body fat content and distribution on variation in metabolic risk. J Clin Endocrinol

Walters, K.A., Allan, C.M., Handelsman, D.J., 2012. Rodent Models for Human Polycystic

Wang, C., Chan, V., Yeung, R.T., 1978. The effect of heroin addiction on pituitary-testicular

Wild, S., Roglic, G., Green, A., Sicree, R., King, H., 2004. Global prevalence of diabetes: estimates for the year 2000 and projections for 2030. Diabetes Care 27 (5), 1047-1053. Windham, G.C., Fenster, L., Swan, S.H., 1992. Moderate maternal and paternal alcohol consumption and the risk of spontaneous abortion. Epidemiology 3 (4), 364-370. Zaadstra, B.M., Seidell, J.C., Van Noord, P.A., te Velde, E.R., Habbema, J.D., Vrieswijk, B., Karbaat, J., 1993.  Curr Opin Obstet Gynecol 21 (3), 228-235.

Several reports have shown that adequate intake of fruits and vegetables form an important part of a healthy diet and low fruit and vegetable intake constitute a risk factor for chronic diseases such as cancer, coronary heart disease (CHD), stroke and cataract formation (Van Duyn & Pivonka, 2000). Scientific evidence indicates that frequent consumption of fruits and vegetables can prevent oesophageal, stomach, pancreatic, bladder and cervical cancers and that a diet high in fruits and vegetables could prevent 20% of most types of cancers (Crawford *et al*., 1994). According to reports, fruit and vegetable consumption is influenced by gender, age, income, education and family origin (Wardle *et al*., 2000; Giskes *et al*., 2002). Other studies suggest that education may influence nutritional knowledge about fruits and vegetables and consequently also influence their intake. Empirical findings also indicate that family origin and socioeconomic status affect the purchasing power of food, food choice, food preparation and food availability which in turn affects consumption. Studies have shown that preferences of fruit and vegetable consumption differ in males and females (Wardle *et al*., 2000; Wang *et al*., 2002). A study carried out by Sylvestre *et al* (2006) revealed that mothers consumed 2 1/2 vegetable servings and 2 1/2 fruit servings on average daily and that the reported daily average of fruit and vegetable servings was slightly below the basic recommendation of 5 servings per day (Sylvestre *et al*., 2006). The same study suggested that children of mothers who consume high fruit and vegetable consumption are more likely to consume fruits and vegetables frequently than children of mothers with low fruit consumption. If the mothers with high fruit and vegetable consumption eat fruits and vegetables at home during meals which are shared with children, then their findings could underpin the importance of fruit and vegetable availability at home. However, it may be important to verify whether the relationship is simply a reflection of the control mothers have over food availability at home or it relates to shared nutritional knowledge about the benefits of fruits and vegetables.

© 2013 Oguntibeju et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

#### **2. Fruits and vegetables as sources of vitamins, minerals and antioxidants**

The Role of Fruit and Vegetable Consumption in Human Health and Disease Prevention 119

and vegetables may be associated with a decreased incidence and mortality of a variety of chronic diseases which includes obesity. Fruit and vegetable intake has been shown to have positive effects in terms of weight management and obesity prevention (Tohill *et al*., 2004). Duncan *et al*. (1983) conducted a study using a diet rich in fruits and vegetables and low in fats versus a diet which was higher in fats but lower in fruits and vegetables. Although both groups were eating to satiety, the group eating the diet rich in fruits and vegetables consumed on average, one half the energy intake when compared to those on high fat, low fruit and vegetable diet. He *et* al. (2006) carried out a study in respect of fruit and vegetable consumption and its relationship to weight management. Their study found that an increase in fruit and vegetable intake was associated with a 24% lower risk of becoming obese.

In a large cohort of pre-adolescents and adolescents living in the USA, body mass index (BMI) changes were relatively consistent during a three year follow-up study. At the beginning of the study, more males than females were overweight and during the followup, change in body mass index (BMI) was slightly higher among the boys than in the girls. Among both genders, about 75% of the adolescents did not meet the public health recommendation to consume at least five servings of fruits and vegetables per/day (Field *et al*., 2003). There are various benefits gained by consuming a diet rich in fruits and vegetables, but it is not clearly understood why a diet rich in fruits and vegetables would prevent obesity or excessive weight gain, suggesting that further studies are needed to elucidate and confirm possible mechanisms involved in the prevention of obesity by fruit

Several cohort studies have examined the relationship between fruit and vegetable intake and coronary heart disease. These studies reported an inverse relationship between intake of fibre from fruits and vegetables and the risk of developing coronary heart disease. Metaanalyses of previous studies showed an inverse association between fruit and vegetable consumption and the occurrence of stroke which supports the concept that fruit and vegetable consumption has the potential to protect against cardiovascular events (Daucher *et al*., 2005; He *et al*., 2006). Daucher and co-workers (2006) carried out a meta-analyses of cohort studies and observed that the risk of developing coronary heart disease decreased by 4% for each additional portion per day intake of fruit and vegetables and by 7% for fruit consumption, indicating that fruit offer a more protective effect in reducing the risk of developing coronary heart disease (CHD). It has been observed that clinical and biological investigations support the protective effect offered by the intake of fruit and vegetables against coronary heart disease. Interestingly, the relationship is biologically valid with many clinical and laboratory data showing that the micro- and macro-constituents of fruit and vegetables improve important risk factors of CHD such as hypertension, dyslipidaemia and diabetes (Appel *et al*., 1997; Van Duyn *et al*., 2000; Bazzano *et al*., 2003). In different population studies, adequate fruit and vegetable intake have been shown to correlate with healthy lifestyles which may explain the lower CHD incidence rates among individuals who adequately consume fruits and vegetables. Generally, it is assumed that consumers of fruits and vegetables smoke less, exercise more and are better educated than non-consumers (Joshipura *et al*., 1999). Although many of the clinical and biological studies adjust for

and vegetable consumption.

Fruits and vegetables play an important role in human nutrition and health, particularly as sources of vitamin C, thiamine, niacin, pyridoxine, folic acid, minerals and dietary fibre (Wargovich, 2000). In the USA, the consumption of fruits and vegetables as a group is known to contribute to an estimated intake of 91% of vitamin C, 48% of vitamin A, 30% of folate, 27% of vitamin B6, 17% of thiamine and 15% of niacin. It is also known that fruit and vegetable intake supply 16% of magnesium, 19% of iron and 9% of the calories (United States Department of Agriculture, 2000). Other vital nutrients supplied by fruits and vegetables include riboflavin, zinc, calcium, potassium and phosphorus. Some components of fruits and vegetables (phytochemicals) are strong antioxidants and modify the metabolic activation and detoxification/disposition of carcinogens and may even influence processes that may change the course of the tumor cell (Wargovich, 2000). Although antioxidant capacity varies greatly among fruits and vegetables (Kalt, 2002), it is better to consume a variety of them rather than limiting consumption to a few with the highest antioxidant capacity. The United States Department of Agriculture (2000) encourages consumers to take at least two servings of fruits and at least three servings of vegetables per day, choose fresh, frozen, dried or canned forms of a variety of colours, kinds and choose dark-green leafy vegetables, orange fruits, vegetables and cooked dry beans and peas regularly. However, in some countries, consumers are encouraged to eat at least 10 servings of fruits and vegetables per day. There is evidence that consumption of whole foods is better than isolated food components such as dietary supplements and nutraceuticals. For instance, previous reports (Southon, 2000; Seifried *et al*. 2003) showed that increased consumption of carotenoid-rich fruits and vegetables offer a better protective effect than carotenoid dietary supplements by increasing LDL-oxidation resistance, lowering DNA damage and inducing higher repair activity in human volunteers who participated in a study conducted in European countries such as Italy and Spain. High consumption of tomatoes and tomato products have been associated with reduced carcinogenesis, especially of prostate cancer and is thought to be due to the presence of lycopene, which gives red tomatoes their colour (Giovannucci, 2002). Boileau *et al*. (2003) observed that the use of tomato powder significantly reduced prostate carcinogenesis in rats. Examples of fruits and vegetables recommended for daily consumption include spinach, orange, mango, carrot, melon, pineapples red grapefruit etc.

## **3. Fruit and vegetable consumption: Human health and disease prevention**

Childhood and adolescent obesity have reached epidemic proportions especially in the USA and the alarming rate at which this condition continues to increase is of great concern (Muriello *et al*., 2006). Unfortunately, obesity among children and adolescents is also increasing in South Africa and in other African countries due to western influence, and since behavior-related attitudes to obesity prevention such as physical activity and fruit and vegetable consumption tend to decline with age, it is important that intervention efforts begin early in life (Muriello *et al*., 2006). Research has shown that the consumption of fruits and vegetables may be associated with a decreased incidence and mortality of a variety of chronic diseases which includes obesity. Fruit and vegetable intake has been shown to have positive effects in terms of weight management and obesity prevention (Tohill *et al*., 2004). Duncan *et al*. (1983) conducted a study using a diet rich in fruits and vegetables and low in fats versus a diet which was higher in fats but lower in fruits and vegetables. Although both groups were eating to satiety, the group eating the diet rich in fruits and vegetables consumed on average, one half the energy intake when compared to those on high fat, low fruit and vegetable diet. He *et* al. (2006) carried out a study in respect of fruit and vegetable consumption and its relationship to weight management. Their study found that an increase in fruit and vegetable intake was associated with a 24% lower risk of becoming obese.

118 Diabetes Mellitus – Insights and Perspectives

**prevention**

**2. Fruits and vegetables as sources of vitamins, minerals and antioxidants**

Fruits and vegetables play an important role in human nutrition and health, particularly as sources of vitamin C, thiamine, niacin, pyridoxine, folic acid, minerals and dietary fibre (Wargovich, 2000). In the USA, the consumption of fruits and vegetables as a group is known to contribute to an estimated intake of 91% of vitamin C, 48% of vitamin A, 30% of folate, 27% of vitamin B6, 17% of thiamine and 15% of niacin. It is also known that fruit and vegetable intake supply 16% of magnesium, 19% of iron and 9% of the calories (United States Department of Agriculture, 2000). Other vital nutrients supplied by fruits and vegetables include riboflavin, zinc, calcium, potassium and phosphorus. Some components of fruits and vegetables (phytochemicals) are strong antioxidants and modify the metabolic activation and detoxification/disposition of carcinogens and may even influence processes that may change the course of the tumor cell (Wargovich, 2000). Although antioxidant capacity varies greatly among fruits and vegetables (Kalt, 2002), it is better to consume a variety of them rather than limiting consumption to a few with the highest antioxidant capacity. The United States Department of Agriculture (2000) encourages consumers to take at least two servings of fruits and at least three servings of vegetables per day, choose fresh, frozen, dried or canned forms of a variety of colours, kinds and choose dark-green leafy vegetables, orange fruits, vegetables and cooked dry beans and peas regularly. However, in some countries, consumers are encouraged to eat at least 10 servings of fruits and vegetables per day. There is evidence that consumption of whole foods is better than isolated food components such as dietary supplements and nutraceuticals. For instance, previous reports (Southon, 2000; Seifried *et al*. 2003) showed that increased consumption of carotenoid-rich fruits and vegetables offer a better protective effect than carotenoid dietary supplements by increasing LDL-oxidation resistance, lowering DNA damage and inducing higher repair activity in human volunteers who participated in a study conducted in European countries such as Italy and Spain. High consumption of tomatoes and tomato products have been associated with reduced carcinogenesis, especially of prostate cancer and is thought to be due to the presence of lycopene, which gives red tomatoes their colour (Giovannucci, 2002). Boileau *et al*. (2003) observed that the use of tomato powder significantly reduced prostate carcinogenesis in rats. Examples of fruits and vegetables recommended for daily consumption include spinach, orange, mango, carrot, melon, pineapples red grapefruit etc.

**3. Fruit and vegetable consumption: Human health and disease**

Childhood and adolescent obesity have reached epidemic proportions especially in the USA and the alarming rate at which this condition continues to increase is of great concern (Muriello *et al*., 2006). Unfortunately, obesity among children and adolescents is also increasing in South Africa and in other African countries due to western influence, and since behavior-related attitudes to obesity prevention such as physical activity and fruit and vegetable consumption tend to decline with age, it is important that intervention efforts begin early in life (Muriello *et al*., 2006). Research has shown that the consumption of fruits In a large cohort of pre-adolescents and adolescents living in the USA, body mass index (BMI) changes were relatively consistent during a three year follow-up study. At the beginning of the study, more males than females were overweight and during the followup, change in body mass index (BMI) was slightly higher among the boys than in the girls. Among both genders, about 75% of the adolescents did not meet the public health recommendation to consume at least five servings of fruits and vegetables per/day (Field *et al*., 2003). There are various benefits gained by consuming a diet rich in fruits and vegetables, but it is not clearly understood why a diet rich in fruits and vegetables would prevent obesity or excessive weight gain, suggesting that further studies are needed to elucidate and confirm possible mechanisms involved in the prevention of obesity by fruit and vegetable consumption.

Several cohort studies have examined the relationship between fruit and vegetable intake and coronary heart disease. These studies reported an inverse relationship between intake of fibre from fruits and vegetables and the risk of developing coronary heart disease. Metaanalyses of previous studies showed an inverse association between fruit and vegetable consumption and the occurrence of stroke which supports the concept that fruit and vegetable consumption has the potential to protect against cardiovascular events (Daucher *et al*., 2005; He *et al*., 2006). Daucher and co-workers (2006) carried out a meta-analyses of cohort studies and observed that the risk of developing coronary heart disease decreased by 4% for each additional portion per day intake of fruit and vegetables and by 7% for fruit consumption, indicating that fruit offer a more protective effect in reducing the risk of developing coronary heart disease (CHD). It has been observed that clinical and biological investigations support the protective effect offered by the intake of fruit and vegetables against coronary heart disease. Interestingly, the relationship is biologically valid with many clinical and laboratory data showing that the micro- and macro-constituents of fruit and vegetables improve important risk factors of CHD such as hypertension, dyslipidaemia and diabetes (Appel *et al*., 1997; Van Duyn *et al*., 2000; Bazzano *et al*., 2003). In different population studies, adequate fruit and vegetable intake have been shown to correlate with healthy lifestyles which may explain the lower CHD incidence rates among individuals who adequately consume fruits and vegetables. Generally, it is assumed that consumers of fruits and vegetables smoke less, exercise more and are better educated than non-consumers (Joshipura *et al*., 1999). Although many of the clinical and biological studies adjust for

lifestyle factors, basic confounders may still explain part of the favourable association with CHD. High fruit and vegetable intakes are related to a healthy diet pattern (Hu *et al*., 1999; Hu *et al*., 2000) and inversely associated with the consumption of saturated fat-rich food (Tucker *et al*., 2005), which may also contribute to a lower CHD risk (Hu *et al*., 1999; Hu *et al*., 2000; Fung *et al*., 2001). It should be noted however, that most of the clinical and laboratory studies to date have not established a causal relationship between inadequate consumption of fruits and vegetables and the risk of developing CHD. Daucher *et al*. (2006) reported that in different observational studies selected for meta-analyses, the association between vegetable consumption and CHD risk was more pronounced for cardiovascular mortality than for incident CHD. They stated that the reason for the difference is not known but possible explanations may be related to publication bias since mortality studies have fewer outcomes than studies reporting incident CHD or that consumption of vegetables might have specific effects on mortality, a hypothesis that needs confirmation in cohorts with a large number of fatal outcomes. It is also possible that residual confounding factors such as measurement errors affected the association between fruit and /or vegetable intake and risk of developing CHD and differences in study types, including dietary assessment methods, the variety of fruits or vegetables investigated and the definition of the reference group may further explain the difference.

The Role of Fruit and Vegetable Consumption in Human Health and Disease Prevention 121

suggest that higher intakes of fruits and vegetables are associated with improved blood glucose control and lower risk of developing type-2 diabetes. In a cohort study of 10, 000 adults in the USA, the risk of developing type-2 diabetes over the next 20 years was about 20% lower in those who reported consumption of at least 5 servings per day of fruits and vegetables as compared to those who did not consume fruits and vegetables (Ford & Mokdad, 2001). In a prospective cohort study that followed over 40 000 USA women for an average of nine years, fruit and vegetable intake was not associated with the risk of developing type-2 diabetes, however higher intakes of green leafy and yellow vegetables were associated with a significant reduction in the risk of developing type-2 diabetes in overweight women (Liu *et al*., 2004). A cross-sectional study of over 6000 non-diabetic adults in the UK, who consume higher volumes of fruits and vegetables showed to exhibit significantly low levels of glycosylated haemoglobin and it is postulated that potential compounds in fruits and vegetables that may enhance glucose control include fibre and

Dietary factors are estimated to account for about 30% of cancers in developed countries, making diet second only to tobacco smoking as a preventable cause of all cancer. This contribution of diet to the incidence of cancer is estimated to be about 20% in developing countries but it may decrease with fruit and vegetable consumption (WHO, 2008). Evidence from case-control and cohort studies has indicated that the intake of fruits and vegetables have a strong protective effect against various types of cancer (oropharynx, oesophagus, stomach, colon and rectum) and that people with a higher intake may have less risk than people with low or very low fruit and vegetable intake (Block *et al*., 1992; Steinmetz & Jansen, 1996). Van't Veer and co-workers (2000) indicated that people with higher intakes of fruits and vegetables could reduce their risk of developing cancer by 19%. The association between fruit and vegetable intake and the risk of cancer has been said to be relative to the quantities of fruits and vegetables consumed and that there are three potential doseresponse associations. It is anticipated that an extra serving of fruit and vegetables might achieve a much greater risk reduction when the total intake is relatively low than when it is high (a vitamin-like minimal requirement) or when the total intake is relatively high (a high threshold effect) and thirdly when intake is at all levels (not higher or lower) (Temple & Gladwin, 2003). With reference to the association between fruit and vegetable consumption, two cohort studies showed contrasting results. A study carried out by Terry *et al*. (2001) reported that fruit and vegetable intake could indicate a protective association only at intakes of about two servings per day whereas Mitchells *et al*. (2000) indicated that fewer than three servings of fruits and vegetables per week are not related to elevated risk of colorectal cancer. However, higher intakes of fruits and vegetables have been associated with a modestly significant reduction in lung cancer risk in a pooled analysis of eight prospective studies (Smith-Warner *et al*., 2003). Higher intakes of cruciferous vegetables have been linked to a significant reduction in the risk of developing bladder cancer in men (Micaud *et al*., 1999) and higher intakes of tomato products have been linked to a significant reduction in the risk of developing prostate cancer (Giovannucci *et al*., 2002). Joseph and coworkers (1999) indicated that supplementation of the diet of rats with fruits or vegetables

magnesium (Sargeant *et al*., 2001).

Ness and Powles (1997) reviewed evidence about fruit and vegetable intake and the development of coronary heart disease and found a significant inverse association between the amount of fruits and vegetables consumed and the incidence of coronary heart disease. Alonso *et al*. (2004) also reported a similar association between fruit and vegetable consumption and decreased blood pressure.

A study carried out by He *et al*. (2006) found a significant lower risk of stroke development among those with the highest intake of fruits and vegetables and Lock *et al* (2005) showed that increasing individual fruit and vegetable consumption by 600 grams per day could reduce the global burden of stroke by 19% and decrease the risk of CHD by 31% respectively.

High blood pressure increases the risk of heart disease and stroke (Chobanian *et al*., 2003). Adding more fruits and vegetables to a healthy diet is one possible pathway to reduce blood pressure. In the Dietary Approaches to Stop Hypertension (DASH) study (Appel *et al*., 1997), 459 people with and without high blood pressure were randomly assigned to one of three diets: a) a typical American diet that provided about 3 servings per day of fruits and vegetables and one serving per day of a low-fat dairy product, b) a fruit and vegetable diet that provided 8 servings per day of fruits and vegetables and one serving per day of a lowfat dairy product or c) a combination diet (called the DASH diet) that provided 9 servings per day of fruits and vegetables and 3 servings per day of low-fat dairy products. After 8 weeks, the blood pressures of those on the fruit and vegetable diet were significantly lower than those on the typical American diet.

It is believed that the evidence for a beneficial effect of a diet rich in fruits and vegetables on diabetes is not as convincing as it is for heart disease, however the results of a few studies suggest that higher intakes of fruits and vegetables are associated with improved blood glucose control and lower risk of developing type-2 diabetes. In a cohort study of 10, 000 adults in the USA, the risk of developing type-2 diabetes over the next 20 years was about 20% lower in those who reported consumption of at least 5 servings per day of fruits and vegetables as compared to those who did not consume fruits and vegetables (Ford & Mokdad, 2001). In a prospective cohort study that followed over 40 000 USA women for an average of nine years, fruit and vegetable intake was not associated with the risk of developing type-2 diabetes, however higher intakes of green leafy and yellow vegetables were associated with a significant reduction in the risk of developing type-2 diabetes in overweight women (Liu *et al*., 2004). A cross-sectional study of over 6000 non-diabetic adults in the UK, who consume higher volumes of fruits and vegetables showed to exhibit significantly low levels of glycosylated haemoglobin and it is postulated that potential compounds in fruits and vegetables that may enhance glucose control include fibre and magnesium (Sargeant *et al*., 2001).

120 Diabetes Mellitus – Insights and Perspectives

further explain the difference.

respectively.

consumption and decreased blood pressure.

than those on the typical American diet.

lifestyle factors, basic confounders may still explain part of the favourable association with CHD. High fruit and vegetable intakes are related to a healthy diet pattern (Hu *et al*., 1999; Hu *et al*., 2000) and inversely associated with the consumption of saturated fat-rich food (Tucker *et al*., 2005), which may also contribute to a lower CHD risk (Hu *et al*., 1999; Hu *et al*., 2000; Fung *et al*., 2001). It should be noted however, that most of the clinical and laboratory studies to date have not established a causal relationship between inadequate consumption of fruits and vegetables and the risk of developing CHD. Daucher *et al*. (2006) reported that in different observational studies selected for meta-analyses, the association between vegetable consumption and CHD risk was more pronounced for cardiovascular mortality than for incident CHD. They stated that the reason for the difference is not known but possible explanations may be related to publication bias since mortality studies have fewer outcomes than studies reporting incident CHD or that consumption of vegetables might have specific effects on mortality, a hypothesis that needs confirmation in cohorts with a large number of fatal outcomes. It is also possible that residual confounding factors such as measurement errors affected the association between fruit and /or vegetable intake and risk of developing CHD and differences in study types, including dietary assessment methods, the variety of fruits or vegetables investigated and the definition of the reference group may

Ness and Powles (1997) reviewed evidence about fruit and vegetable intake and the development of coronary heart disease and found a significant inverse association between the amount of fruits and vegetables consumed and the incidence of coronary heart disease. Alonso *et al*. (2004) also reported a similar association between fruit and vegetable

A study carried out by He *et al*. (2006) found a significant lower risk of stroke development among those with the highest intake of fruits and vegetables and Lock *et al* (2005) showed that increasing individual fruit and vegetable consumption by 600 grams per day could reduce the global burden of stroke by 19% and decrease the risk of CHD by 31%

High blood pressure increases the risk of heart disease and stroke (Chobanian *et al*., 2003). Adding more fruits and vegetables to a healthy diet is one possible pathway to reduce blood pressure. In the Dietary Approaches to Stop Hypertension (DASH) study (Appel *et al*., 1997), 459 people with and without high blood pressure were randomly assigned to one of three diets: a) a typical American diet that provided about 3 servings per day of fruits and vegetables and one serving per day of a low-fat dairy product, b) a fruit and vegetable diet that provided 8 servings per day of fruits and vegetables and one serving per day of a lowfat dairy product or c) a combination diet (called the DASH diet) that provided 9 servings per day of fruits and vegetables and 3 servings per day of low-fat dairy products. After 8 weeks, the blood pressures of those on the fruit and vegetable diet were significantly lower

It is believed that the evidence for a beneficial effect of a diet rich in fruits and vegetables on diabetes is not as convincing as it is for heart disease, however the results of a few studies Dietary factors are estimated to account for about 30% of cancers in developed countries, making diet second only to tobacco smoking as a preventable cause of all cancer. This contribution of diet to the incidence of cancer is estimated to be about 20% in developing countries but it may decrease with fruit and vegetable consumption (WHO, 2008). Evidence from case-control and cohort studies has indicated that the intake of fruits and vegetables have a strong protective effect against various types of cancer (oropharynx, oesophagus, stomach, colon and rectum) and that people with a higher intake may have less risk than people with low or very low fruit and vegetable intake (Block *et al*., 1992; Steinmetz & Jansen, 1996). Van't Veer and co-workers (2000) indicated that people with higher intakes of fruits and vegetables could reduce their risk of developing cancer by 19%. The association between fruit and vegetable intake and the risk of cancer has been said to be relative to the quantities of fruits and vegetables consumed and that there are three potential doseresponse associations. It is anticipated that an extra serving of fruit and vegetables might achieve a much greater risk reduction when the total intake is relatively low than when it is high (a vitamin-like minimal requirement) or when the total intake is relatively high (a high threshold effect) and thirdly when intake is at all levels (not higher or lower) (Temple & Gladwin, 2003). With reference to the association between fruit and vegetable consumption, two cohort studies showed contrasting results. A study carried out by Terry *et al*. (2001) reported that fruit and vegetable intake could indicate a protective association only at intakes of about two servings per day whereas Mitchells *et al*. (2000) indicated that fewer than three servings of fruits and vegetables per week are not related to elevated risk of colorectal cancer. However, higher intakes of fruits and vegetables have been associated with a modestly significant reduction in lung cancer risk in a pooled analysis of eight prospective studies (Smith-Warner *et al*., 2003). Higher intakes of cruciferous vegetables have been linked to a significant reduction in the risk of developing bladder cancer in men (Micaud *et al*., 1999) and higher intakes of tomato products have been linked to a significant reduction in the risk of developing prostate cancer (Giovannucci *et al*., 2002). Joseph and coworkers (1999) indicated that supplementation of the diet of rats with fruits or vegetables

(blueberry, strawberry or spinach) prevented or reversed age-related changes in neuronal and behavioural function. In our opinion, the finding of Joseph and coworkers is suggestive of a possible association between the mechanisms by which health may be modified by diet in both animal and man by the consumption of fruits and vegetables. A study carried by Galeone *et al*. (2007) showed that a high intake of fruits and vegetables significantly reduced the risk of lung cancer and that the reduced risk was significantly evident in smokers as well as non-smokers.

The Role of Fruit and Vegetable Consumption in Human Health and Disease Prevention 123

benefit of fruits and fruit juices is their ability to promote detoxification of the human body. Fruits help to cleanse the body and tomatoes, pineapples and citruses such as oranges, red grapefruits and lemons are well known for their detoxifying properties

Increased fruit and vegetable consumption of about 3 to 9 servings per day has been shown to decrease urinary calcium loss of about 50 mg/day and lower biochemical markers of bone

The effects of HIV infection on the nutritional status of persons living with HIV and AIDS have been reported (Oguntibeju *et al*., 2006; 2007; 2008; 2009). It is known that good nutrition including the consumption of fruits and vegetables can contribute to the wellness and sense of well-being of people living with HIV and AIDS and may even prolong life. Fruits and vegetables are an important part of a healthy food intake and may supply the necessary vitamins, minerals and other substances that could boost the immune system (Department

**4. Possible mechanism of action of fruits and vegetables in human health**

It is a common knowledge in biological science that mammalian and plant cells are constantly exposed to a variety of oxidizing agents. These oxidizing agents may be present in air, food, and water, or they may be produced by metabolic activity within the cells, however, it is important to maintain a balance between oxidants and antioxidants to be able to sustain optimal physiological conditions. Overproduction of oxidants can cause an imbalance, leading to oxidative stress (Ames *et al*., 1993; Adom *et al*., 2003). Oxidative stress can cause oxidative damage to macromolecules such as lipids, proteins and DNA and consequently lead to increased risk for developing chronic diseases such as cancer and cardiovascular disease (Ames *et al*., 1993; Liu *et al*., 1995). In order to prevent or reduce the oxidative stress induced by free radicals, sufficient amounts of antioxidants need to be consumed and fruits and vegetables are known to contain a variety of antioxidant compounds such as phenolics and carotenoids which may help protect cellular systems from oxidative damage and reduce the risk of developing chronic diseases (Wang *et al*., 1996; Vinson *et al*., 2001; Adom *et al*., 2003). It is known that carotenoids demonstrate photoprotection which originate from their ability to quench and inactivate reactive oxygen

Phenolics provide essential functions in the reproduction and the growth of plants; acting as defense mechanisms against pathogens, parasites, and predators as well as contributing to the colour of plants and may also provide health benefits associated with reduced risk of

Different species and varieties of fruits, vegetables, and grains have different phytochemical profiles (Adom & Liu, 2002; Adom *et al*., 2003) The combination of orange, apple, grape, and blueberry has been shown to display a synergistic effect in antioxidant activity and

turnover especially bone resorption (Appel *et al*., 1997; Lin *et al*., 2003).

(Cuthbertson, 2002).

of Health, South Africa, 2001).

**and disease prevention**

species (Britton, 1995).

chronic diseases in humans (Sun *et al*., 2002).

The incidence of cataracts has been reported to be related to oxidative damage of proteins in the eye's lens which is induced by long-term exposure to ultraviolet light. The cloudiness and discoloration of the lens resulting from such exposure have been known to lead to vision loss that becomes more severe with age. The results of various prospective cohort studies tend to suggest that diets rich in fruits and vegetables, particularly carotenoid and vitamin C-rich fruits and vegetables are associated with decreased incidence and severity of cataracts (Brown *et al*., 1999; Jacques *et al*., 2001; Christen *et al*., 2005). High intakes of broccoli and spinach have been reported to be associated to reduced cataracts among USA males (Brown *et al*., 1999).

Lutein and zeaxanthin are carotenoids that are found in relatively high concentrations in the retina and could play a role in preventing damage to the retina which is caused by light or oxidants (Mares-Perlman *et al*., 2002). In two reported case-control studies, high intakes of carotenoid-rich vegetables particularly those rich in lutein and zeaxanthin were said to be associated with a significant reduced risk of developing age-related macular degeneration (Seddon *et al*., 1994; Shellen *et al*., 2002). Another study involving more than 118 000 male and female participants found that those who consumed three or more servings of fruits and vegetables daily had their risk of developing age-related macular degeneration reduced by 36% than those participants who consumed less fruits and vegetables (Cho *et al*., 2004).

A beneficial association between reduced risk of developing chronic obstructive pulmonary disease and fruit and vegetable consumption has been documented (Romieu & Trenga, 2001). Epidemiological studies in Europe and elsewhere showed that higher fruit intake (particularly apple) can be associated with higher forced expiratory volume values, indicating a better lung function (Tabak *et al*., 2001; Butland *et al*., 2002). A European study of 2917 participants followed over twenty years with an increase in the daily consumption of fruits has been associated with a 24% decrease in the risk of death from chronic obstructive pulmonary disease. Although the reason for the association between increased fruit consumption and decreased risk of developing chronic obstructive pulmonary disease is not known but it is suggested that antioxidants such as vitamin C or flavonoids found in fruits may be playing a protective role in reducing the risk of developing chronic obstructive pulmonary disease.

Few studies have claimed that antioxidants found in most fruits and vegetable juices could help lower a person's risk of developing Alzheimer's disease. This may be related to the fact that freshly squeezed juices from fruits and vegetables are very good sources of minerals and vitamins which catalyze chemical reactions occurring in the body. Another benefit of fruits and fruit juices is their ability to promote detoxification of the human body. Fruits help to cleanse the body and tomatoes, pineapples and citruses such as oranges, red grapefruits and lemons are well known for their detoxifying properties (Cuthbertson, 2002).

122 Diabetes Mellitus – Insights and Perspectives

as non-smokers.

males (Brown *et al*., 1999).

pulmonary disease.

(blueberry, strawberry or spinach) prevented or reversed age-related changes in neuronal and behavioural function. In our opinion, the finding of Joseph and coworkers is suggestive of a possible association between the mechanisms by which health may be modified by diet in both animal and man by the consumption of fruits and vegetables. A study carried by Galeone *et al*. (2007) showed that a high intake of fruits and vegetables significantly reduced the risk of lung cancer and that the reduced risk was significantly evident in smokers as well

The incidence of cataracts has been reported to be related to oxidative damage of proteins in the eye's lens which is induced by long-term exposure to ultraviolet light. The cloudiness and discoloration of the lens resulting from such exposure have been known to lead to vision loss that becomes more severe with age. The results of various prospective cohort studies tend to suggest that diets rich in fruits and vegetables, particularly carotenoid and vitamin C-rich fruits and vegetables are associated with decreased incidence and severity of cataracts (Brown *et al*., 1999; Jacques *et al*., 2001; Christen *et al*., 2005). High intakes of broccoli and spinach have been reported to be associated to reduced cataracts among USA

Lutein and zeaxanthin are carotenoids that are found in relatively high concentrations in the retina and could play a role in preventing damage to the retina which is caused by light or oxidants (Mares-Perlman *et al*., 2002). In two reported case-control studies, high intakes of carotenoid-rich vegetables particularly those rich in lutein and zeaxanthin were said to be associated with a significant reduced risk of developing age-related macular degeneration (Seddon *et al*., 1994; Shellen *et al*., 2002). Another study involving more than 118 000 male and female participants found that those who consumed three or more servings of fruits and vegetables daily had their risk of developing age-related macular degeneration reduced by 36% than those participants who consumed less fruits and vegetables (Cho *et al*., 2004).

A beneficial association between reduced risk of developing chronic obstructive pulmonary disease and fruit and vegetable consumption has been documented (Romieu & Trenga, 2001). Epidemiological studies in Europe and elsewhere showed that higher fruit intake (particularly apple) can be associated with higher forced expiratory volume values, indicating a better lung function (Tabak *et al*., 2001; Butland *et al*., 2002). A European study of 2917 participants followed over twenty years with an increase in the daily consumption of fruits has been associated with a 24% decrease in the risk of death from chronic obstructive pulmonary disease. Although the reason for the association between increased fruit consumption and decreased risk of developing chronic obstructive pulmonary disease is not known but it is suggested that antioxidants such as vitamin C or flavonoids found in fruits may be playing a protective role in reducing the risk of developing chronic obstructive

Few studies have claimed that antioxidants found in most fruits and vegetable juices could help lower a person's risk of developing Alzheimer's disease. This may be related to the fact that freshly squeezed juices from fruits and vegetables are very good sources of minerals and vitamins which catalyze chemical reactions occurring in the body. Another Increased fruit and vegetable consumption of about 3 to 9 servings per day has been shown to decrease urinary calcium loss of about 50 mg/day and lower biochemical markers of bone turnover especially bone resorption (Appel *et al*., 1997; Lin *et al*., 2003).

The effects of HIV infection on the nutritional status of persons living with HIV and AIDS have been reported (Oguntibeju *et al*., 2006; 2007; 2008; 2009). It is known that good nutrition including the consumption of fruits and vegetables can contribute to the wellness and sense of well-being of people living with HIV and AIDS and may even prolong life. Fruits and vegetables are an important part of a healthy food intake and may supply the necessary vitamins, minerals and other substances that could boost the immune system (Department of Health, South Africa, 2001).

## **4. Possible mechanism of action of fruits and vegetables in human health and disease prevention**

It is a common knowledge in biological science that mammalian and plant cells are constantly exposed to a variety of oxidizing agents. These oxidizing agents may be present in air, food, and water, or they may be produced by metabolic activity within the cells, however, it is important to maintain a balance between oxidants and antioxidants to be able to sustain optimal physiological conditions. Overproduction of oxidants can cause an imbalance, leading to oxidative stress (Ames *et al*., 1993; Adom *et al*., 2003). Oxidative stress can cause oxidative damage to macromolecules such as lipids, proteins and DNA and consequently lead to increased risk for developing chronic diseases such as cancer and cardiovascular disease (Ames *et al*., 1993; Liu *et al*., 1995). In order to prevent or reduce the oxidative stress induced by free radicals, sufficient amounts of antioxidants need to be consumed and fruits and vegetables are known to contain a variety of antioxidant compounds such as phenolics and carotenoids which may help protect cellular systems from oxidative damage and reduce the risk of developing chronic diseases (Wang *et al*., 1996; Vinson *et al*., 2001; Adom *et al*., 2003). It is known that carotenoids demonstrate photoprotection which originate from their ability to quench and inactivate reactive oxygen species (Britton, 1995).

Phenolics provide essential functions in the reproduction and the growth of plants; acting as defense mechanisms against pathogens, parasites, and predators as well as contributing to the colour of plants and may also provide health benefits associated with reduced risk of chronic diseases in humans (Sun *et al*., 2002).

Different species and varieties of fruits, vegetables, and grains have different phytochemical profiles (Adom & Liu, 2002; Adom *et al*., 2003) The combination of orange, apple, grape, and blueberry has been shown to display a synergistic effect in antioxidant activity and

obtaining antioxidants from dietary intake by consuming a wide variety of foods is of significant importance due to the fact that foods originating from plants contain many diverse types of phytochemicals in various quantities.

The Role of Fruit and Vegetable Consumption in Human Health and Disease Prevention 125

versus low (10 to 15 oC) temperatures. In contrast, cool season crops such as broccoli, cabbage, spinach, peas produce more B vitamins at low versus high temperature. It has been reported that light intensity has little effect on the B vitamins but as light intensity increases, vitamin C increases and total carotenoids and chlorophyll decrease (Gross, 1991). Higher light intensities produce more sugars thus favouring the synthesis of vitamins and also increase plant temperatures, inhibiting beta-carotene production which protects chlorophyll from light bleaching. According to Goldman *et al*. (1999), the type of soil, the rootstock used for fruit trees, irrigation, fertilization and other traditional practices influence the water and nutrient supply to the plant and have been shown to affect the composition and quality attributes of fruits and vegetables. Other environmental factors such as altitudes, soil pH, salinity, insects and plant diseases have also been reported to affect composition and quality of fruits and vegetables. Also, processing and cooking methods do affect the nutritional value of fruits and vegetables (Lee & Kader, 2000). For example, water-soluble vitamins such as vitamin C and folic acid are readily lost at high rates when cooking water is

The level of education has been shown to be related to fruit and vegetable consumption in children and adults. It has been shown that mothers with a higher level of education tend to consume more fruits and vegetables and also influence their children to do so (Gibson, *et al*., 1998) and that higher income influences the availability of fruits, which in turn affect consumption in both adults and children. Family origin is said to influence food choice and preparation and one study indicated that the frequency of fruit and vegetable consumption in both mothers and children differs according to origin (Shatenstein &

For an adequate supply of vitamins, minerals and other compounds from fruits and vegetables, it is important to purchase fresh fruits and vegetables without bruises, soft spots, mold, decay or broken skins. It is very important to wash all fruits and vegetables before cutting, slicing and eating. It is also advisable to store fruit and vegetables in the refrigerator but once cut or sliced, fruits and vegetables should be placed in a refrigerator in tightly

There is a need for more controlled, clinical intervention trials in order to confirm findings that support the view that consumption of fruits and vegetables promotes health and reduces the risk of developing chronic diseases. Accurate assessment of dietary intake remains difficult and cost-efficient methods for estimating fruit and vegetable intake are needed to be able to confirm the relationship between fruit and vegetable consumption. Although research evidence supports the association between fruit and vegetable consumption and decreased incidence and mortality of chronic diseases such as obesity, different cancers and cardiovascular diseases, controversies still exist in the science community with reference to their association, therefore further studies with large

discarded.

Ghadirian, 1998).

**6. Recommendations and further studies**

sealed plastic bags and consumed within two to three days.

population groups over long periods of time is recommended.

Carcinogenesis is a multistep process, and oxidative damage is linked to the formation of tumors through several mechanisms (Ames *et al*., 1993; Liu *et al*., 1995). Oxidative stress induced by free radicals causes DNA damage, which, when left unrepaired, can lead to base mutation, single- and double-strand breaks, DNA cross-linking, and chromosomal breakage and rearrangement (Ames *et al*., 1993). This potentially cancer-inducing oxidative damage might be prevented or limited by the intake of dietary antioxidants which are found in fruits and vegetables. Studies to date have demonstrated that phytochemicals in common fruits and vegetables can have complementary and overlapping mechanisms of action, including antioxidant activity and the scavenging of free radicals, regulation of gene expression in cell proliferation, cell differentiation, oncogenes, and tumour suppressor genes, induction of cell-cycle arrest and apoptosis, modulation of enzyme activities in detoxification, oxidation, reduction, stimulation of the immune system, regulation of hormone metabolism, and antibacterial and antiviral effects (Ames *et al*., 1993; Liu *et al*., 1995; Adom & Liu, 2002).

It is believed that fruits and vegetables are rich in precursors to bicarbonate ions which serve to buffer acids in the body, therefore if the concentration of bicarbonate ions is inadequate to maintain normal pH, the body is capable of mobilizing alkaline calcium salts from bone in order to neutralize acids consumed in the diet and those generated by metabolism, thus increased consumption of fruits and vegetables reduces the net acid content of the diet and may preserve calcium in bones which might otherwise be mobilized to maintain normal pH (New, 2002).

The relationship between fruit and vegetable consumption and obesity has also been envisaged. It is not clear how fruit and vegetable consumption prevent obesity or excessive weight gain. However, one possible mechanism could be that fruits and vegetables might serve as healthy substitutes for more calorie-dense foods (Field *et al*., 2003).

## **5. Factors affecting the nutritional qualities and consumption of fruits and vegetables**

Climatic conditions such as temperature and light intensity have been shown to have a strong effect on the nutritional quality of fruits and vegetables (Mozafar, 1994). Low temperature is believed to favour synthesis of sugar and vitamin C while short duration decreases the rate of ascorbic acid oxidation. Maximum beta-carotene content in tomatoes occurs at a temperature range of 15 to 21oC but beta-carotene content is reduced if temperatures are higher or lower than this range, mainly due to the temperature sensitivity of lycopene, the precursor to beta-carotene and lutein.

The B vitamins are crop specific with reference to temperature sensitivity. Warm season crops (beans, tomatoes, peppers, melons) produce more B vitamins at high (27 to 30 oC versus low (10 to 15 oC) temperatures. In contrast, cool season crops such as broccoli, cabbage, spinach, peas produce more B vitamins at low versus high temperature. It has been reported that light intensity has little effect on the B vitamins but as light intensity increases, vitamin C increases and total carotenoids and chlorophyll decrease (Gross, 1991). Higher light intensities produce more sugars thus favouring the synthesis of vitamins and also increase plant temperatures, inhibiting beta-carotene production which protects chlorophyll from light bleaching. According to Goldman *et al*. (1999), the type of soil, the rootstock used for fruit trees, irrigation, fertilization and other traditional practices influence the water and nutrient supply to the plant and have been shown to affect the composition and quality attributes of fruits and vegetables. Other environmental factors such as altitudes, soil pH, salinity, insects and plant diseases have also been reported to affect composition and quality of fruits and vegetables. Also, processing and cooking methods do affect the nutritional value of fruits and vegetables (Lee & Kader, 2000). For example, water-soluble vitamins such as vitamin C and folic acid are readily lost at high rates when cooking water is discarded.

The level of education has been shown to be related to fruit and vegetable consumption in children and adults. It has been shown that mothers with a higher level of education tend to consume more fruits and vegetables and also influence their children to do so (Gibson, *et al*., 1998) and that higher income influences the availability of fruits, which in turn affect consumption in both adults and children. Family origin is said to influence food choice and preparation and one study indicated that the frequency of fruit and vegetable consumption in both mothers and children differs according to origin (Shatenstein & Ghadirian, 1998).

#### **6. Recommendations and further studies**

124 Diabetes Mellitus – Insights and Perspectives

Liu *et al*., 1995; Adom & Liu, 2002).

to maintain normal pH (New, 2002).

**and vegetables**

diverse types of phytochemicals in various quantities.

obtaining antioxidants from dietary intake by consuming a wide variety of foods is of significant importance due to the fact that foods originating from plants contain many

Carcinogenesis is a multistep process, and oxidative damage is linked to the formation of tumors through several mechanisms (Ames *et al*., 1993; Liu *et al*., 1995). Oxidative stress induced by free radicals causes DNA damage, which, when left unrepaired, can lead to base mutation, single- and double-strand breaks, DNA cross-linking, and chromosomal breakage and rearrangement (Ames *et al*., 1993). This potentially cancer-inducing oxidative damage might be prevented or limited by the intake of dietary antioxidants which are found in fruits and vegetables. Studies to date have demonstrated that phytochemicals in common fruits and vegetables can have complementary and overlapping mechanisms of action, including antioxidant activity and the scavenging of free radicals, regulation of gene expression in cell proliferation, cell differentiation, oncogenes, and tumour suppressor genes, induction of cell-cycle arrest and apoptosis, modulation of enzyme activities in detoxification, oxidation, reduction, stimulation of the immune system, regulation of hormone metabolism, and antibacterial and antiviral effects (Ames *et al*., 1993;

It is believed that fruits and vegetables are rich in precursors to bicarbonate ions which serve to buffer acids in the body, therefore if the concentration of bicarbonate ions is inadequate to maintain normal pH, the body is capable of mobilizing alkaline calcium salts from bone in order to neutralize acids consumed in the diet and those generated by metabolism, thus increased consumption of fruits and vegetables reduces the net acid content of the diet and may preserve calcium in bones which might otherwise be mobilized

The relationship between fruit and vegetable consumption and obesity has also been envisaged. It is not clear how fruit and vegetable consumption prevent obesity or excessive weight gain. However, one possible mechanism could be that fruits and vegetables might

**5. Factors affecting the nutritional qualities and consumption of fruits**

Climatic conditions such as temperature and light intensity have been shown to have a strong effect on the nutritional quality of fruits and vegetables (Mozafar, 1994). Low temperature is believed to favour synthesis of sugar and vitamin C while short duration decreases the rate of ascorbic acid oxidation. Maximum beta-carotene content in tomatoes occurs at a temperature range of 15 to 21oC but beta-carotene content is reduced if temperatures are higher or lower than this range, mainly due to the temperature sensitivity

The B vitamins are crop specific with reference to temperature sensitivity. Warm season crops (beans, tomatoes, peppers, melons) produce more B vitamins at high (27 to 30 oC

serve as healthy substitutes for more calorie-dense foods (Field *et al*., 2003).

of lycopene, the precursor to beta-carotene and lutein.

For an adequate supply of vitamins, minerals and other compounds from fruits and vegetables, it is important to purchase fresh fruits and vegetables without bruises, soft spots, mold, decay or broken skins. It is very important to wash all fruits and vegetables before cutting, slicing and eating. It is also advisable to store fruit and vegetables in the refrigerator but once cut or sliced, fruits and vegetables should be placed in a refrigerator in tightly sealed plastic bags and consumed within two to three days.

There is a need for more controlled, clinical intervention trials in order to confirm findings that support the view that consumption of fruits and vegetables promotes health and reduces the risk of developing chronic diseases. Accurate assessment of dietary intake remains difficult and cost-efficient methods for estimating fruit and vegetable intake are needed to be able to confirm the relationship between fruit and vegetable consumption. Although research evidence supports the association between fruit and vegetable consumption and decreased incidence and mortality of chronic diseases such as obesity, different cancers and cardiovascular diseases, controversies still exist in the science community with reference to their association, therefore further studies with large population groups over long periods of time is recommended.

#### **Author details**

O.O. Oguntibeju, E.J. Truter and A.J. Esterhuyse

*Oxidative Stress Research Centre, Department of Biomedical Sciences, Faculty of Health & Wellness Sciences, Cape Peninsula University of Technology, Bellville Campus, South Africa*

The Role of Fruit and Vegetable Consumption in Human Health and Disease Prevention 127

Crawford PB, Obarzanek E, Morrison J & Sabry ZI (1994). Comparative advantage of 3-day food records over 24 recall and 5-day food frequency validated by observation of 9-and

Cuthbertson WFJ (2002). Are the effects of dietary fruits and vegetables on human health related to those of chronic dietary restriction on animal longevity and disease? Brit J

Daucher L, Amouye P & Dallongeville J (2005). Fruit and vegetable consumption and risk of

Daucher L, Amouye P, Hercberg S & Dallongeville J (2006). Fruit and vegetable consumption and risk of coronary heart disease: a meta-analysis of cohort studies. J

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Field AE, Gillman MW, Rosnr B, Rockett HR & Colditz GA (2003). Association between fruit and vegetable intake and change in body mass index among a large sample of children

Ford ES & Mokdad AH (2001). Fruit and vegetable consumption and diabetes mellitus

Fung TT, Willett WC, Stampter MJ, Manson JE & Hu FB (2001). Dietary patterns and the risk

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*Oxidative Stress Research Centre, Department of Biomedical Sciences, Faculty of Health & Wellness*

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Alonso A, de la Fuente C, Martin-Arnau AM, de Irala J, Martinez JA & Gonzalez MA (2004). Fruit and vegetable consumption is inversely associated with blood pressure in a Mediterranean population with a high vegetable-fat intake. Brit J Nutr 92: 311-319. Ames BN, Shigenaga MK & Gold LS (1993). DNA lesions, inducible DNA repair and cell division: the three key factors in mutagenesis and carcinogenesis. Environ Health

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*Sciences, Cape Peninsula University of Technology, Bellville Campus, South Africa*

**Author details**

**7. References**

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**Chapter 8**

© 2013 Buowari, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

© 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

distribution, and reproduction in any medium, provided the original work is properly cited.

and reproduction in any medium, provided the original work is properly cited.

Diabetes mellitus is a growing public health affecting people worldwide both in developing and developed countries, and poses a major socio-economic challenge [1], [2]. A chronic metabolic disorder of multiple aetiologies is assuming epidemic proportions worldwide [3]. It is also a complex disorder with profound consequences both acute and chronic. Genetic and environmental factors play a role in the development of the disease [4]. The cells of the body cannot metabolise sugar properly due to a total or relative lack of insulin. The body then breaks down its own fat, protein, and glycogen to produce sugar resulting in high sugar levels in the blood with excess by products called ketones being produced by the liver [5]. Diabetes causes disease in many organ systems, the severity of which may be related to how long the disease has been present and how well it has been controlled. The term diabetes mellitus describes a metabolic disorder of multiple aetiology characterised by chronic hyperglycaemia with disturbances of carbohydrate, fat, and protein metabolism

Diabetes mellitus may present with characteristic symptoms such as thirst, polyuria, blurring of vision and weight loss [6]. The abnormalities of carbohydrate, fat, and protein metabolism are due to deficient action of insulin on target tissues resulting from

The effects of diabetes mellitus include long-term damage, dysfunction, and failure of various organs [6]. Type 1 diabetes mellitus encompasses the majority of diabetes, which are primarily due to pancreatic islet beta cell destruction and are prone to ketoacidosis [9]. If diabetes is not taken care of, complications such as heart, kidney, and eye diseases, incurable wounds leading to amputations of the extremities and mental disorders follow. Besides this, diabetes related complications inevitably cause high cost of treatment and opportunities for the concerned people and their families especially for poor families the

resulting from defects in insulin secretion, insulin action or both [6],[7],[8],[9].

**Diabetes Mellitus in Developing**

**Countries and Case Series**

Additional information is available at the end of the chapter

Omiepirisa Yvonne Buowari

http://dx.doi.org/10.5772/50658

insensitivity or lack of insulin [6].

**1. Introduction**

**Chapter 8**

## **Diabetes Mellitus in Developing Countries and Case Series**

Omiepirisa Yvonne Buowari

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/50658

## **1. Introduction**

130 Diabetes Mellitus – Insights and Perspectives

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Van Duyn MA & Pivonka E (2000). Overview of the health benefits of fruit and vegetable consumption for the dietetics professional. J Am Diet Assoc 99 (10): 1241-1248. Van't Veer P, Jansen MC, Klerk K & Kok FJ (2000). Fruits and vegetables in the prevention of

Vinson JA, Hao Y, Su X, Zubik L & Bose P (2001). Phenol antioxidant quantity and quality in

Wang H, Cao GH & Prior RL (1996). Total antioxidant capacity of fruits. J Agric Food Chem

Wang Y, Bentley ME, Zhai F & Popkin BM (2002). Tracking dietary intake patterns of Chinese from childhood to adolescence over a six-year follow-up period. J Nutr 132 93):

Wardle J, Permenter K & Waller J (2000). Nutrition knowledge and food intake. Appet 34

Wargovich MJ (2000). Anticancer properties of fruits and vegetables. Hort Sc 35: 573-575. WHO (2008). Population nutrient intake goals for preventing diet-related chronic diseases. Diabetes mellitus is a growing public health affecting people worldwide both in developing and developed countries, and poses a major socio-economic challenge [1], [2]. A chronic metabolic disorder of multiple aetiologies is assuming epidemic proportions worldwide [3]. It is also a complex disorder with profound consequences both acute and chronic. Genetic and environmental factors play a role in the development of the disease [4]. The cells of the body cannot metabolise sugar properly due to a total or relative lack of insulin. The body then breaks down its own fat, protein, and glycogen to produce sugar resulting in high sugar levels in the blood with excess by products called ketones being produced by the liver [5]. Diabetes causes disease in many organ systems, the severity of which may be related to how long the disease has been present and how well it has been controlled. The term diabetes mellitus describes a metabolic disorder of multiple aetiology characterised by chronic hyperglycaemia with disturbances of carbohydrate, fat, and protein metabolism resulting from defects in insulin secretion, insulin action or both [6],[7],[8],[9].

Diabetes mellitus may present with characteristic symptoms such as thirst, polyuria, blurring of vision and weight loss [6]. The abnormalities of carbohydrate, fat, and protein metabolism are due to deficient action of insulin on target tissues resulting from insensitivity or lack of insulin [6].

The effects of diabetes mellitus include long-term damage, dysfunction, and failure of various organs [6]. Type 1 diabetes mellitus encompasses the majority of diabetes, which are primarily due to pancreatic islet beta cell destruction and are prone to ketoacidosis [9]. If diabetes is not taken care of, complications such as heart, kidney, and eye diseases, incurable wounds leading to amputations of the extremities and mental disorders follow. Besides this, diabetes related complications inevitably cause high cost of treatment and opportunities for the concerned people and their families especially for poor families the

© 2013 Buowari, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

disease and its complications cause severe economical burden. In developing countries, noncommunicable diseases are evolving rapidly [8]. Diabetes mellitus places serious constraint on patients' activities [10]. Despite the high prevalence, serious long-term complications, and established evidence based guidelines for management of diabetes mellitus, the quality of care is still deficient in developing countries [11]. Diabetes mellitus is emerging as an epidemic all over the world, represents an important public health problem, and is of clinical concern [12], [13], [14]. Type 1 diabetes has been estimated to affect approximately 19,000 people in the worlds poorest countries but there is lack of good data on the disease prevalence in developing countries and in particular in sub-Saharan Africa[15].

Diabetes Mellitus in Developing Countries and Case Series 133

reduces the risk of complications yet studies from around the world concisely demonstrate

Sub-Saharan Africa will face a double disease burden represented by increased rates of noncommunicable diseases added to endemic, pandemic, and emergent infections such as malaria, tuberculosis, and HIV/AIDS. There is dearth of African data concerning the prevalence of type 1 diabetes mellitus [7]. Diabetes mellitus related cardiovascular disease complications are considered rare in Africa but are on the rise and are regularly associated with classic cardiovascular risk factors [24]. A missionary physician stated in 1901 that diabetes was very uncommon in the central region of Africa[25]. There is increased number of people suffering from non communicable diseases and this have been linked to unhealthy ways of living and lifestyle such as consumption of excess calories and reduction in the level of physical activities with the consequent development of obesity and insulin resistance [16]. Obesity, type 2 diabetes mellitus, and their associated long-term complications are emerging as critical, worldwide public health problems. Although few groups have been spared increased in the burden of these conditions, those undergoing rapid westernization, with the transition in diet and activity profiles have been especially affected. Among the most affected groups are those in Africa and the African Diaspora including the Caribbean, Europe, and North America [26]. The probably cause of obesity in developing countries has been attributed to the current lifestyle, where urbanization, better economic development and an increase in income have resulted in diet changes and less physical activity. The care for diabetic patients includes a change in their life style, where the diet plan represents an important pillar of care so they can meet their goals. Obesity increases the risk of developing not only type 2 diabetes, cardiovascular disease, stroke, osteoarthritis and some forms of cancer [27]. Obesity has been clearly linked with diabetic patients from all the major ethnic regions in Nigeria [16]. Over the past century, diabetes was considered a rare medical condition in Africa. However epidemiological studies carried out in the 90's have provided evidence of a different picture[28]. The number of people with diabetes is increasing due to population growth, aging, diet, lifestyle, urbanization, and increased prevalence of obesity and physical activity [12], [28], [29]. Diet and lifestyle are the biggest culprits at least in the case of type 2 diabetes but genetics also have a role to play. Although obesity is an important factor in the diabetes epidemic, it does not alone explain the vast increase in

In developing countries, the majority of individuals with diabetes are aged between 45 and 65 years while in developed countries, the majority are older than 64 years. Based on demographic changes by 2030, the number of people older than 64 years with diabetes will be more than 82 million in developing countries and more than 48 million in developed countries. The greatest relative increases are expected to occur in the Middle East crescent, sub-Saharan Africa and India [30]. Some 170 million men and women, who will reside in developing regions of the world in less than 30 years from now, will be suffering from

**2. Burden of diabetes mellitus in developing countries**

inappropriate variations in care [23].

prevalence especially in the developing world [29].

Non-communicable disease such as diabetes mellitus, cardiovascular disease (especially ischaemic heart diseases and hypertension), stroke, cancer and chronic kidney and respiratory diseases have become the leading causes of mortality both in developed and developing nations of the world. The rising prevalence of these diseases is thought to be due to adoption of western lifestyles and urbanization [16]. With the current trend of transition from communicable to non-communicable diseases, it is projected that the later will equal or even exceed the former in developing nations thus culminating in double burden [17]. There is need for health care providers to intensify efforts in educating people living with type 2 diabetes about good personal and environmental hygiene. Emphasis is on early diagnosis of diabetes, good glycaemic and blood control and proper education, programmes for health workers caring for diabetic patients as well as public awareness talks [17]. The prevalence of diabetes mellitus varies between different countries. Diabetes mellitus is defined as a chronic disorder, which is characterised by an elevated level of glucose in the blood due primarily in inadequate secretion or utilization of insulin [18].

Gestational diabetes mellitus is pregnancy induced diagnosed typically in the second half of pregnancy. It occurs when beta cells reserve is unable to counter balance the insulin resistance caused by placental hormone. Systemic hypertension and diabetes mellitus are common chronic conditions that frequently coexist and can significantly affect the health care needs and clinical outcome of affected individuals [19].

The excess global mortality attributable to diabetes in the year 2000 was estimated to be 2.9 million deaths, equivalent to 5.2% of all deaths. Excess mortality attributable to diabetes accounted for 2-3 % of deaths in poorest countries [20]. Diabetes is a serious illness with multiple complications and premature mortality accounting for at least 10 % of total health care expenditure in many countries. Diabetes is often perceived as a disease of affluent countries. A serious chronic disease leads to a substantial reduction in life expectancy, decreased quality of life and increased costs of care [21].

Management of diabetes mellitus is multidisciplinary and this is not readily available in low resource settings. Dietary management is essential in the treatment and it alone may be adequate to achieve and maintain the therapeutic goals to normoglycaemia and normolipidaemia [22]. The care for diabetic patients includes a change in their life style, where the diet plan represents an important pillar of care so they can meet their goals. The management of people with diabetes mellitus is complex and good control significantly reduces the risk of complications yet studies from around the world concisely demonstrate inappropriate variations in care [23].

### **2. Burden of diabetes mellitus in developing countries**

132 Diabetes Mellitus – Insights and Perspectives

disease and its complications cause severe economical burden. In developing countries, noncommunicable diseases are evolving rapidly [8]. Diabetes mellitus places serious constraint on patients' activities [10]. Despite the high prevalence, serious long-term complications, and established evidence based guidelines for management of diabetes mellitus, the quality of care is still deficient in developing countries [11]. Diabetes mellitus is emerging as an epidemic all over the world, represents an important public health problem, and is of clinical concern [12], [13], [14]. Type 1 diabetes has been estimated to affect approximately 19,000 people in the worlds poorest countries but there is lack of good data on the disease

Non-communicable disease such as diabetes mellitus, cardiovascular disease (especially ischaemic heart diseases and hypertension), stroke, cancer and chronic kidney and respiratory diseases have become the leading causes of mortality both in developed and developing nations of the world. The rising prevalence of these diseases is thought to be due to adoption of western lifestyles and urbanization [16]. With the current trend of transition from communicable to non-communicable diseases, it is projected that the later will equal or even exceed the former in developing nations thus culminating in double burden [17]. There is need for health care providers to intensify efforts in educating people living with type 2 diabetes about good personal and environmental hygiene. Emphasis is on early diagnosis of diabetes, good glycaemic and blood control and proper education, programmes for health workers caring for diabetic patients as well as public awareness talks [17]. The prevalence of diabetes mellitus varies between different countries. Diabetes mellitus is defined as a chronic disorder, which is characterised by an elevated level of glucose in the blood due

Gestational diabetes mellitus is pregnancy induced diagnosed typically in the second half of pregnancy. It occurs when beta cells reserve is unable to counter balance the insulin resistance caused by placental hormone. Systemic hypertension and diabetes mellitus are common chronic conditions that frequently coexist and can significantly affect the health

The excess global mortality attributable to diabetes in the year 2000 was estimated to be 2.9 million deaths, equivalent to 5.2% of all deaths. Excess mortality attributable to diabetes accounted for 2-3 % of deaths in poorest countries [20]. Diabetes is a serious illness with multiple complications and premature mortality accounting for at least 10 % of total health care expenditure in many countries. Diabetes is often perceived as a disease of affluent countries. A serious chronic disease leads to a substantial reduction in life expectancy,