Effectiveness of a low-fat vegetarian diet in altering serum lipids in healthy premenopausal women. A vegetarian diet rich in soybean products compromises iron status in young students. Effect of dietary alpha-linolenic acid on thrombotic risk factors in vegetarian men. Serum fatty acid, lipid profile and dietary intake of Hong Kong Chinese omnivores and vegetarians Plasma concentrations of 25-hydroxyvitamin D in meat eaters, fish eaters, vegetarians and vegans: results from the EPIC-Oxford study. Toward improved management of NIDDM: A randomized, controlled, pilot intervention using a lowfat, vegetarian diet. The selective lipid-lowering effect of vegetarianism on low density lipoproteins in a cross-over experiment. Vegetarian diet, change in dietary patterns, and diabetes risk: a prospective study Plasma lipids and lipoproteins in vegetarians and controls. The influence of maternal vegetarian diet on essential fatty acid status of the newborn. Cardiovascular disease risk factors in free-living men: comparison of two prudent diets, one based on lactoovovegetarianism and the other allowing lean meat. Vitamin B-12 supplementation improves arterial function in vegetarians with subnormal vitamin B-12 status A Vegetarian Diet Is a Major Determinant of Gut Microbiota Composition in Early Pregnancy
Few controlled trials have studied cholesterol-lowering diets in premenopausal women . None has examined the cholesterol-lowering effect of a low-fat vegetarian diet , which , in other population groups , leads to marked reductions in serum cholesterol concentrations and , in combination with other life-style changes , a regression of atherosclerosis . We tested the hypothesis that a low-fat , vegetarian diet significantly reduces serum total and low-density lipoprotein ( LDL ) cholesterol concentrations in premenopausal women . In a crossover design , 35 women , aged 22 to 48 , followed a low-fat vegetarian diet deriving approximately 10 % of energy from fat for 2 menstrual cycles . For 2 additional cycles , they followed their customary diet while also taking a " supplement " ( placebo ) pill .  Serum lipid concentrations were assessed at baseline and during each intervention phase . Mean serum LDL , high-density lipoprotein ( HDL ) , and total cholesterol concentrations decreased 16 . 9 % , 16.5 % , and 13.2 % , respectively , from baseline to the intervention diet phase ( p<0.001 ) , whereas mean serum triacylglycerol concentration increased 18.7 % ( p<0.01 ) . LDL/HDL ratio remained unchanged . Thus , in healthy premenopausal women , a low-fat vegetarian diet led to rapid and sizable reductions in serum total , LDL , and HDL cholesterol concentrations The iron status of young Chinese Buddhist vegetarians ( 23 men and 32 women ) and nonvegetarian students ( 20 men and 39 women from a medical college ) was investigated by dietary assessment of iron intake and hematological measurement of biochemical indices including hemoglobin , plasma iron , transferrin , transferrin saturation and plasma ferritin . A characteristic of the vegetarian diet in this study was the replacement of meat by soybean products . Results of the dietary assessment showed that the average iron density of the diets ranged from 1.9 to 2.2 mg/MJ , with no difference between the vegetarian and nonvegetarian diets . Daily iron intake was similar in both vegetarian and nonvegetarian men . However ,  iron intake was significantly higher in female vegetarians than nonvegetarians , averaging 104 and 78 % of the RDA , respectively . Results of blood analysis showed that , for both sexes , the median plasma ferritin concentration of the vegetarians ( male 47 micrograms/L and female 12 micrograms/L ) was about half the level of the nonvegetarians ( male 91 micrograms/L and female 27 micrograms/L ) . Occurrence and risk of iron deficiency are more prevalent in vegetarians . Correlation between plasma ferritin concentration and years of vegetarian practice in vegetarian men was marginally significant ( r = -0.38 , P = 0.077 ) . We conclude that a vegetarian diet that is rich in soybean products and restricted in animal foods is limited in bioavailable iron and is not adequate for maintaining iron balance in men and women BACKGROUND Vegetarians have lower platelet and plasma concentrations of n-3 polyunsaturated fatty acids ( PUFAs ) than do omnivores . We recently showed that male vegetarians have higher platelet aggregability than do omnivores . OBJECTIVE We investigated whether male vegetarians ( n = 17 ) who consumed an increased amount of dietary alpha-linolenic acid ( ALA )  showed any changes in their tissue profile of PUFAs , plasma thromboxane concentrations , platelet aggregability , or hemostatic factors . DESIGN During the study , all subjects maintained their habitual vegetarian diets except that a proportion of dietary fat was replaced with vegetable oils and margarines that were provided . Initially , all subjects consumed a low-ALA diet ( containing safflower oil and safflower oil-based margarine ) for 14 d ; they then consumed either a moderate-ALA diet ( containing canola oil and canola oil-based margarine ) or a high-ALA diet ( containing linseed oil and linseed oil-based margarine ) for 28 d. Blood sample s were collected at day 0 ( baseline ) , day 14 , and day 42 . RESULTS Eicosapentaenoic acid , docosapentaenoic acid , total n-3 PUFAs , and the ratio of n-3 to n-6 PUFAs were significantly increased ( P < 0.05 ) , whereas the ratio of arachidonic acid to eicosapentaenoic acid was decreased ( P < 0.05 ) , in platelet phospholipids , plasma phospholipids , and triacylglycerols after either the moderate-ALA or high-ALA diet compared with the low-ALA diet . No significant differences were observed in thrombotic risk factors . CONCLUSION ALA from vegetable oils ( canola and linseed ) has a beneficial effect on n-3 PUFA concentrations of platelet phospholipids and plasma lipids in vegetarian males Objective : To examine the serum fatty acid and lipid profiles and dietary intake of  Hong Kong Chinese omnivores and vegetarians  with respect to cardiovascular health . Design : R and om population survey stratified by age and sex . Subjects : One-hundred and ninety-four omnivore subjects ( 81 men , 113 women ) age 25–70 y , and 60 ovo-lacto-vegetarian adults ( 15 men , 45 women ) age 30–55 y. Measurements : Nutrient quantitation was by a food frequency method . Serum fatty acids were analysed by  gas chromatography , and serum lipid  by st and ard laboratory methods . Results : Compared with omnivores , vegetarians had higher serum concentrations of polyunsaturated ( PUFA ) and monosaturated fatty acids ( MUFA ) , and lower saturated fatty acids ( SFA ) , long chain omega-3 and trans fatty acids ( TFA ) . They also had lower serum cholesterol and higher apoA-I concentrations , but the LDL/HDL ratio was not different . The ratio of polyunsaturated to saturated fatty acids intake was higher in vegetarians . Compared with results from population s with higher incidences of coronary heart disease , while lower myristic and palmitic acid concentrations and higher eicosapentaneoic ( EPA ) and docosahexanoic acid ( DHA ) may partly account for the difference in incidence , linoleic acid concentration was higher . Although the Chinese vegetarian diet may be beneficial for heart health in that antioxidant and fibre intakes are higher and saturated fat lower , the low EPA and DHA due to omission from dietary source and suppressed formation by high linoleic acid level , and the presence of TFA in the diet , may exert an opposite effect . Conclusion : There are some favourable features in the serum fatty acid profile in the Hong Kong Chinese population with respect to cardiovascular health , but the consumption of TFA is of concern . The Chinese vegetarian diet also contains some adverse features . Sponsorship : This study is partly sponsored by the Hong Kong Health Services Research Grant . European Journal Of Clinical Nutrition ( 2000 ) 24 , OBJECTIVE Vegetarians and vegans exclude certain food sources of vitamin D from their diet , but it is not clear to what extent this affects plasma concentrations of 25-hydroxyvitamin D ( 25(OH)D ) . The objective was to investigate differences in vitamin D intake and plasma concentrations of 25(OH)D among meat eaters , fish eaters , vegetarians and vegans . DESIGN A cross-sectional analysis . SETTING United Kingdom . SUBJECTS Plasma 25(OH)D concentrations were measured in 2107 white men and women ( 1388 meat eaters , 210 fish eaters , 420 vegetarians and eighty-nine vegans ) aged 20 - 76 years from the European Prospect i ve Investigation into Cancer and Nutrition (EPIC)-Oxford cohort . RESULTS Plasma 25(OH)D concentrations reflected the degree of animal product exclusion and , hence , dietary intake of vitamin D ; meat eaters had the highest mean intake of vitamin D ( 3·1 ( 95 % CI 3·0 , 3·2 ) μg/d ) and mean plasma 25(OH)D concentrations ( 77·0 ( 95 % CI 75·4 , 78·8 ) nmol/l ) and vegans the lowest ( 0·7 ( 95 % CI 0·6 , 0·8 ) μg/d and 55·8 ( 95 % CI 51·0 , 61·0 ) nmol/l , respectively ) . The magnitude of difference in 25(OH)D concentrations between meat eaters and vegans was smaller ( 20 % ) among those participants who had a blood sample collected during the summer months ( July-September ) compared with the winter months ( 38 % ; January-March ) . The prevalence of low plasma concentrations of 25(OH)D ( < 25 nmol/l ) during the winter and spring ranged from < 1 % to 8 % across the diet groups . CONCLUSIONS Plasma 25(OH)D concentrations were lower in vegetarians and vegans than in meat and fish eaters ; diet is an important determinant of plasma 25(OH)D in this British population OBJECTIVE To investigate whether glycemic and lipid control in patients with non-insulin-dependent diabetes ( NIDDM ) can be significantly improved using a low-fat , vegetarian ( vegan ) diet in the absence of recommendations regarding exercise or other lifestyle changes . METHODS Eleven subjects with NIDDM recruited from the Georgetown University Medical Center or the local community were r and omly assigned to a low-fat vegan diet ( seven subjects ) or a conventional low-fat diet ( four subjects ) . Two additional subjects assigned to the control group failed to complete the study . The diets were not design ed to be isocaloric . Fasting serum glucose , body weight , medication use , and blood pressure were assessed at baseline and biweekly thereafter for 12 weeks . Serum lipids , glycosylated hemoglobin , urinary albumin , and dietary macronutrients were assessed at baseline and 12 weeks . RESULTS Although the sample was intentionally small in accordance with the pilot study design , the 28 % mean reduction in fasting serum glucose of the experimental group , from 10.7 to 7.75 mmol/L ( 195 to 141 mg/dl ) , was significantly greater than the 12 % decrease , from 9.86 to 8.64 mmol/L ( 179 to 157 mg/dl ) , for the control group ( P < 0.05 ) . The mean weight loss was 7.2 kg in the experimental group , compared to 3 . 8 kg for the control group ( P < 0.005 ) . Of six experimental group subjects on oral hypoglycemic agents , medication use was discontinued in one and reduced in three . Insulin was reduced in both experimental group patients on insulin . No patient in the control group reduced medication use . Differences between the diet groups in the reductions of serum cholesterol and 24-h microalbuminuria did not reach statistical significance ; however , high-density lipoprotein concentration fell more sharply ( 0.20 mmol/L ) in the experimental group than in the control group ( 0.02 mmol/L ) ( P < 0.05 ) . CONCLUSION The use of a low-fat , vegetarian diet in patients with NIDDM was associated with significant reductions in fasting serum glucose concentration and body weight in the absence of recommendations for exercise . A larger study is needed for confirmation In a cross-over experiment the effect of  short-term vegetarianism  on serum lipids , lipoproteins and apoproteins was studied . The experimental diet was free of animal products , with the exception of skim milk , and consequently low in saturated fat and cholesterol . Fifteen free-living individuals were r and omly assigned to 3-week periods on either the experimental diet or a control diet which closely approximated the usual intake in the U.S.A. Significant reductions in total cholesterol ( 12.5 % ) , low density lipoprotein cholesterol ( 14.7 % ) , and apo B ( 13.2 % ) were observed , accompanied by a non-significant decrease in high density lipoprotein cholesterol ( 10 % ) , apo A-I ( 3 % ) and a non-significant increase in apo-II ( 4 % ) . These data suggest that a fat-modified diet low in total fat , saturated fat and cholesterol , and moderate ( not high ) in polyunsaturated fat may not lower HDL-C or its apoproteins as much as a diet high in polyunsaturated fat , while having similar effects on LDL-C , and would therefore be preferable as the basis for primary prevention of atherosclerosis Background / objectives Vegetarian diets are inversely associated with diabetes in Westerners but their impact on Asians — whose pathophysiology differ from Westerners — is unknown . We aim to investigate the association between a vegetarian diet , change in dietary patterns and diabetes risk in a Taiwanese Buddhist population . Methods We prospect ively followed 2918 non-smoking , non-alcohol drinking Buddhists free of diabetes , cancer , and cardiovascular diseases at baseline , for a median of 5 years , with 183 incident diabetes cases confirmed .  Diet was assessed through a vali date d food frequency question naire at baseline and a simple question naire during follow-ups .  Incident cases of diabetes were ascertained through follow-up question naires , fasting glucose and HbA1C . Stratified Cox Proportional Hazards Regression was used to assess the effect of diets on risk of diabetes . Results Consistent vegetarian diet was associated with 35 % lower hazards ( HR : 0.65 , 95 % CI : 0.46 , 0.92 ) , while converting from a nonvegetarian to a vegetarian pattern was associated with 53 % lower hazards ( HR : 0.47 , 95 % CI : 0.30 , 0.71 ) for diabetes , comparing with nonvegetarians while adjusting for age , gender , education , physical activity , family history of diabetes , follow-up methods , use of lipid-lowering medications , and baseline BMI . Conclusion Vegetarian diet and converting to vegetarian diet may protect against diabetes independent of BMI among Taiwanese The possible effect of diet on plasma lipids was investigated in a group of vegetarians . Seventy-three men and 43 women who had adhered to a vegetarian diet for an average of three years were studied in the fasting state and compared with a r and omly selected group of controls matched for age and sex . Mean cholesterol levels in milligrams per deciliter for vegetarians and controls , respectively , were 126 and 184 ; low-density lipoprotein , 73 and 118 ; very-low-density lipoprotein , 11.8 and 17.2 ; high-density lipoproteins , 42 and 49 ; and mean triglyceride levels 59 and 86 . Mean weight and subscapular skinfold thicknesses were 58 kg and 6 mm for vegetarians and 73 kg and 17 mm for controls . Similar differences in lipid levels were found between subgroups of 42 vegetarians and controls with identical mean weights . Multiple regression analyses showed that consumption of dairy foods and eggs , but not body weight , was associated with the lipoprotein and cholesterol findings OBJECTIVES To evaluate whether a  maternal vegetarian diet influences the essential fatty acid status of the newborn and whether this is related to outcome of pregnancy . DESIGN  Dietary intake  and the fatty acid composition of plasma phospholipids were determined in 24 South Asian vegetarian and 24 white omnivore non-pregnant premenopausal women r and omly selected from the general population of North London . Umbilical cords and cord blood were collected at delivery from 48 South Asian vegetarian women and 98 white omnivores from the same catchment area along with details of antenatal history and the outcome of pregnancy . The fatty acid composition of the cord arteries and that of cord plasma phospholipids were analysed in a subset of 32 pairs of subjects , who were matched for maternal age , gestational age , parity and sex of infant . RESULTS Intakes of linoleic acid  ( 18:2n-6 ) expressed as proportion of the dietary energy and the ratio of linoleic to alpha-linolenic acid ( 18:3n-3 ) were higher in the vegetarian women , and eicosapentaenoic acid ( EPA , 20:5n-3 ) and docosahexaenoic acid ( DHA , 22:6n-3 ) were absent from their diets . The proportion of linoleic acid , as well as the absolute concentration , was greater and those of EPA and DHA were lower in plasma phospholipids , plasma free fatty acid and total plasma lipids of the vegetarians compared with the white subjects . The proportion of DHA was lower ( P > 0.001 ) but that of docosapentaenoic acid ( 22:5n-6 ) was greater ( P < 0.001 ) in cord those from the omnivores . The ratio of 20:3n-9/20:4n-6 was elevated in cord artery but not in cord plasma phospholipids in both groups . Early onset of labour and the duration of gestation was 5.6 days shorter . Birth weight , head circumference and length were lower in the infants born to South Asian vegetarians even after adjusting for maternal height , duration of gestation , parity , gender of infants and smoking habits . Multivariate analysis did not reveal any relationship between the proportions of DHA in plasma or cord artery phospholipids and the birthweight or head circumference of the infants . CONCLUSION This study demonstrates that vegetarians give birth to infants with less DHA in their plasma and cord artery phospholipids but this did not appear to be independently related to the outcome of pregnancy In general , vegetarians have lower serum lipids and blood pressures than omnivores have . We tested the blood pressure and serum lipid lowering effects of two fat-modified diets differing primarily in their source of protein . Twenty-six men were r and omized in an incomplete block design to two of three diets : a high-fat diet , a fat-modified lactoovovegetarian diet ( LOV ) and a diet in which 60 % of plant protein in the LOV was replaced with lean meat ( LM ) . Compared with the high-fat diet both prudent diets significantly lowered blood pressure , serum total cholesterol ( TC ) , and LDL cholesterol but significantly increased serum triglycerides . The LOV diet had a significantly greater cholesterol-lowering effect than did the LM diet ( 10 % vs 5 % decrease ) but blood pressure reductions were similar . The partial substitution of lean meat for plant protein in a fat-modified diet did not negate the overall cardiovascular-risk lowering of the lactoovovegetarian diet Objective Vegetarians are more vascular-healthy but those with subnormal vitamin B-12 status have impaired arterial endothelial function and increased intima-media thickness . We aim ed to study the impact of vitamin B-12 supplementation on these markers , in the vegetarians . Design Double-blind , placebo controlled , r and omised crossover study . Setting Community dwelling vegetarians . Participants Fifty healthy vegetarians ( vegetarian diet for at least 6 years ) were recruited . Intervention : Vitamin B-12 ( 500µg/day ) or identical placebo were given for 12 weeks with 10 weeks of placebo-washout before crossover ( n=43 ) , and then open label vitamin B-12 for additional 24 weeks (n=41).MeasurementHow-mediated dilation of brachial artery ( FMD ) and intima-media thickness ( IMT ) of carotid artery were measured by ultrasound . Results The mean age of the subjects was 45 + 9 years and 22 ( 44 % ) were male . Thirty-five subjects ( 70 % ) had serum B-12 levels < 150pmol/l . Vitamin B-12 supplementation significantly increased serum vitamin B-12 levels ( p<0.0001 ) and lowered plasma homocysteine ( p<0.05 ) . After vitamin B-12 supplementation but not placebo , significant improvement of brachial FMD ( 6.3±1.8 % to 6.9±1.9 % ; p<0.0001 ) and in carotid IMT ( 0.69±0.09 mm to 0.67±0.09 mm , p<0.05 ) were found , with further improvement in FMD ( to 7.4±1.7 % ; p<0.0001 ) and IMT ( to 0.65±0.09 mm ; p<0.001 ) after 24 weeks open label vitamin B-12 . There were no significant changes in blood pressures or lipid profiles . On multivariate analysis , changes in B-12 ( β=0.25 ; p=0.02 ) but not homocysteine were related to changes in FMD , ( R=0.32 ; F value=3.19 ; p=0.028 ) . Conclusions Vitamin B-12 supplementation improved arterial function in vegetarians with subnormal vitamin B-12 levels , proposing a novel strategy for atherosclerosis prevention The composition of the gut microbiota can be influenced by dietary composition . In pregnancy , the maternal gut microbiome has associations with maternal and infant metabolic status . There is little known regarding the impact of a vegetarian diet in pregnancy on maternal gut microbiota . This study explored the gut microbiota profile in women who were vegetarian or omnivorous in early gestation . Women were selected from participants in the Study of PRobiotics IN Gestational diabetes ( SPRING ) r and omised controlled trial . Nine women identified as vegetarians were matched to  omnivorous women in a 1:2 ratio . Microbiota analyses were performed using 16S rRNA gene amplicon sequencing and analysed using the Quantitative Insights Into Microbial Ecology ( QIIME ) and Calypso software tools . There was no difference in alpha diversity , but beta diversity was slightly reduced in vegetarians . There were differences seen in the relative abundance of several genera in those on a vegetarian diet , specifically a reduction in Collinsella , Holdemania , and increases in the relative abundances of Roseburia and Lachnospiraceae . In this sub- analysis of gut microbiota from women in early pregnancy , a vegetarian as compared to omnivorous diet , was associated with a different gut microbiome , with features suggesting alterations in fermentation end products from a mixed acid fermentation towards more acetate/butyrate
Conclusions This systematic review and meta‐ analysis provides evidence that vegetarian diets effectively lower blood concentrations of total cholesterol , low‐density lipoprotein cholesterol , high‐density lipoprotein cholesterol , and non – high‐density lipoprotein cholesterol .
Such diets could be a useful nonpharmaceutical means of managing dyslipidemia , especially hypercholesterolemia
Background Vegetarian diets exclude all animal flesh and are being widely adopted by an increasing number of people ; however , effects on blood lipid concentrations remain unclear .
This meta‐ analysis aim ed to quantitatively assess the overall effects of  vegetarian diets on blood lipids .