Cholesterol-lowering benefits of oat-containing cereal in Hispanic americans. The hypocholesterolemic effects of beta-glucan in oatmeal and oat bran. A dose-controlled study. Serum lipid response to a fat-modified, oatmeal-enhanced diet. Do whole-grain oat cereals reduce the need for antihypertensive medications and improve blood pressure control? Oat ingestion reduces systolic and diastolic blood pressure in patients with mild or borderline hypertension: a pilot trial. Rye bread decreases serum total and LDL cholesterol in men with moderately elevated serum cholesterol. Effect of whole grains on insulin sensitivity in overweight hyperinsulinemic adults. Effects on serum lipids of adding instant oats to usual American diets.
This randomized, controlled trial of cholesterol lowering by an oat bran cereal containing beta glucan vs a corn cereal without soluble fiber in Hispanic Americans was conducted for 11 weeks. One-hundred fifty-two men and women, ages 30 to 70 years, with baseline low-density lipoprotein cholesterol (LDL-C) levels between 120 and 190 mg/dL and triglycerides <400 mg/dL were included. After eating a National Cholesterol Education Program Step 1 diet for 5 weeks, subjects were randomly assigned to the corn or the oat cereal for the next 6 weeks. The daily dose of beta glucan was 3 g. Consumption of oat cereal was associated with a reduction in plasma levels of both total cholesterol (-10.9+/-21.6 mg/dL; -4.5%) and LDL-C (-9.4+/-20.3 mg/dL; -5.3%). Consumption of corn cereal did not affect either total cholesterol (+1.2+/-18.3 mg/dL; 1.1%) or LDL-C (+1.2+/-17.5 mg/dL; 2.2%). Differences between the effects of the two cereals on total cholesterol and LDL-C were significant, P =.0003 and P =.0007, respectively. Oat cereals rich in the water-soluble fiber beta-glucan have been studied as a dietary therapy for hypercholesterolemia. To determine the hypocholesterolemic response of beta-glucan in the diet, 156 adults with low-density lipoprotein cholesterol (LDL-C) levels above 4.14 mmol/L (160 mg/dL) or between 3.37 and 4.14 mmol/L (130 and 160 mg/dL) with multiple risk factors were randomized to one of seven groups. Six groups received either oatmeal or oat bran at doses (dry weight) of 28 g (1 oz), 56 g (2 oz), and 84 g (3 oz). A seventh group received 28 g of farina (beta-glucan control). At week 6 of treatment, significant differences were found for both total cholesterol and LDL-C levels among the farina control and the treatment groups who were receiving 84 g of oatmeal, 56 g of oat bran, and 84 g of oat bran, with decreases in LDL-C levels of 10.1%, 15.9%, and 11.5%, respectively. Fifty-six grams of oat bran resulted in significantly greater reductions in LDL-C levels than 56 g of oatmeal. Nutrient analysis shows no difference in dietary fat content between these treatment groups; therefore, the higher beta-glucan content of oat bran most likely explains the significantly greater LDL-C reductions. A dose-dependent reduction in LDL-C levels with oat cereals supports the independent hypocholesterolemic effects of beta-glucan. The purpose of this study was to confirm and extend previous findings that serum cholesterol response to a fat-modified diet is enhanced by oat fiber. Participants (n = 236) were recruited from the Continental Illinois National Bank in Chicago. Data including weight, serum lipid level, lipoproteins, and 3-day food records were collected at baseline and every 4 weeks for 12 weeks. All participants were instructed to follow the fat-modified (Phase II) diet recommended by the American Heart Association (AHA). After 4 weeks, participants were randomly assigned to one of two groups. While both groups continued to follow the AHA diet, Group 1 was instructed to include 2 oz (56 g, dry wt) of oatmeal, isocalorically substituted for other carbohydrate foods. Group 2 served as the control and consumed no oat products throughout the study. Serum cholesterol values at baseline and after 4 weeks of the AHA diet were similar for both groups (203.9 and 193.0 mg/dl for Group 1 and 205.3 and 194.5 mg/dl for Group 2). After 4 weeks of oatmeal intervention, mean group differences were -6.8 and -2.1 mg/dl (P = 0.008 one-tailed t test) for Groups 1 and 2, respectively. Following an additional 4 weeks of oatmeal intervention, the Group 1 mean cholesterol increased slightly (0.9 mg/dl), while the Group 2 level decreased slightly (-0.7 mg/dl). Overall serum cholesterol responses for the two groups from Visit 2 to Visit 4 were -6.0 and -2.8 mg/dl for Groups 1 and 2, respectively (P = 0.074, one tail). Changes in weight were small and nonsignificant. Subgroup analyses revealed greater reductions in serum cholesterol among participants with the highest baseline serum cholesterol (-8.0 mg/dl vs -1.7 mg/dl for Subgroups 1 and 2, respectively). These data support previous findings that inclusion of oatmeal in a fat-modified diet is helpful in lowering serum cholesterol, particularly for individuals with elevated serum cholesterol levels. Our study compared 2 whole grain oat-based cereals with 2 refined grain wheat-based cereals to determine their effects on the need for antihypertensive medications in people with high blood pressure (BP).
                This 12-week, randomized controlled parallel-group trial with = 6 weeks of voluntary follow-up was designed to investigate the antihypertensive effects of oats. After 4 weeks of baseline feeding, medication dose was maintained or reduced by half or completely throughout the middle 4 weeks of the study. In the final 4 weeks, participants continued cereal consumption; medication was adjusted according to the protocol.
                Men and women (n = 88) being treated for hypertension with a mean baseline BP below 160/100.
                Primary study outcomes included change in SBP and DBP as well as antihypertensive medication reduction. Secondary measures included blood lipid, fasting glucose, and insulin levels and side effects related to elevated BP and increased dietary fiber intake.
                Seventy-three percent of participants in the oats group versus 42% in the control group were able to stop or reduce their medication by half. Treatment group participants whose medication was not reduced had substantial decreases in BP. The oats group experienced a 24.2-mg/dL reduction in total cholesterol levels, a 16.2-mg/dL decrease in low-density lipoprotein cholesterol levels, and a 15.03-mg/dL drop in plasma glucose levels vs controls.
                Results suggest that a diet containing soluble fiber-rich whole oats can significantly reduce the need for antihypertensive medication and improve BP control. Considering the lipid and glucose improvements as well, increased consumption of whole oats may significantly reduce cardiovascular disease risk. We assessed the short-term antihypertensive effects of soluble fiber-rich whole oat cereals when added to a standard American diet. In addition, multiple assessments of insulin sensitivity were conducted.
                This was a randomized, controlled, parallel-group pilot study designed to compare an oat cereal group (standardized to 5.52 g/day beta-glucan) to a low-fiber cereal control group (less than 1.0 g/day total fiber) over 6 weeks.
                A total of 18 hypertensive and hyperinsulinemic (= 10 U/mL or more) men and women completed the trial.
                Primary study outcomes were changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP). Secondary outcomes included blood lipid, fasting glucose, and insulin levels and side effects related to elevated blood pressure and increased dietary fiber intake.
                The oat cereal group experienced a 7.5 mm Hg reduction in SBP (P &lt.01) and a 5.5 mm Hg reduction in DBP (P &lt.02), while there was virtually no change in either SBP or DBP in the control group. In the oat cereal group, a trend was observed for a lower total insulin response to a glucose load, suggesting improved insulin sensitivity. However, this could not be confirmed using estimates from the Bergman Minimal Model, perhaps because of our small sample size. The oats group experienced a significant reduction in both total cholesterol (9%) and low-density lipoprotein cholesterol (14%).
                The addition of oat cereals to the normal diet of patients with hypertension significantly reduces both SBP and DBP. Soluble fiber-rich whole oats may be an effective dietary therapy in the prevention and adjunct treatment of hypertension. The objective of this study was to determine the hypocholesterolemic effects of whole meal rye and white wheat breads in healthy humans with elevated serum cholesterol concentrations, and the changes in plasma glucose and insulin concentrations during rye and wheat bread periods. The subjects were 18 men and 22 women with baseline serum cholesterol concentration of 6.4+/-0.2 mmol/L. The study design was a 2x4-wk crossover trial during which each subject randomly consumed rye and wheat breads (20% of daily energy) as part of their usual diet for 4 wk. The bread periods were separated by a 4-wk washout period. Blood samples (after fasting) were collected on two consecutive days at the beginning and end of the bread periods. Serum total cholesterol decreased by 8% (P = 0.002) in men but was not significantly altered in women during the rye bread period. The wheat bread period did not affect any of the variables studied. Analysis of the serum lipids in tertiles of rye bread consumption confirmed the reduction in total cholesterol (P = 0.048) in men and revealed the reduction in LDL cholesterol (P = 0.032); both were dependent on the amount of rye bread consumed (-2, -14 and -10% in total cholesterol and 0, -12 and -12% in LDL cholesterol). Neither rye nor wheat bread influenced the concentrations of glucose and insulin. In conclusion, rye bread is effective in reducing serum total and LDL cholesterol concentrations in men with elevated serum cholesterol. Good compliance with consuming a relatively large amount of rye bread in the usual diet indicates that rye bread offers a practical dietary means of reducing serum cholesterol in men. Epidemiologic studies have found whole-grain intake to be inversely associated with the risk of type 2 diabetes and heart disease.
                We tested the hypothesis that whole-grain consumption improves insulin sensitivity in overweight and obese adults.
                This controlled experiment compared insulin sensitivity between diets (55% carbohydrate, 30% fat) including 6-10 servings/d of breakfast cereal, bread, rice, pasta, muffins, cookies, and snacks of either whole or refined grains. Total energy needs were estimated to maintain body weight. Eleven overweight or obese [body mass index (in kg/m(2)): 27-36] hyperinsulinemic adults aged 25-56 y participated in a randomized crossover design. At the end of each 6-wk diet period, the subjects consumed 355 mL (12 oz) of a liquid mixed meal, and blood samples were taken over 2 h. The next day a euglycemic hyperinsulinemic clamp test was administered.
                Fasting insulin was 10% lower during consumption of the whole-grain than during consumption of the refined-grain diet (mean difference: -15 +/- 5.5 pmol/L; P = 0.03). After the whole-grain diet, the area under the 2-h insulin curve tended to be lower (-8832 pmol.min/L; 95% CI: -18720, 1062) than after the refined-grain diet. The rate of glucose infusion during the final 30 min of the clamp test was higher after the whole-grain diet (0.07 x 10(-4) mmol.kg(-1).min(-1) per pmol/L; 95% CI: 0.003 x 10(-4), 0.144 x 10(-4)).
                Insulin sensitivity may be an important mechanism whereby whole-grain foods reduce the risk of type 2 diabetes and heart disease. This study was designed as a test of the serum lipid response and dietary adaptation to recommended daily inclusion of instant oats in an otherwise regular diet. Hypercholesterolemic adults were randomly assigned to a control or intervention group. Participants in the intervention group were given packages of instant oats and requested to eat two servings per day (approximately two ounces dry weight), substituting the oats for other carbohydrate foods in order to maintain baseline calorie intake and keep weight stable. Serum lipids were measured in blood collected by venipuncture at baseline, four weeks, and eight weeks. Baseline mean total cholesterol (TC) levels were 6.56 mmol/L and 6.39 mmol/L for intervention and control groups, respectively. After eight weeks, mean serum total cholesterol of the intervention group was lower by -0.40 mmol/L, and mean net difference in TC between the two groups was 0.32 mmol/L (95% CI: 0.09, 0.54). Low-density lipoprotein-cholesterol was similarly reduced with mean net difference of 0.25 mmol/L (95% CI: 0.02, 0.48) between the two groups. Mean soluble fiber intake increased along with slight self-imposed reductions in mean total fat, saturated fat, and dietary cholesterol intake in the intervention group. Neither group changed mean body weight. Daily inclusion of two ounces of oats appeared to facilitate reduction of serum total cholesterol and LDL-C in these hyperlipidemic individuals.
Despite the consistency of effects seen in trials of wholegrain oats, the positive findings should be interpreted cautiously. Many of the trials identified were short term, of poor quality and had insufficient power. Most of the trials were funded by companies with commercial interests in wholegrains. There is a need for well-designed, adequately powered, longer term randomised controlled studies in this area. In particular there is a need for randomised controlled trials on wholegrain foods and diets other than oats.