Interaction of dietary sucrose and fiber on serum lipids in healthy young men fed high carbohydrate diets

High sucrose diets may cause increased serum triglycerides and decreased high density lipoprotein concentration. To determine whether dietary fiber protects against these effects, four groups of six healthy young men were assigned to one of four very high carbohydrate diets providing 0, 18, 36, or 52% of calories as sucrose. Each diet was fed in both low (less than 14 g) and high (greater than 34 g) levels of dietary fiber for 10 days each. Triglycerides increased during the 36 and 52% sucrose diets compared to 0 and 18% sucrose diets, and fiber protected partially against this rise. Serum cholesterol and LDL cholesterol were lower during the 0 and 18% sucrose diets than the 36 or 52% sucrose diets but fiber had no effect. HDL cholesterol decreased during all low fat diets, with a trend toward a greater decrease during the high sucrose diets. The results suggest that fiber protects against carbohydrate-induced lipemia but has no effect on cholesterol during very high carbohydrate diets.     

Lack of effect of dietary fiber on serum lipids, glucose, and insulin in healthy young men fed high starch diets

Eight healthy young men were fed a 72% carbohydrate high starch diet either high or low in dietary fiber for 4 days in a double cross-over design. Both groups showed a slight transient increase in plasma triglyceride level and a decrease in total and high-density lipoprotein cholesterol. There were few differences in glucose and insulin levels after glucose and meal tolerance tests after each diet. Fasting triglycerides and high-density lipoprotein cholesterol were inversely related at base-line; insulin response to oral glucose was inversely related to high-density lipoprotein cholesterol levels at the end of the study. We conclude that a high carbohydrate high starch diet, whether high or low in fiber, caused little increase in triglycerides, with little difference between the high and low fiber diets. Dietary fiber did not influence the fall in plasma cholesterol or high-density lipoprotein cholesterol concentrations over and above that seen after the low fiber diet.     

Effect of unsaturated fats and cholesterol on serum and fecal lipids. A study of healthy middle-aged men.

Modification of the Western diet, with an intake of 2,500 kcal per day and a decrease in cholesterol and fat intake to 33 per cent of calories with a P:S of 0.40, failed to alter serum lipids significantly. Evidence suggested that increasing the daily intake of cholesterol resulted in deposition in the body tissues. However, when the fatty acid composition and the P:S ratio of dietary fat were adjusted, lower serum lipids and a compensatory increase in fecal sterols occurred when cholesterol was added to the diet. Changes in serum lipoproteins in the subjects fed a "prudent" or a common diet indicate an increase in the proportion of HDL-cholesterol which may be beneficial in reducing coronary heart disease. Evidence suggests that, in absence of caloric excess, lowering of serum lipids and increased removal of fecal sterols is possible on a prudent diet without major modification of the customary foods, but that a high P:S ratio is required.     

Low dietary copper increases fecal free radical production,fecal water alkaline phosphatase activity and cytotoxicity in healthy men

One possible dietary factor that may increase susceptibility to colon cancer is inadequate copper intake. The objective of this study was to investigate the effects of low and adequate copper intakes on copper nutriture and putative risk factors for colon cancer susceptibility in healthy men. Seventeen healthy free-living nonsmoking men aged 21-52 y completed a 13-wk controlled feeding study in a randomized crossover design. The basal diet contained 0.59 mg Cu/13.65 MJ. After a 1-wk equilibration period in which the men consumed the basal diet supplemented with 1.0 mg Cu/d, they were randomly assigned to receive either the basal diet or the basal diet supplemented with 2 mg Cu/d for 6 wk. After the first dietary period, the men immediately began to consume the other level of Cu for the last 6 wk. They collected their feces during the equilibration period and during the last 2 wk of the two dietary periods for free radical and fecal water analysis. Low dietary copper significantly (P < 0.01) increased fecal free radical production and fecal water alkaline phosphatase activity. Low dietary copper significantly (P < 0.0001) decreased fecal water copper concentrations but did not affect fecal water volume, pH, iron or zinc concentrations. In contrast to the fecal analysis, hematological indicators of copper status were not significantly affected by the dietary treatments. These results suggest that low dietary copper adversely affects fecal free radical production and fecal water alkaline phosphatase activity, which are putative risk factors for colon cancer.     

输精管结扎对中老年男性脂类代谢及肝肾功能影响的研究

目的评估输精管结扎对中老年男性脂类代谢及肝肾功能的影响。方法对湖北省武汉市城区和江苏省南京市金湖县农村共2 352名中老年男性进行生殖健康现状调查,调查其输精管结扎情况并进行体格检查和血脂、肝肾功能指标及生殖激素检测。结果输精管结扎与总胆红素、直接胆红素、总蛋白、白蛋白及球蛋白相关(β=0.057、0.059、0.085、0.071、0.067,P0.01),结扎组人群上述指标数值低于未结扎组。输精管结扎与中老年男性脂类代谢、肝功能其他指标及肌酐、尿素均不相关(P0.05)。结论输精管结扎对中老年男性脂类代谢和肾功能无不良影响,但可能影响其总胆红素、直接胆红素和肝脏合成蛋白水平,有待进一步研究。     

Effect of wheat fiber on blood lipids, fecal steroid excretion and serum iron.

Adding 36 g of wheat fiber for 3 weeks to the metabolically controlled diets of six subjects produced a significant increase in daily fecal weight from 70.8 g +/- 6.2 SEM to 217 g +/- 12.1; serum iron also fell by 21 micrograms/100 ml +/- 2.1 SEM (P less than 0.001) during the added fiber period (measured in five subjects) as did mean corpuscular volume and mean corpuscular hemoglobin. Fecal neutral steroid concentration (measured in four subjects) fell from 31 to 17.3 mg/g dry weight (P less than 0.05) but the change in neutral steroid output and in acid steroid concentration and output was not significant. No change was seen in the serum levels of cholesterol and triglyceride.     

Effect of dietary fiber in insulin-dependent diabetics: insulin requirements and serum lipids

Four young adult (18 to 26 years old), nonobese human subjects (two men and two women) with insulin-dependent diabetes mellitus volunteered to consume a series of three diets: baseline (normal daily intake), wheat bran (normal daily intake + 78 gm wheat bran per day), and cellulose (normal daily intake + 30 gm cellulose per day). Wheat bran and cellulose diets both contained 60 gm dietary fiber, with 50% of the dietary fiber from wheat bran or cellulose, respectively. Each patient served as his or her own control. Randomized diets were of 6 weeks' duration, separated by a 4-week "recovery" period. At the conclusion of each diet, subjects were hospitalized and underwent 12 hours of computer-controlled, insulin-glucose infusions. Significant decreases were seen in fasting cholesterol (p less than .05), but the decreases seemed to result largely from the significant reductions in high-density lipoprotein cholesterol. A large reduction in triglycerides was noted with cellulose feeding but not with wheat bran. The mean daily insulin dose decreased (p less than .05) in response to fiber addition (8% and 10% decrease for wheat bran and cellulose feeding, respectively). Mean biostator insulin requirements decreased 11% with wheat bran (p less than .05) but not with cellulose. During biostator monitoring, subjects experienced delayed postprandial blood glucose and insulin-infusion rate peaks with both wheat bran and cellulose feeding. The wheat bran diet reduced peak blood glucose concentration and peak insulin infusion rate in comparison with baseline and cellulose diets. The data suggest that high levels of cellulose or wheat bran are of marginal benefit to insulin-dependent diabetic subjects.     

Dietary fiber and lifestyle influence serum lipids in free living adult men.

OBJECTIVE: The aim of this study was to determine the effect of dietary fiber consumption and lifestyle on serum lipids in adult men with non-restricted diet and physical activity. METHODS: Two groups of 19 men were classified as high (48 g/day) and low fiber groups (27 g/day). Anthropometry, food frequency, daily weighed intakes and physical activity were done for a seven-day period. Fasting blood was collected and serum was analyzed for triglycerides, total cholesterol and lipoprotein cholesterol fractions. RESULTS: Crude correlation coefficients showed that total cholesterol was negatively associated with physical activity, total dietary fiber and P/S ratio (r = 0.52; p < 0.001. r = -0.44; p < 0.01, r = 0.51, p < 0.001). LDL-C was also correlated negatively with total dietary fiber and P/S ratio (r = -0.34, p < 0.03; r = -0.53, p < 0.01). It was also positively associated with dietary cholesterol and body weight (r = 0.34, p < 0.03; r = 0.31, p < 0.05). Serum triglycerides had an inverse association with total dietary fiber and physical activity (r = -0.30: p < 0.05; r = -0.45, p < 0.004). After controlling for energy intake, total fat, saturated fat, dietary cholesterol, physical activity and body mass index, LDL-C/HDL-C, and TC/HDL-C, remained significantly associated with dietary fiber (r = 0.34; p < 0.05 and r = -0.38; p < 0.02, respectively). CONCLUSIONS: This study provides evidence in free living men that there is an association between dietary fiber intake and favorable lipid status and that lifestyle defined by socioeconomic status, physical activity and the quality of the dietary fat intake can play an important role. Public health nutrition advice and policy should continue to emphasize the importance of these factors.     

A randomized controlled trial of dietary fiber intake on serum lipids

OBJECTIVE: Clinical trials have indicated that water-soluble fiber from oats reduces serum cholesterol among hypercholesterolemic patients on a low-fat diet. We examined the effect of dietary fiber intake on serum lipids among persons without hypercholesterolemia. DESIGN: Randomized controlled trial. SETTING AND SUBJECTS: We recruited 110 participants who were aged 30-65 years and had a serum cholesterol level < 240 mg/dl from community. INTERVENTION: Study participants were randomly assigned to receive 8 g per day of water-soluble fiber from oat bran or a control intervention. RESULTS: At baseline, the mean levels of serum cholesterol and other measured variables were comparable between the high-fiber and control groups. Over the 3-month intervention, mean changes (95% confidence interval (CI)) in total, HDL-, and LDL-cholesterol were -2.42 mg/dl (-8.90 to 4.05 mg/dl; P = 0.46), -0.24 mg/dl (-2.19 to 1.71 mg/dl; P = 0.81), and -1.96 mg/dl (-7.32 to 3.40 mg/dl; P = 0.47) in the fiber group and -0.02 mg/dl (-5.29 to 5.26 mg/dl; P = 0.99), 1.42 mg/dl (-0.74 to 3.59 mg/dl; P = 0.19), and -0.64 mg/dl (-5.30 to 4.03 mg/dl; P = 0.79) in the control group, respectively. The net changes (95% confidence interval) in total, HDL-, and LDL-cholesterol were -2.40 mg/dl (-10.6 to 5.81 mg/dl; P = 0.56), -1.66 mg/dl (-4.55 to 1.22 mg/dl; P = 0.26) and -1.33 mg/dl (-8.33 to 5.68 mg/dl; P = 0.71), respectively. CONCLUSIONS: Our study does not support the hypothesis that water-soluble fiber intake from oat bran reduces total and LDL-cholesterol in study participants with a normal serum cholesterol level.     

Effects of dietary fiber, carbohydrate, lipid and protein levels on serum and liver lipids in rats

Response-surface regression analysis was used to study dietary levels of fiber, carbohydrate, lipid and protein to minimize serum and liver cholesterol and triglyceride levels and maximize serum high-density lipoprotein-cholesterol levels of male weanling rats. Because the dietary components were not statistically independent, they were studied in combinations of three variables. The three-variable combinations were the most useful in locating the desired maximum or minimum lipid responses in terms of the proportions of the dietary components. These analyses indicated that dietary carbohydrate, lipid and protein were better than dietary fiber for predicting the serum and liver lipid response levels. Response-surface contours and three-dimensional plots were developed for each lipid response except serum triglycerides, which were not predictable. The contours and three-dimensional plots were used to help determine those combinations of the diet components that would produce the desired maximum or minimum lipid responses. The statistical analyses indicated that the desired lipid response levels could be attained with a diet consisting of 3-5% neutral detergent bran fiber, 6-10% lipid, 54-55% carbohydrate, 26-30% protein and 4.7% vitamins and minerals.     

Influence of a fiber mixture on serum and liver lipids and on fecal fat excretion in rats

Male Sprague-Dawley rats (8 per group) were fed a modified AIN-76A diet containing either 10% cellulose or 10% of a proprietary fiber mixture for 21 days. Weight gain and liver weight were similar in the 2 groups but feed efficiency was higher in the test group. Serum cholesterol and triglycerides were lowered by 11% and 15%, respectively, by the test diet. Liver cholesterol was lowered significantly in the fiber-fed rats whereas liver triglycerides were elevated. Twenty-four–hour fecal collections were made on days 12 and 19. The weight of feces was unaffected by the test diet, but water content and fecal fat were increased by 27% and 44% and by 99% and 100%, respectively, on days 12 and 19. The amount of Liebermann-Burchard–positive material in the feces was significantly higher in rats fed the test material. The increases on days 12 and 19 were 139% and 105%, respectively.     

Socioeconomic differences in dietary patterns among middle-aged men and women

The aim of the study is to (i) identify common dietary patterns, (ii) study socioeconomic differences in these dietary patterns, and (iii) assess whether they contribute to socioeconomic differences in biological risk factors. The data come from the Whitehall II study of London civil servants, who participated in the third phase (1991-1993) and were 39-63-years old (N=8004). Food frequency questionnaire and socioeconomic background information was from a questionnaire, and biological risk factors from a medical screening. Six dietary patterns were identified. In reference to high employment grade men, the odds ratios of low grade men consuming the 'unhealthy' or the 'very unhealthy' diet were 1.26 and 3.34, respectively, while the odds for the 'French' diet was 0.13. Among women the corresponding odds were 2.98, 6.19 and 0.25. Adjusting for spouse's socioeconomic status and to a lesser extent smoking and exercise as well as job control attenuate these grade differences somewhat. Among men and women adjusting for dietary patterns accounted for about 25-50 per cent of grade differences in HDL and serum triglyceride levels.     

Dutch dietary guidelines: impact on blood lipids, blood pressure, body composition and urinary mineral excretion of Dutch middle-aged men

In this study the impact of the Dutch dietary guidelines diet on various health status parameters was examined. Twelve apparently healthy men aged 35-52 years were given both the guidelines diet (G) and the 'average' Dutch diet (D) in a controlled eight-week study period with a cross-over design. Compared with the D diet, the G diet contained less fat (accounting for 35 per cent vs 44 per cent of total energy intake), about half the amounts of saturated and monounsaturated fatty acids and twice the amount of polyunsaturated fatty acids. The G diet was given either as a high-sugar or as a low-sugar variant (25 per cent and 15 per cent of total daily energy intake, respectively). Serum total, LDL- and HDL-cholesterol decreased during the four-week G diet from 5.76 to 4.99, from 3.95 to 3.35 and from 1.13 to 1.03 mmol/l respectively. Also the apo-lipoprotein A-I, A-II and B concentrations decreased in subjects on the G diet. Blood pressure and body composition did not change significantly. Urinary pH and the excretion of sodium and potassium were significantly lower for the G diet. It is concluded that the combined factors in the Dutch guidelines diet, irrespective of amount of sugar, has favourable effects on total and LDL-cholesterol levels, whereas the decrease of the concentrations of HDL-cholesterol and of apo-A-I and A-II is less desirable. The changes in urinary mineral excretion, in particular of sodium, during the G-diet is considered as a positive effect.     

Effect of dietary fat and fiber on fecal flora, bacterial metabolites, and fecal properties in Japanese volunteers.

The effects of dietary fat and dietary fiber (DF) levels in diet on fecal flora, activities of three fecal enzymes, putrefactive metabolites, fecal mutagenicity and fecal properties were studied in eight healthy volunteers. They were given low fat and low DF diet (LF: fat energy ratio was 13.9%, and DF intake was 9.0 g/day) for 10 days, high fat and low DF diet (HF: fat energy ratio was 52.7%, and DF intake was 7.1 g/day) for 10 days, and high fat and high DF diet (HFF: fat energy ratio was 52.0%, and DF intake was 24.8 g/day) for 10 days. No change of fecal flora at the bacterial group level was observed throughout the experimental period, except that the population of lactobacilli showed a tendency to increase in HF period. Fecal activities of beta-glucuronidase, beta-glucosidase and nitroreductase and some putrefactive products were unchanged between LF and HF, while these values decreased in HFF period. No significant change of fecal properties was observed between LF and HF, while by HFF supplementation fecal weight increased and fecal pH value was lower than that in LF and HF. Excretions of iron, zinc and calcium in feces did not increase by high DF supplementation.     

Coffee consumption and serum aminotransferases in middle-aged Japanese men

We investigated the relation between coffee drinking and serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations among 7313 Japanese men receiving a health examination, excluding former alcohol drinkers and men with a history of chronic liver disease. Serum AST > 40 and/or ALT > 40 U/L was defined as liver inflammation. Adjustment was made for alcohol use, smoking, body mass index, serum marker for hepatitis virus infection, and other possible confounders. Adjusted odds ratios of liver inflammation were 1.00 (reference), 0.80, 0.69, and 0.61 for men drinking < 1, 1-2, 3-4, and > or = 5 cups of coffee daily, respectively. Among 6898 men without liver inflammation, serum AST and ALT were inversely associated with coffee consumption, and alcohol-related rise in AST was attenuated with coffee drinking. These findings suggest coffee may have an effect of suppressing the rise of serum aminotransferase, partly by inhibiting the alcohol-related elevation. Studies regarding biological mechanism are warranted.     

The effect of a natural high-fiber diet on serum lipids, fecal lipids, and colonic function.

In a cross-over experiment, 46 young healthy volunteers consumed in succession a high-fiber and a low-fiber diet for 3 weeks at two levels of dietary cholesterol. Half of the dietary fiber came from fruits and vegetables, and the rest from bread and other cereal products. On the high-fiber diet, concentrations of serum cholesterol decreased on average by 0.44 mmole/liter with high-cholesterol and 0.31 mmole/liter with low-cholesterol regimes; high density lipoprotein-cholesterole decreased by 0.1 mmole/liter; on average fecal weight increased by 115 g/day and mean transit time through the gut was decreased by 18 hr. Only part of the decrease in serum cholesterole may be due directly to the high intake of dietary fiber components. The remainder is due to differences in fat intake: during the high-fiber period subjects consumed less fat and cholesterol than had been planned.     

Endogenous cholesterol synthesis, fecal steroid excretion and serum lanosterol in subjects with high or low response of serum cholesterol to dietary cholesterol

In this study we addressed the question whether hypo- and hyper-responders to dietary cholesterol differ with regard to the flexibility of endogenous cholesterol synthesis after changes in cholesterol intake. Whole-body cholesterol synthesis was measured as faecal excretion of neutral steroids and bile acids minus cholesterol intake. In addition, we determined serum concentrations of lanosterol, a precursor of cholesterol and a possible indicator of cholesterol biosynthetic activity. The study was carried out with 2 hyper- and 4 hypo-responders; these subjects had shown a consistently high or low response of serum cholesterol to a decrease in dietary cholesterol in two previous experiments. The subjects received controlled high- (on average 697 mg of cholesterol per day) and low-cholesterol (109 mg/day) diets for periods of 4 weeks in succession; cholesterol was the only dietary variable. The two hyper-responders again showed a significant decrease in serum cholesterol. There was essentially no decrease in serum cholesterol in three of the four hypo-responders. The decrease in cholesterol intake caused an increase in cholesterol synthesis in five out of the six subjects. There was no association between the individual change in serum cholesterol and the change in cholesterol synthesis. Transfer from the high- to low-cholesterol diet caused an increase in serum lanosterol in all subjects. The increase was 3- to 4-fold higher in three out of the four hypo-responders than in the two hyper-responders. We tentatively suggest that this study provides some evidence that the flexibility of cholesterol synthesis is involved in the responsiveness to dietary cholesterol.     

Effects of dietary intake of soy protein and isoflavones on cardiovascular disease risk factors in high risk, middle-aged men in Scotland

OBJECTIVE: To investigate the effects of soy protein and isoflavones on blood pressure (BP) and cholesterol levels among high risk middle-aged Scottish men. DESIGN: A randomized, double-blind, placebo-controlled, parallel-group dietary intervention study SETTING: Inhabitants on Isles of Lewis and Harris in Scotland SUBJECTS: Sixty-one men with relatively higher BP and/or total cholesterol (TC) levels aged 45 to 59 went through the dietary intervention. INTERVENTION: Diets containing at least 20 g of soy protein and 80 mg of isoflavones were compared to the placebo diets. Intervention period was 5 weeks duration. RESULTS: Significant difference was found in 24-hour urinary isoflavone excretion between the two groups after intervention. Significant reductions from the baselines were observed in systolic BP (SBP) and diastolic BP (DBP), TC and non-high density lipoprotein cholesterol (non-HDL-C) in the soy-containing diet group, but not in the olive oil containing active placebo group. Significant increases in high density lipoprotein cholesterol (HDL-C) were observed in both groups. CONCLUSION: Dietary intakes of soy protein (at least 20 g) and isoflavones (at least 80 mg) for 5 weeks would be effective in reducing CHD risk among high-risk, middle-aged men.     

Dietary glycemic index, dietary glycemic load, and cardiovascular disease in middle-aged and older Swedish men

BACKGROUND: In women, dietary glycemic index (GI) and dietary glycemic load (GL) have been associated with cardiovascular disease; in men, however, the evidence for an association is weaker. OBJECTIVE: We tested the hypothesis that men consuming diets high in GI or GL have a greater risk of cardiovascular disease. DESIGN: At baseline, we assessed dietary GI and dietary GL by using food-frequency questionnaires in 36 246 Swedish men aged 45-79 y without diabetes or prior cardiovascular disease. Participants were followed through inpatient, cause-of-death, and death registries from 1 January 1998 until 31 December 2003 for myocardial infarction, ischemic stroke, hemorrhagic stroke, and cardiovascular mortality and until 31 December 2005 for all-cause mortality. We used Cox models with age as the time scale to estimate relative risks adjusted for cigarette smoking, body mass index, physical activity, demographic characteristics, and nutritional factors. RESULTS: Dietary GI and dietary GL were not associated with myocardial infarction (n = 1324), ischemic stroke (n = 692), cardiovascular mortality (n = 785), or all-cause mortality (n = 2959). Dietary GL was associated with hemorrhagic stroke [n = 165; relative risk = 1.44 comparing extreme quartiles (95% CI: 0.91, 2.27); P for trend = 0.047]. CONCLUSIONS: Dietary GI and dietary GL were not associated with ischemic cardiovascular disease or mortality, but dietary GL was associated with a greater risk of hemorrhagic stroke. Discrepancies between these findings and those of previous studies may be due to variations in the associations by sex or to differences in dietary contributions to GI and GL.