Changes in plasma cholesterol density distribution of young adult male rats fed a high fat and cholesterol diet following maternal cholestyramine treatment

The effects of feeding cholestyramine to pregnant rats, which has been shown to increase the fetal hepatic rate-limiting enzyme in cholesterol synthesis, HMG CoA reductase, on the plasma cholesterol density distribution was studied in the young adult male rat offspring before and after feeding a diet high in fat and cholesterol. As in previous studies, offspring of rats fed cholestyramine during pregnancy had a plasma total cholesterol level similar to controls when fed a low fat and cholesterol diet, but higher than controls when fed a 20% (wt/wt) fat plus 5% (wt/wt) cholesterol diet. Analyses of the plasma cholesterol density distribution by continuous gradient ultracentrifugation showed that, compared to control rats, rats born to dams fed cholestyramine had more cholesterol in the higher density regions of plasma before and after a 7-d high fat and cholesterol diet challenge. After a 4- or 7-d diet challenge, rats fed cholestyramine had 2-3 times more cholesterol in the d less than or equal to 1.006 g/ml range of plasma compared to the control offspring. The results suggest that long term changes in cholesterol metabolism due to early nutrition in the rat may include altered plasma or intestinal lipoprotein metabolism, rather than an effect specific to hepatic cholesterol synthesis.     

Oats and soy in lipid-lowering diets for women with hypercholesterolemia: is there synergy?

OBJECTIVES: To study possible synergistic effects of oats and soy on reducing total and low-density lipoprotein cholesterol (LDL-C) concentrations in human beings and the efficacy and feasibility of including these adjustments to a National Cholesterol Education Program Step I diet. SUBJECT/SETTING: One hundred twenty-seven postmenopausal women with moderate hypercholesterolemia were recruited from a large Midwestern workforce and senior centers in the surrounding community. Intervention and clinical visits were conducted in these same facilities. DESIGN: After a 3-week lead-in period on the Step I diet, participants were randomly assigned to 1 of 4 dietary treatments for an additional 6 weeks: an oats/milk group, a wheat/soy group, an oats/soy group, and a wheat/milk group. Clinical measurements included blood draws, body weight and height, blood pressure, and medical history data. Three-day food records were collected at baseline and Weeks 3 and 9 of the intervention. Randomization was stratified based on the status of hormone replacement therapy and was blocked with sizes 4 or 8 for group assignment. RESULTS: After 3 weeks on the Step I diet, total cholesterol, LDL-C, and triglyceride levels; total fat and saturated fat intake, dietary cholesterol intake, Keys score, and body mass index were all reduced. Following an additional 6 weeks on the Step I diet plus intervention, total cholesterol and LDL-C were further reduced for both the oats/soy group and oats/milk group. There were no significant further changes in total cholesterol, LDL-C, or high-density lipoprotein cholesterol levels in the wheat/soy and wheat/milk groups. Body mass index remained stable in all groups from Week 3 to Week 9. APPLICATIONS: Nonpharmacologic dietary interventions like the Step I diet are feasible in a community setting and can produce rapid and significant lipid-lowering benefits. Daily consumption of 2 servings of oats can contribute to further lipid alterations in this population although soy intake at this dose may not. Palatability and convenience are important considerations in achieving dietary adherence.     

The substitution of sucrose polyester for dietary fat in obese, hypercholesterolemic outpatients

Our aim was to determine the effects of the substitution of sucrose polyester (SPE) for dietary fat in a 16-week outpatient study in 36 obese subjects with primary hypercholesterolemia. The subjects were randomized into three groups who followed a 16-week treatment period where all subjects received hypocaloric diets which provided approximately 7 kcal/lb body weight, a polyunsaturated/saturated (P/S) fat ratio of 0.9, and 180 mg cholesterol/day. The percentages of calories as fat in the 3 groups were as follows: a low fat diet group (n = 12) received 27% of dietary calories as fat, a low fat plus SPE group (n = 13) received 25% of calories as fat plus 27 g SPE/day as a bread spread and salad dressing, and a third group (placebo, n = 11) received 37% of calories as fat with a 27 g/day conventional fat placebo (bread spread and salad dressing). Mean weight loss from baseline in the 16 week treatment period was 2.6, 3.9, and 3.4% respectively in the placebo, diet, and SPE groups, p less than .05 for each group, without significant differences between the groups. There was a mean reduction of low density lipoprotein cholesterol (LDL-C) of 16% in the SPE group (p less than .05), more than twice the reductions in the placebo and diet groups, 5% and 6%, respectively. There was a mean 20% reduction in the SPE group in triglyceride and very low density lipoprotein cholesterol (p less than .05), compared to 7 and 10% reductions in the placebo and diet groups respectively. The degree of weight loss was correlated with the degree of reduction in LDL-C in the low fat diet group, and in the low fat diet group plus SPE (r = 0.59 for both groups). Without confounding by different levels of dietary cholesterol or P/S, SPE induced significant reductions in LDL-C in hypercholesterolemic obese subjects beyond the effects of weight loss alone. The effects of SPE were significantly greater than those achieved by the use of a diet which severely limited conventional dietary fat intake (to 40 g/day). SPE in the form of a bread spread and a salad dressing is a practical formulation for outpatient hypocholesterolemic low fat diets and provides the lubricity and organoleptic benefits of authentic foods without the dense caloric content of digestible fats.     

Effect of diet during pregnancy and lactation on the activity of HMG-CoA reductase in the developing rat

Wistar rats were fed a control diet or a diet containing either cholestyramine or high fat and cholesterol throughout gestation and the first 14 d of lactation. New-born litters were cross-fostered from rats fed the control diet to rats fed either cholestyramine or high fat and cholesterol, or from rats fed cholestyramine to rats fed the control diet. Hepatic hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase activity, plasma cholesterol and triglycerides were assayed on gestation d 20 and postnatal d 8, 14, 22 and 30. Cholestyramine had no effect on maternal or fetal plasma lipid levels but increased fetal hepatic HMG-CoA reductase activity by approximately 50%. The increased reductase activity persisted on postnatal d 8 and 14. Control pups suckled by dams fed cholestyramine also had significantly increased HMG-CoA reductase activities on postnatal d 8 and 14. The high fat and cholesterol diet significantly increased maternal plasma cholesterol but had no effect on HMG-CoA reductase activity in the fetus or suckling pups. Neither cholestyramine nor high fat and cholesterol altered the rat milk cholesterol levels. The studies demonstrate that HMG-CoA reductase activity in the developing rat can be altered by factors dependent on maternal diet. They do not support a hypothesis for regulation by maternal dietary or milk cholesterol supply.     

Influence of maternal cholestyramine treatment on cholesterol and bile acid metabolism in adult offspring

To reduce ileal reabsorption of bile acids and to deplete hepatic cholesterol pools, female rats were fed a diet containing 5% (wt/wt) cholestyramine from 4 days prior to mating. Control rats were fed the same diet without cholestyramine. In one group on day 20 of gestation diet-fed dams and their fetuses were investigated. Additional pups were raised in litters of eight and nursed by their mothers for 30 days at which time they were weaned to the control diet. All dams were given the control diet from day 14 of lactation; at no time did neonates have access to cholestyramine. Offspring were raised until 3 months of age then fed the control, cholestyramine or a high fat, high cholesterol diet for 5 days. Maternal cholestyramine produced significant elevation of fetal hepatic 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase; fetal 7 alpha-hydroxylase (7 alpha-OH) activity, plasma cholesterol and triglyceride levels, however, were not significantly altered. The elevated HMG-CoA reductase activity persisted in liver and in addition was present in jejunum of 3-month-old male offspring challenged with the control or cholestyramine diet for 5 days. When challenged with the high fat, high cholesterol diet, male offspring from cholestyramine-treated dams had significantly higher plasma cholesterol levels but HMG-CoA reductase and 7 alpha-OH activity similar to controls. Maternal treatment had no apparent effect on plasma triglyceride or hepatic 7 alpha-OH in 3-month-old male offspring.(ABSTRACT TRUNCATED AT 250 WORDS)     

Trans fat intake lowers total cholesterol and high-density lipoprotein cholesterol levels without changing insulin sensitivity index in Wistar rats

Epidemiologic studies have demonstrated that trans fat intake increases the risk of some chronic diseases. We hypothesize that trans fat intake would increase the risk of cardiovascular disease and type 2 diabetes mellitus by changing the lipid profile in plasma, the secretion of adipokines in adipose tissue, and the insulin sensitivity. Accordingly, the major objective of present study was to investigate the effect of dietary intake of trans fat on lipid profile, insulin sensitivity, and adipokine levels in plasma. Two groups of Wistar rats were fed a diet containing 4.5% trans fat or a control diet containing no trans fat for 16 weeks. Fasting glucose level was monitored every 2 weeks. At the end of feeding experiment, blood, heart, kidney, liver, omental adipose tissue, and semitendinosus muscle were collected. The trans fat content in organs, lipid profile, adipokine, insulin, and glucose levels in plasma were analyzed. The trans fat content in adipose tissue, heart, kidney, liver, and muscle of rats fed trans fat were 169.9, 0.6, 1.2, 1.7, and 2.5 mg/g samples, respectively. The trans fat content in these organs contributed to 15.9%, 1.2%, 2.3%, 4.3%, and 6.1% of the total fat, respectively. The plasma glucose level, insulin level, and insulin sensitivity index were not significantly different between the trans fat and control groups. The results indicated that trans fat intake might not be related to insulin resistance. However, lipid profile and plasma adipokine levels were significantly changed after trans fat feeding. The trans fat fed group showed significantly lower total cholesterol and high-density lipoprotein cholesterol levels than the control group. The decreased high-density lipoprotein cholesterol level may indicate the detrimental effect of trans fat intake on lipid profile. Adiponectin and resistin levels were significantly higher in the trans fat group than the control group. Leptin levels were significantly lower in the trans fat group than the control group. The results indicated that dietary intake of trans fat can significantly change the adipokine levels, but the possible links between adipokine level change caused by trans fat intake and metabolic effects of this change need further investigations.     

广州市40~65岁中老年人膳食大豆异黄酮摄入与血脂关系的横断面研究

目的 研究广州市中老年人大豆异黄酮摄入与血脂的关系.方法 用食物频数问卷分析395名40～65岁广州市居民每日大豆异黄酮及其他食物和营养素的摄入量,抽取空腹静脉血测定血脂.结果 134名男性和261名女性的大豆异黄酮摄入分别为11.95(0～61.96)mg/d和14.90(0～82.52)mg/d.按照大豆异黄酮摄入量将研究对象等分为低、中、高三组,在校正了总能量摄入和脂肪供能比后,三组间TC、LDL-C差异有统计学意义(P值分别为0.002、0.008),并存在剂量效应关系(趋势分析P值分别为<0.001、0.012);高摄入组与低摄入组相比,TC、LDL-C分别下降7.06%、10.13%.在进一步校正年龄、BMI和腰臀比后,上述结果无明显改变.结论 膳食大豆异黄酮摄入与血浆TC、LDL-C负相关.     

The effect of taurine on the cholesterol metabolism in rats fed diets supplemented with cholestyramine or high amounts of bile acid

The effects of taurine on serum cholesterol levels and hepatic cholesterol 7alpha-hydroxylase activity (CYP7A1) were studied in rats fed cholestyramine or high amounts of sodium cholate in order to alter the intestinal pool of bile acids. Rats were fed a diet supplemented with 1% cholesterol and 0.25% sodium cholate (high cholesterol, control; C), and C supplemented with 4% cholestyramine (CH) or 0.75% sodium cholate (BA) for 14 d. Taurine groups were fed the diet supplemented with 3% taurine (CT, CHT and BAT). Compared to rats fed C and BA diets, serum cholesterol levels were significantly reduced in rats fed CT and BAT diets, but a significant reduction of serum cholesterol by taurine feeding was not observed in the CHT group as compared to the CH group. An increase in hepatic CYP7A1 activity due to taurine intake was observed in the CT and BAT groups. However, the simultaneous administration of cholestyramine and taurine (CHT group) did not increase hepatic CYP7A1 activity compared the intake of cholestyramine only (CH group). A significant increase in fecal bile acid excretion due to taurine intake was found only in rats fed the CT diet. In conclusion, it is suggested that taurine facilitates hepatic CYP7A1 activity regardless of the enlarged intestinal pool of bile acids due to increased intake of exogenous bile acid, and then reduces the serum cholesterol concentration.     

Food consumption scores and serum lipids levels in the population of São Paulo, Brazil

OBJECTIVE: To study food patterns assessed using scores of consumption and their relationship with serum total cholesterol (TOTAL-C), low density lipoprotein-cholesterol (LDL-C) and high density lipoproteins (HDL-C) concentration in the population of the metropolitan area of S?o Paulo, Brazil. METHODS: Data on food frequency consumption (FFC), serum lipids, and other covariates were available for a representative sample of 1,045 adults. A 12-month retrospective food frequency questionnaire was used. FFC was assessed using scores of consumption, which was obtained by grouping food according to their composition into two large groups: score I (known as risk food for cardiovascular diseases) and score II (known as healthy food). The association between the scores and serum blood lipoprotein levels among the study population was analyzed through multiple linear regression analyses. Modeling step-wise techniques were used to enter the covariates into the linear models. RESULTS: Increasing mean levels of TOTAL-C and LDL-C were seen from the lowest through the highest quintile of score I when compared to the score II, where decreasing mean levels of TOTAL-C and LDL-C were observed from the lowest to the highest quintile. The results of the linear regression analyses between serum TOTAL-C and LDL-C levels for both FFC score I and score II, after multivariate adjusting, showed a significant positive relationship with score I and a significant and inverse relationship with score II. CONCLUSIONS: In population studies, FFC analyses through scores can be the choice method to evaluate the quality of diet and its potential effect on serum levels of TOTAL-C and LDL-C.     

Soy protein and casein in cholesterol-enriched diets: effects on plasma lipoproteins in normolipidemic subjects

The effect of dietary plant protein vs animal protein on plasma lipoproteins was investigated in a crossover study. Eleven normal subjects consumed formula diets containing 20% of calories as soy protein or casein, 27% as fat, and 53% as carbohydrate: the average cholesterol intake was 500 mg/d. After an initial decrease in plasma cholesterol and low-density-lipoprotein cholesterol (LDL-C) on both diets, the concentration of LDL-C stabilized during the soy-protein diet at a 16% lower level than on the casein diet (p less than 0.02) whereas the concentration of high-density-lipoprotein cholesterol (HDL-C) was 16% higher (p less than 0.01). In a similar earlier study with a cholesterol intake of less than 100 mg/d, casein and soy protein had indistinguishable effects on lipoprotein levels. Our two studies together suggest that the level of cholesterol intake may determine whether plant and animal dietary proteins have similar or different effects on plasma LDL and HDL concentrations.     

Dietary cholesterol from eggs increases plasma HDL cholesterol in overweight men consuming a carbohydrate-restricted diet

Carbohydrate-restricted diets (CRD) significantly decrease body weight and independently improve plasma triglycerides (TG) and HDL cholesterol (HDL-C). Increasing intake of dietary cholesterol from eggs in the context of a low-fat diet maintains the LDL cholesterol (LDL-C)/HDL-C for both hyper- and hypo-responders to dietary cholesterol. In this study, 28 overweight/obese male subjects (BMI = 25-37 kg/m2) aged 40-70 y were recruited to evaluate the contribution of dietary cholesterol from eggs in a CRD. Subjects were counseled to consume a CRD (10-15% energy from carbohydrate) and they were randomly allocated to the EGG group [intake of 3 eggs per day (640 mg/d additional dietary cholesterol)] or SUB group [equivalent amount of egg substitute (0 dietary cholesterol) per day]. Energy intake decreased in both groups from 10,243 +/- 4040 to 7968 +/- 2401 kJ (P < 0.05) compared with baseline. All subjects irrespective of their assigned group had reduced body weight and waist circumference (P < 0.0001). Similarly, the plasma TG concentration was reduced from 1.34 +/- 0.66 to 0.83 +/- 0.30 mmol/L after 12 wk (P < 0.001) in all subjects. The plasma LDL-C concentration, as well as the LDL-C:HDL-C ratio, did not change during the intervention. In contrast, plasma HDL-C concentration increased in the EGG group from 1.23 +/- 0.39 to 1.47 +/- 0.38 mmol/L (P < 0.01), whereas HDL-C did not change in the SUB group. Plasma glucose concentrations in fasting subjects did not change. Eighteen subjects were classified as having the metabolic syndrome (MetS) at the beginning of the study, whereas 3 subjects had that classification at the end. These results suggest that including eggs in a CRD results in increased HDL-C while decreasing the risk factors associated with MetS.     

Effects of dietary fiber on the glucose tolerance in spontaneously diabetic rats--comparison among barley,rice, and corn starch

OBJECTIVES: In this study, the effects of a barley diet containing high dietary fiber on the onset and development of diabetes mellitus in spontaneously diabetic rats was investigated by comparing with a rice diet containing low dietary fiber and an alpha-corn starch diet containing very low dietary fiber. METHODS: 30 male Goto-Kakizaki (GK) strain rats (8 weeks of age) were randomly assigned to 3 groups; high barley (HB) group on a barley diet (dietary fiber intake, 1.79 g/day/rat), rice (R) group on a rice diet (dietary fiber intake, 0.46 g/day/rat), and alpha-corn starch (CS) group on an alpha-corn starch diet (dietary fiber intake, 0.24 g/day/rat). The carbohydrate (70%), fat (10%), and protein (20%) contents of these 3 diets were equal, and the rats were pair-fed each diet for 3 months. RESULTS: Feeding for 3 months showed that fasting plasma glucose level in the HB group was significantly lower than in the R and CS groups; the glucose tolerance in the HB group was markedly improved. Moreover, the plasma cholesterol and triglyceride levels in the HB group were significantly lower than those of the R and CS groups. CONCLUSIONS: Our findings demonstrated that barley enabled glycemic control and improved glucose tolerance compared with rice or alpha-corn starch.     

Diet and waist-to-hip ratio: important predictors of lipoprotein levels in sedentary and active young men with no evidence of cardiovascular disease

OBJECTIVE: Healthy, young men were studied to determine the relationship of energy and nutrient intake and physical activity to concentrations of plasma lipoprotein and cholesteryl ester transfer protein. DESIGN: A cross-sectional study compared active and sedentary male subjects (17 to 35 years old) with no personal or family history of coronary heart disease. Participants kept 20-day food and activity journals. Individual intakes of energy, protein, carbohydrate, fat, saturated fat, monounsaturated fatty acids, polyunsaturated fatty acids, dietary fiber, and alcohol were evaluated. Measurements of blood lipids (total cholesterol and triglycerides, high- and low-density lipoprotein cholesterol); apolipoproteins; cholesteryl ester transfer protein; anthropometric variables (body mass index, waist-to-hip ratio, percentage of body fat); and aerobic capacity were taken during fall and spring data collection periods. SUBJECT SELECTION: Subjects were selected on the basis of normal blood lipid levels, absence of underlying disease, and willingness to comply with their current level of physical activity for the duration of the study. Minimal sample size for statistical power was 12 men per group: 12 of 15 subjects who exercised and 13 of 15 subjects who were sedentary completed all phases of the study. STATISTICAL ANALYSES: Statistical analyses consisted of 2-way analysis of variance (activity level and season). Pearson product moment correlations and multiple regression analyses were conducted to assess whether energy and nutrient intakes, physical activity status, and/or anthropometric variables predicted plasma concentrations of lipids and apolipoproteins. RESULTS: Lower waist-to-hip ratio, and not specifically activity level, was associated with higher levels of high-density lipoprotein cholesterol (HDL-C) and lower levels of low-density lipoprotein cholesterol (LDL-C). Dietary intake of saturated and monounsaturated fats and alcohol predicted changes in some apolipoprotein and lipoprotein levels. APPLICATIONS: Use of waist-to-hip ratio in the primary prevention of coronary heart disease is a simple and cost-effective measure to predict development of abnormal lipoprotein profiles in young men. Specific dietary recommendations include adoption of a heart-healthy diet with emphasis on monounsaturated fatty acids (10% to 12% of energy or one third of total fat intake) and the suggestion that small amounts of alcohol (< 3 drinks per week) may, indeed, be beneficial. Because alcohol and waist-to-hip ratio were both important predictors of LDL-C level, even in active young men, the consumption of low levels of alcohol may be beneficial only if waist-to-hip ratio is maintained within the healthful range by achieving an appropriate balance of physical activity and macronutrient intake.     

Dietary chitosan improves hypercholesterolemia in rats fed high-fat diets

The hypolipidemic mechanism of chitosan was investigated in male Sprague-Dawley rats. Animals were divided into 5 groups (n = 8): a normal fat control group, a high-fat control group (HF), a positive control group (CR), and 2 chitosan groups (CIS1 and CIS2). Chitosan was fed at the beginning (CIS1) and after 2 weeks (CIS2). A commercial diet with 5% (wt/wt) cellulose (HF), cholestyramine (CR), or chitosan (CIS1, CIS2) was fed for 6 weeks. Chitosan did not affect food intake but decreased body weight gain and significantly increased fecal fat and cholesterol excretion, reduced the lipid level in plasma and liver, increased liver hepatic and lipoprotein lipase activities compared with HF (P < .05), and tended to relieve the degenerated fatty liver tissue. No significant differences in all measurements were found between the CIS1 and CIS2 groups although the CIS1 rats exhibited lower lipid levels compared to those in the CIS2 group. The results suggest that chitosan reduced the absorption of dietary fat and cholesterol in vivo and could effectively improve hypercholesterolemia in rats.     

Effects of reduced-fat diets consumed ad libitum on intake of nutrients, particularly antioxidant vitamins

OBJECTIVES: To determine whether a reduced-fat diet consumed ad libitum can achieve the recommended intakes of other macronutrients, fiber, and cholesterol and whether such a diet affects intake of other important micronutrients such as fat-soluble vitamins. DESIGN: Twelve-month, randomized, controlled trial of a reduced-fat, ad libitum diet vs usual diet. SUBJECTS: One hundred ten adults older than 40 years with glucose intolerance (2-hour blood glucose concentration = 7.0 to 11.0 mmol/L) who were selected from a previous workforce survey. INTERVENTION: Monthly small-group meetings aimed at identifying sources of dietary fat and ways to reduce fat consumption. MAIN OUTCOME MEASURES: Nutrient intakes derived from 3-day food diaries at the beginning and end of the study. Blood levels of retinol, alpha-tocopherol, and beta carotene at the end of the study. STATISTICAL ANALYSES PERFORMED: Unpaired t tests for determining changes in nutrient intake and antioxidant vitamin concentrations. Separate analyses were conducted with users of mineral and vitamin supplements and people who changed smoking status to reduce potential confounding. RESULTS: Fat intake decreased from 35% to 26% of energy in the reduced-fat diet group compared with a 2% decrease in the control group (P < .0001). Total energy intake also decreased in the 2 groups (-362 vs -59 kcal/day, P < .02). Those changes were reflected in a 3.1 +/- 4.7 kg (mean +/- standard deviation) weight loss in the intervention group compared with a 0.4 +/- 3.0 kg weight gain in the control group (P < .0001). There were no differences between groups in the changes in micronutrient intakes, except for an energy-adjusted increase in beta carotene intake in the reduced-fat diet group. Serum retinol and alpha-tocopherol concentrations were not different between the groups, but the reduced-fat diet group had higher beta carotene concentrations (P = .009). APPLICATIONS: A reduced-fat, ad libitum diet can be prescribed to improve overall macronutrient intake and achieve modest weight loss without sacrificing micronutrient intakes.     

Mechanisms of cholesterol-lowering effects of dietary insoluble fibres: relationships with intestinal and hepatic cholesterol parameters

Fibres with a range of abilities to perturb cholesterol homeostasis were used to investigate how the serum cholesterol-lowering effects of insoluble dietary fibres are related to parameters of intestinal cholesterol absorption and hepatic cholesterol homeostasis in mice. Cholestyramine, chitosan and cellulose were used as examples of fibres with high, intermediate and low bile acid-binding capacities, respectively. The serum cholesterol levels in a control group of mice fed a high fat/high cholesterol (HFHC) diet for 3 weeks increased about 2-fold to 4.3 mm and inclusion of any of these fibres at 7.5 % of the diet prevented this increase from occurring. In addition, the amount of cholesterol accumulated in hepatic stores due to the HFHC diet was reduced by treatment with these fibres. The three kinds of fibres showed similar hypocholesterolaemic activity; however, cholesterol depletion of liver tissue was greatest with cholestyramine. The mechanisms underlying the cholesterol-lowering effect of cholestyramine were (1) decreased cholesterol (food) intake, (2) decreased cholesterol absorption efficiency, and (3) increased faecal bile acid and cholesterol excretion. The latter effects can be attributed to the high bile acid-binding capacity of cholestyramine. In contrast, incorporation of chitosan or cellulose in the diet reduced cholesterol (food) intake, but did not affect either intestinal cholesterol absorption or faecal sterol output. The present study provides strong evidence that above all satiation and satiety effects underlie the cholesterol-lowering properties of insoluble dietary fibres with moderate or low bile acid-binding capabilities.     

Weight loss is correlated with an improved lipoprotein profile in obese postmenopausal women

BACKGROUND: Changes in plasma lipid and lipoprotein distributions that occur after menopause increase the risk of cardiovascular disease in women, especially in those who are overweight. OBJECTIVE: The purpose of this study was to evaluate the impact of a nine-month weight reduction program on plasma lipids, dietary intake and abdominal fat obesity. DESIGN: A partial crossover design was used to study a weight loss treatment consisting of Phentermine hydrochloride (Fastin, SmithKline Beecham Pharmaceuticals, Philadelphia, PA) therapy plus a low energy diet (5040 kJ/d). Forty-seven obese, postmenopausal Caucasian women (BMI of 30-38 kg/m2) were randomized into two groups, both of which received drug and diet treatment over six months. However, Group I started the intervention program three months later than Group II. Plasma total, HDL and LDL cholesterol and triacylglycerol were measured, body composition was assessed by anthropometry and dual energy x-ray absorptiometry, and food frequency records were collected at four timepoints. RESULTS: Over nine months, women in Group II reduced body weight (14.4%), lowered plasma concentrations of LDL cholesterol (14% to 26%) and triacylglycerol (15%) and raised plasma HDL cholesterol concentration (15%). These plasma lipid changes decreased the total cholesterol/HDL cholesterol ratio from 4.3 to 3.2. All subjects decreased abdominal fat measurements and energy and cholesterol intakes, as well as percentage of energy derived from total and saturated fat during the study. Most subjects also increased dietary fiber consumption. CONCLUSION: Both weight loss and diet modifications are associated with an improved plasma lipid profile in obese postmenopausal women.     

Effect of palm oil on plasma lipoprotein concentrations and plasma low-density lipoprotein composition in non-human primates

Palm oil (PO) contains ~43% of palmitic acid. It is the most abundant saturated fatty acid in the diet and it is generally considered the primary cholesterol (C)-raising fatty acid. However, the effect of palmitic acid on plasma cholesterol appears to depend on the cholesterol content of the diet. The aim of this study was to determine the effect of PO with either a high-fat, high-C or moderate-fat, moderate-C diet on lipoprotein C and low-density lipoprotein (LDL) composition. Fifty adult, male vervet monkeys were randomly assigned to the high-fat diet group (HFD: 35%E fat, ~0.106 mg C/kJ; n =20) and the moderate-fat diet group (MFD: 30%E fat, ~0.027 mg C/kJ; n =30). Baseline LDL-C, high-density lipoprotein (HDL)-C and body weight were used to stratify the vervets into comparable experimental groups within each dietary group. The HFD group was divided into two groups of 10 each: one group continued with the HFD in which 8.1%E was derived from lard (AF); in the other group, AF was substituted isocalorically with PO. The MFD group was divided into three groups of 10 each: one group continued with the MFD in which 11.8%E was derived from AF; in the other two groups, the AF was substituted isocalorically with either sunflower oil (SO) or PO. This article presents preliminary results on plasma lipoproteins and LDL composition after 6 months of dietary intervention. Plasma total and LDL-C was higher in all the groups, but the mean changes elicited by PO with either the HFD or MFD were no different from that observed with AF and SO. There was no difference in the mean change of LDL molecular weight within the HFD and MFD. It is concluded that PO is no different from AF (HFD and MFD) or SO (MFD) in its cholesterolaemic effect.     

Influence of dietary carbohydrates on cholesterol metabolism in casein-fed rabbits

Dietary carbohydrates consisting of cornstarch and dextrose, as well as molassesenriched dextrose, were fed to rabbits in a high fat, cholesterol-free casein purified diet in order to evaluate their influence on food intake, and more specifically on the magnitude of the cholesterol response to casein feeding. Food intake and weight gain were similar in all groups, regardless of carbohydrate origin. The non-significant trend in serum cholesterol elevation in the molasses+dextrose group was however translated by a significant increase in its LDL-cholesterol, compared to the cornstarch and dextrose groups. Moreover, the significant increase in HDL-C and 4,3-fold decrease in the LDL-C/HDL-C ratio induced by cornstarch, in comparison to the dextrose and dextrose+molasses groups, suggests that the atherosclerosis risk associated to casein intake may be attenuated by the use of cornstarch. In addition, significantly higher liver cholesterol and TG levels following molasses+dextrose feeding, compared to dextrose and cornstarch, suggests that molasses enhances the effects of casein on serum cholesterol by a series of reactions originating from an increase in this group's hepatic lipids.     

Dietary intake and changes in lipoprotein lipids in obese, postmenopausal women placed on an American Heart Association Step 1 diet

BACKGROUND: Dietary intake and changes in lipoprotein lipids in obese, postmenopausal women placed on an American Heart Association Step 1 diet. OBJECTIVE: The purpose of this study was to determine the specific dietary factors associated with the commonly observed decrease in HDL-C concentration in obese, postmenopausal women placed on a low-fat diet. DESIGN/SUBJECTS/INTERVENTION: Dietary intake, lipoprotein lipid concentrations, and body weight were measured before and after 10 weeks of instruction in the principles of the American Heart Association (AHA) Step 1 diet in 55 overweight and obese (body mass index=33+/-4 kg/m2), sedentary, postmenopausal women (mean age 59+/-5 years). RESULTS: The percent of energy obtained from total fat, monounsaturated, polyunsaturated, saturated fat, and dietary cholesterol decreased significantly after dietary intervention, while the polyunsaturated:saturated ratio and the percent of energy obtained from total carbohydrate, complex carbohydrate, and simple carbohydrate increased. On average, the women lost a small, but significant, amount of body weight (2%+/-3%, P<.0001). Adherence to the AHA diet reduced total cholesterol (-8%+/-8%), LDL-C (-6%+/-11%), and HDL-C (-16%+/-10%). The only dietary change that predicted decreases in HDL-C concentrations was the increase in the percent of energy from simple sugar (r=-0.32, P<.05). There were no relationships between changes in HDL-C and changes in percent of energy from fat (r=0.16), saturated fat (r=0.07), polyunsaturated fat (r=0.04), or monounsaturated fat (r=0.09). APPLICATIONS/CONCLUSIONS: In postmenopausal women, a dietary reduction in total fat, saturated fat, and cholesterol reduces body weight, total cholesterol, and LDL-C, but substitution of simple sugar for dietary fat may lead to a reduction in HDL-C. Further research is needed to determine which specific simple sugars are contributing to diet-induced reductions in HDL-C in older women placed on a low-fat diet.