Continuous intake of polyphenolic compounds containing cocoa powder reduces LDL oxidative susceptibility and has beneficial effects on plasma HDL-cholesterol concentrations in humans

BACKGROUND: Cocoa powder is rich in polyphenols such as catechins and procyanidins and has been shown in various models to inhibit LDL oxidation and atherogenesis. OBJECTIVE: We examined whether long-term intake of cocoa powder alters plasma lipid profiles in normocholesterolemic and mildly hypercholesterolemic human subjects. DESIGN: Twenty-five subjects were randomly assigned to ingest either 12 g sugar/d (control group) or 26 g cocoa powder and 12 g sugar/d (cocoa group) for 12 wk. Blood samples were collected before the study and 12 wk after intake of the test drinks. Plasma lipids, LDL oxidative susceptibility, and urinary oxidative stress markers were measured. RESULTS: At 12 wk, we measured a 9% prolongation from baseline levels in the lag time of LDL oxidation in the cocoa group. This prolongation in the cocoa group was significantly greater than the reduction measured in the control group (-13%). A significantly greater increase in plasma HDL cholesterol (24%) was observed in the cocoa group than in the control group (5%). A negative correlation was observed between plasma concentrations of HDL cholesterol and oxidized LDL. At 12 wk, there was a 24% reduction in dityrosine from baseline concentrations in the cocoa group. This reduction in the cocoa group was significantly greater than the reduction in the control group (-1%). CONCLUSION: It is possible that increases in HDL-cholesterol concentrations may contribute to the suppression of LDL oxidation and that polyphenolic substances derived from cocoa powder may contribute to an elevation in HDL cholesterol.     

Macadamia nut consumption lowers plasma total and LDL cholesterol levels in hypercholesterolemic men

This study was conducted to assess the cholesterol-lowering potential of macadamia nuts. Seventeen hypercholesterolemic men (mean age 54 y) were given macadamia nuts (40-90 g/d), equivalent to 15% energy intake, for 4 wk. Plasma total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides and homocysteine concentrations and the fatty acid composition of plasma lipids were determined before and after treatment. Plasma MUFA 16:1(n-7), 18:1(n-7) and 20:1(n-9) were elevated after intervention with macadamia nuts. Plasma (n-6) and (n-3) PUFA concentrations were unaffected by macadamia nut consumption. Plasma total cholesterol and LDL cholesterol concentrations decreased by 3.0 and 5.3%, respectively, and HDL cholesterol levels increased by 7.9% in hypercholesterolemic men after macadamia nut consumption. Plasma triglyceride and homocysteine concentrations were not affected by treatment. Macadamia nut consumption was associated with a significant increase in the relative intake of MUFA and a reduced relative intake of saturated fatty acids and PUFA. This study demonstrates that macadamia nut consumption as part of a healthy diet favorably modifies the plasma lipid profile in hypercholesterolemic men despite their diet being high in fat.     

Effects of cocoa powder and dark chocolate on LDL oxidative susceptibility and prostaglandin concentrations in humans.

BACKGROUND: Flavonoids are polyphenolic compounds of plant origin with antioxidant effects. Flavonoids inhibit LDL oxidation and reduce thrombotic tendency in vitro. Little is known about how cocoa powder and dark chocolate, rich sources of polyphenols, affect these cardiovascular disease risk factors. OBJECTIVE: We evaluated the effects of a diet high in cocoa powder and dark chocolate (CP-DC diet) on LDL oxidative susceptibility, serum total antioxidant capacity, and urinary prostaglandin concentrations. DESIGN: We conducted a randomized, 2-period, crossover study in 23 healthy subjects fed 2 diets: an average American diet (AAD) controlled for fiber, caffeine, and theobromine and an AAD supplemented with 22 g cocoa powder and 16 g dark chocolate (CP-DC diet), providing approximately 466 mg procyanidins/d. RESULTS: LDL oxidation lag time was approximately 8% greater (P = 0.01) after the CP-DC diet than after the AAD. Serum total antioxidant capacity measured by oxygen radical absorbance capacity was approximately 4% greater (P = 0.04) after the CP-DC diet than after the AAD and was positively correlated with LDL oxidation lag time (r = 0.32, P = 0.03). HDL cholesterol was 4% greater after the CP-DC diet (P = 0.02) than after the AAD; however, LDL-HDL ratios were not significantly different. Twenty-four-hour urinary excretion of thromboxane B(2) and 6-keto-prostaglandin F(1)(alpha) and the ratio of the 2 compounds were not significantly different between the 2 diets. CONCLUSION: Cocoa powder and dark chocolate may favorably affect cardiovascular disease risk status by modestly reducing LDL oxidation susceptibility, increasing serum total antioxidant capacity and HDL-cholesterol concentrations, and not adversely affecting prostaglandins.     

Flaxseed oil supplementation does not affect plasma lipoprotein concentration or particle size in human subjects

alpha-Linolenic acid (ALA) is a major dietary (n-3) fatty acid. Some clinical trials with ALA supplementation have shown reduced cardiovascular risk; however the specific cardioprotective mechanism is not known. We studied the effects of daily supplementation with ALA derived from flaxseed oil on concentrations of plasma LDL cholesterol, HDL cholesterol, intermediate density lipoprotein cholesterol, and lipid particle sizes. In a randomized double-blind trial, 56 participants were given 3 g/d of ALA from flaxseed oil in capsules (n = 31) or olive oil containing placebo capsules (n = 25) for 26 wk. Changes in plasma HDL cholesterol, LDL cholesterol, and triglyceride concentrations did not differ between the 2 groups at 26 wk. The adjusted plasma total cholesterol concentration at 26 wk was 0.45 mmol/L higher in the flaxseed oil group (5.43 +/- 0.03 mmol/L) compared with the olive oil group (5.17 +/- 0.07 mmol/L) (P = 0.026). ALA did not affect LDL, HDL, or IDL particle size; however, the concentrations of the large, less atherogenic LDL1 (P = 0.058) and LDL2 (P = 0.083) subfractions tended to be greater in the ALA group. In conclusion, ALA does not decrease CVD risk by altering lipoprotein particle size or plasma lipoprotein concentrations.     

Tomato juice decreases LDL cholesterol levels and increases LDL resistance to oxidation

High dietary intakes of tomato products are often associated with a reduced risk of CVD, but the atheroprotective mechanisms have not been established. This study was conducted to investigate the effects of increased dietary intake of tomato products on plasma lipids and LDL oxidation. The diet intervention included a baseline period, a 3-week low tomato diet (no tomato products allowed) and a 3-week high tomato diet (400 ml tomato juice and 30 mg tomato ketchup daily). Twenty-one healthy study subjects participated in the study. Total cholesterol concentration was reduced by 5.9 (sd 10) % (P = 0.002) and LDL cholesterol concentration by 12.9 (sd 17.0) % (P = 0.0002) with the high tomato diet compared to the low tomato diet. The changes in total and LDL cholesterol concentrations correlated significantly with the changes in serum lycopene (r 0.56, P = 0.009; r 0.60, P = 0.004, total and LDL, respectively), beta-carotene (r 0.58, P = 0.005; r 0.70, P < 0.001) and gamma-carotene concentrations (r 0.64, P = 0.002; r 0.64, P = 0.002). The level of circulating LDL to resist formation of oxidized phospholipids increased 13 % (P = 0.02) in response to the high tomato diet. In conclusion, a high dietary intake of tomato products had atheroprotective effects, it significantly reduced LDL cholesterol levels, and increased LDL resistance to oxidation in healthy normocholesterolaemic adults. These atheroprotective features associated with changes in serum lycopene, beta-carotene and gamma-carotene levels.     

Serum lipid and apolipoprotein concentrations in healthy men on diets enriched in either canola oil or safflower oil

This randomized, blind study measured changes in serum lipid and apolipoprotein concentrations in 16 men consuming 39 +/- 1% of energy (en%) as fat either from safflower- or canola-oil-based diets for 8 wk. Initially, the men were stabilized for 3 wk on a typical American (baseline) diet. Compared with baseline, the vegetable-oil-based diets reduced serum total cholesterol 9-15% (P less than 0.002), low-density-lipoprotein (LDL)-cholesterol 12-20% (P less than 0.002), and apolipoprotein B-100 21-24% (P less than 0.001). There were no significant changes from baseline to the end of the study in serum triglycerides, total high-density-lipoprotein (HDL) cholesterol, HDL3 cholesterol, HDL2 cholesterol, or apolipoprotein A-I. These data suggest that even if total fat intake remains at 39-40 en%, many men show lowered LDL cholesterol if saturated fatty acid intake is minimized and that diets high in polyunsaturated fatty acids do not necessarily lower HDL-cholesterol concentrations.     

A combination therapy including psyllium and plant sterols lowers LDL cholesterol by modifying lipoprotein metabolism in hypercholesterolemic individuals

We conducted a randomized, double blind, crossover, placebo-controlled study to determine the effects of a combination therapy including plant sterols (PS) and psyllium (PSY), provided via cookies, on plasma lipids and on the size and subfraction distribution of VLDL, LDL, and HDL. Thirty-three healthy free-living individuals (11 males and 22 females), aged 35-65 y, with a BMI between 25 and 35 kg/m(2) and initial plasma LDL cholesterol (LDL-C) concentrations between 2.6 and 4.1 mmol/L (100 and 160 mg/dL), were randomly assigned to receive treatment cookies (7.68 g/d PSY and 2.6 g/d PS) or placebo cookies (0 g PSY+PS) for 4 wk. After a 3-wk washout period, subjects received the other cookies for an additional 4 wk. Plasma total cholesterol concentrations were significantly reduced for all subjects, from 5.65 +/- 0.72 mmol/L after the placebo period to 5.28 +/- 0.76 mmol/L after the PSY+PS cookie period (P < 0.01). These reductions were primarily in LDL-C, which decreased from 3.48 +/- 0.70 to 3.14 +/- 0.78 mmol/L after PSY+PS cookie consumption (P < 0.01). Intake of the PSY+PS cookie decreased the number of intermediate density lipoprotein (IDL), LDL, and HDL particles (P < 0.05) and plasma apo B concentrations (P < 0.01). The decreases in LDL and HDL particles were in the small subfractions. Because smaller LDL particles are associated with an increased risk of heart disease and because smaller HDL particles are indicative of diminished reverse cholesterol transport, we conclude that the combination therapy resulted in a less atherogenic lipoprotein profile. In addition, the evaluation of lipoprotein subfractions resulting from the action of the fiber and plant sterols in the intestinal lumen provides an insight on the secondary mechanisms of plasma LDL-C lowering.     

Oxidized fatty acids promote atherosclerosis only in the presence of dietary cholesterol in low-density lipoprotein receptor knockout mice

Studies suggest that heated oils contribute to the presence of oxidized components in the circulating lipoproteins and to the development of atherosclerosis in animals. We evaluated the effects of 11-13 wk of consumption of a well defined dietary oxidized fatty acid, 13-hydroxylinoleic acid (13-HODE) (8 mg), on atherosclerotic lesion development and plasma cholesterol concentrations in mice fed diets varying in fat and cholesterol contents. LDL receptor knockout mice were used in two feeding studies. In study 1, oxidized fatty acid consumption in association with a high fat diet increased aortic lesion areas by >100% (P < 0.05). Surprisingly, oxidized fatty acid intake also tended to increase plasma total cholesterol (P = 0.12) and LDL cholesterol (P < 0.05) as well as oxidative stress as measured by higher levels of autoantibodies to oxidatively modified proteins (P = 0.008). However, in mice fed a nonpurified diet, oxidized fatty acids were not atherogenic and may even have been beneficial, as indicated by a lower plasma triglyceride (TG) concentration (P < 0.05). In study 2, mice were fed either a high fat, medium fat or low fat diet to evaluate whether the increase in aortic lesions due to oxidized fatty acid consumption in study 1 was a result of the associated higher plasma total and LDL cholesterol concentrations. In study 2, 13-HODE-treated mice in the medium and low fat diet groups but not those fed the high fat diet had larger atherosclerotic lesions (P < 0.05). Additionally, plasma total and LDL cholesterol as well as TG were not affected by HODE treatment. However, the total cholesterol:HDL cholesterol ratio was higher in treated mice (P < 0.05) and HDL cholesterol was lower in HODE-treated mice that were fed the low fat diet (P < 0.05). Our results suggest that, in mice fed cholesterol, oxidized fatty acids may be atherogenic, both in terms of increased oxidative stress (as seen in study 1) and by increasing the atherogenicity of the plasma cholesterol profile.     

Relation between soy-associated isoflavones and LDL and HDL cholesterol concentrations in humans: a meta-analysis

BACKGROUND: Differences in isoflavone content of soy protein may explain the absence of a dose-response relation between soy protein intake and blood cholesterol concentrations. OBJECTIVE: To study specifically the effect of soy-associated isoflavones on cholesterol concentrations in well-controlled trials substituting soy protein with dairy or animal protein. DESIGN: Studies were identified by MEDLINE searches (1995 - 6 June 2002) and reviewing reference lists. Studies were included if they had a control group or treatment, experimental diets only differed in the amounts of soy protein and isoflavones and were each fed for at least 14 days. A total of 10 studies met these criteria, providing 21 dietary comparisons. SUBJECTS:: Studies comprised 959 subjects (336 men and 623 women), average age ranged from 41 to 67 y and baseline cholesterol concentration from 5.42 to 6.60 mmol/l. INTERVENTIONS: The intake of soy-associated isoflavones increased by 1-95 mg/day and the intake of soy protein increased by 19-60 g/day. RESULTS: Feeding daily 36 g soy protein with 52 mg soy-associated isoflavones on average decreased low-density lipoprotein (LDL) cholesterol by -0.17+/-0.04 mmol/l (mean+/-s.e.) and increased high-density lipoprotein (HDL) cholesterol by 0.03+/-0.01 mmol/l. There was no dose-response relation between soy-associated isoflavones and changes in LDL cholesterol (R=-0.33, P=0.14) (Pearson correlation coefficient) or HDL cholesterol (R=-0.07, P=0.76) or their ratio. CONCLUSIONS: Consumption of soy-associated isoflavones is not related to changes in LDL or HDL cholesterol.     

Fish consumption shifts lipoprotein subfractions to a less atherogenic pattern in humans

The effect of fish consumption on plasma lipoprotein subfraction concentrations was studied in 22 men and women (age > 40 y). Subjects were provided an average American diet (AAD, 35% of energy as fat, 14% as saturated fat, and 35 mg cholesterol/MJ) for 6 wk before being assigned to a National Cholesterol Education Program (NCEP) Step 2 high-fish diet (n = 11, 26% of energy as fat, 4.5% as saturated fat, and 15 mg cholesterol/MJ) or a NCEP Step 2 low-fish diet (n = 11, 26% of energy as fat, 4.0% as saturated fat, and 11 mg cholesterol/MJ) for 24 wk. All food and drink were provided to study participants. Consumption of the high-fish NCEP Step 2 diet was associated with a significant reduction in medium and small VLDL, compared with the AAD diet, whereas the low-fish diet did not affect VLDL subfractions. Both diets significantly reduced LDL cholesterol concentrations, without modifying LDL subfractions. Both diets also lowered HDL cholesterol concentrations. However, the high-fish diet significantly lowered only the HDL fraction containing both apolipoprotein (apo) AI and AII (LpAI:AII) and did not change HDL subfractions assessed by NMR, whereas the low-fish diet significantly lowered the HDL fraction containing only apo AI (LpAI) and the large NMR HDL fractions, resulting in a significant reduction in HDL particle size. Neither diet affected VLDL and LDL particle size. Our data indicate that within the context of a diet restricted in fat and cholesterol, a higher fish content favorably affects VLDL and HDL subspecies.     

Lime-treated maize husks lower plasma LDL-cholesterol levels in normal and hypercholesterolaemic adult men from northern Mexico

Lime-treated maize husks (LTCH), a by-product of tortilla manufacturing in Mexico, have been shown to decrease plasma LDL-cholesterol levels in guinea-pigs by specific alterations in hepatic cholesterol metabolism. To determine whether LTCH would also lower plasma cholesterol levels in normal and hyperlipidaemic individuals, the fibre content of a typical diet was increased by supplementing free-living subjects in North-West Mexico with cookies containing 450 g LTCH/kg. Normal subjects (n 11) with plasma cholesterol levels of less than 5.7 mmol/l and hypercholesterolaemic subjects (n 12) with plasma cholesterol levels higher than 5.7 mmol/l participated in the study. Plasma glucose, cholesterol, triacylglycerol, LDL-cholesterol and HDL-cholesterol concentrations, LDL:HDL values and blood pressure were determined at baseline and after 6 weeks of supplementation with LTCH. LTCH supplementation significantly lowered the plasma total cholesterol level by 11-15% and LDL-cholesterol by 25%, and improved the LDL:HDL value by 29-33% (P < 0.01) in both normal and hypercholesterolaemic subjects. HDL-cholesterol, triacylglycerol and glucose concentrations did not change. Both groups consumed equal amounts of LTCH per week; individuals showed excellent compliance and good acceptance of the product. Neither group changed their dietary habits during the time of the experiment as determined by 3 d dietary records at baseline and at week 6. We conclude that LTCH supplements are suitable to increase fibre intake and reduce plasma LDL-cholesterol levels in healthy and hypercholesterolaemic subjects in this population.     

Hepatic LDL receptor mRNA in rats is increased by dietary mushroom (Agaricus bisporus) fiber and sugar beet fiber

Plasma cholesterol concentration is reduced by feeding some dietary fibers and mushroom fruit body, but the mechanism is not fully understood. We examined the effects of mushroom (Agaricus bisporus) fiber and sugar beet fiber on serum cholesterol and hepatic LDL receptor mRNA in rats. Rats were fed a cholesterol-free diet with 50 g/kg cellulose powder (CP), 50 g/kg mushroom (Agaricus bisporus) fiber (MSF) or 50 g/kg sugar beet fiber (BF) for 4 wk. There were no significant differences in the body weight, food intake and cecum weight among the groups. The relative liver weight in the CP group was significantly greater than that in the MSF and BF groups. The cecal pH in the CP and MSF groups was significantly higher than that in the BF group. Cecal acetic acid, butyric acid and total short-chain fatty acid (SCFA) concentrations in the BF group were significantly higher than those in the other groups. The serum total cholesterol, VLDL + intermediate density lipoprotein (IDL) + LDL cholesterol concentrations in the CP group were significantly greater than those in the MSF and BF groups. The HDL cholesterol concentration in the MSF group was significantly lower than that in the CP group. The hepatic LDL receptor mRNA level in the MSF and BF groups was significantly higher than that in the CP group. The results of this study demonstrate that mushroom fiber and sugar beet fiber lowered the serum total cholesterol level by enhancement of the hepatic LDL receptor mRNA.     

Linoleic acid lowers LDL cholesterol without a proportionate displacement of saturated fatty acid

We tested the specificity of the plasma cholesterol-lowering effect of linoleic acid in a comparison of linoleate-rich and saturated fatty acid-rich foods. Twelve mildly hypercholesterolemic men and women ate the two diets for three weeks each in a random cross-over design, after a two-week baseline period. A linoleic acid-rich supplement was added to the baseline diet so that the saturated and monounsaturated fatty acid content did not change significantly. Despite the consequent increase in total fat intake, the linoleate-rich diet (23 per cent energy from polyunsaturated fatty acids) significantly lowered plasma total and low-density lipoprotein (LDL) cholesterol (-8 per cent and -14 per cent respectively), while high-density lipoprotein (HDL) cholesterol rose 8 per cent. The direction of these changes was similar in all 12 subjects. Compared with a supplement that raised dietary saturated fatty acids to 30 per cent energy, the linoleate acid-rich diet gave lower total cholesterol (-14 per cent), LDL cholesterol (-18 per cent) and HDL cholesterol (-12 per cent) concentrations. Linoleic acid lowers LDL cholesterol even when saturated fatty acids are not significantly displaced and substantially more when there is such displacement.     

Carbohydrate restriction alters lipoprotein metabolism by modifying VLDL, LDL, and HDL subfraction distribution and size in overweight men

To determine the effects of carbohydrate restriction (CR) with and without soluble fiber on lipoprotein metabolism, 29 men participated in a 12-wk weight loss intervention. Subjects were matched by age and BMI and randomly assigned to consume 3 g/d of either a soluble fiber supplement (n=14) or placebo (n=15) with a macronutrient energy distribution of approximately 10% carbohydrate, approximately 65% fat, and approximately 25% protein. Because the groups did not differ in any of the variables measured, all data were pooled and comparisons were made between baseline and 12 wk. After 12 wk, subjects had a mean weight loss of 7.5 kg (P<0.001), and abdominal fat was reduced by 20% (P<0.001). Plasma LDL cholesterol and triglycerides (TG) were significantly reduced by 8.9 and 38.6%, respectively. Similarly, apolipoproteins C-I (-13.8%), C-III (-21.2%) and E (-12.5%) were significantly lower after the intervention. In contrast plasma HDL-cholesterol concentrations were increased by 12% (P<0.05). Changes in plasma TG were positively correlated with reductions in large (r=0.615, P<0.01) and medium VLDL particles (r=0.432, P<0.05) and negatively correlated with LDL diameter (r=-0.489, P<0.01). Changes in trunk fat were positively correlated with medium VLDL (r=0.474, P<0.0) and small LDL (r=0.405, P<0.05) and negatively correlated with large HDL (r=-0.556, P<0.01). We conclude that weight loss induced by CR favorably alters the secretion and processing of plasma lipoproteins, rendering VLDL, LDL, and HDL particles associated with decreased risk for atherosclerosis and coronary heart disease.     

Fiber intakes and anthropometric measures are predictors of circulating hormone, triglyceride, and cholesterol concentrations in the women's health trial

The unhealthy eating patterns and obesity among women in the U.S. are indicated by changes in biomarkers, such as insulin, lipoproteins, and estradiol, that are risk factors for breast cancer and cardiovascular diseases. This article models the inter-relations among diet, serum insulin, estradiol, and sex hormone binding globulin (SHBG) concentrations, plasma LDL and HDL cholesterol, and net triglyceride concentrations, using the data at baseline and 12 mo on 379 and 615 postmenopausal women in the Control and Intervention groups, respectively, of the Women's Health Trial: Feasibility Study in Minority Populations. Subjects in the Intervention group received detailed advice over a period of 1 y for reducing fat intakes and increasing the consumption of whole grains and fruits and vegetables. The main findings were that there were significant differences between the Control and Intervention groups in the changes from baseline to 12 mo in LDL and HDL cholesterol and SHBG concentrations. Second, using a comprehensive random effects modeling framework, the ratio of fiber to energy intake was significantly associated (P < 0.05) with lower insulin and triglyceride levels, and with a higher HDL cholesterol concentration in the Intervention group. Third, the subjects' waist-to-hip ratio and BMI were significantly associated with insulin, SHBG, LDL and HDL cholesterol, and triglyceride concentrations. Fourth, insulin levels were significantly negatively associated with SHBG and HDL cholesterol, and positively associated with LDL cholesterol, triglyceride, and estradiol concentrations. Overall, weight loss, especially around the waist, and increased fiber intakes are likely to be beneficial for lipid, cholesterol, and hormone profiles of U.S. women.     

Effect of dietary fat and cholesterol on plasma lipids and lipoprotein fractions in normolipidemic men

In a controlled feeding situation, male subjects were assigned to one of four treatment groups: low fat (31% of total kcal)/low cholesterol (193 mg/d) (LFLC), low fat/usual cholesterol (504 mg/d) (LFUC), usual fat (46% of total kcal)/low cholesterol (UFLC) and usual fat/usual cholesterol (UFUC) intake. For the first 2 wk of the 10-wk study all subjects consumed the UFUC diet. Subjects consumed experimental diets during wk 3-7 and resumed their customary intake during wk 8-10. Plasma total, high-density-lipoprotein (HDL), low-density-lipoprotein and very-low-density-lipoprotein cholesterol and triglycerides were determined weekly. A significant effect (P less than 0.05) of dietary fat on plasma total and HDL cholesterol was observed between the end of wk 2 and 7. Low fat intake resulted in 17 +/- 2 mg/dL lower total cholesterol and 10 +/- 1 mg/dL lower HDL cholesterol than the usual fat intake. Plasma lipids were not affected either by dietary cholesterol or by any interaction of dietary fat with cholesterol.     

Cholesterol-lowering effects of psyllium-enriched cereal as an adjunct to a prudent diet in the treatment of mild to moderate hypercholesterolemia.

Psyllium hydrophilic mucilloid, rich in soluble fiber, significantly lowers serum cholesterol concentrations. To investigate the lipid-lowering effects of a ready-to-eat cereal enriched with psyllium, we studied 44 hypercholesterolemic ambulatory individuals for 7 wk, using a randomized, double-blind, parallel design. After a 1-wk baseline period, subjects were randomly assigned to consume 114 g/d of a psyllium-flake or wheat-bran-flake cerearl for 6 wk adjunctive to an American Heart Association Step I diet. Serum high-density-lipoprotein cholesterol and triglycerides remained unchanged throughout the study; however, serum cholesterol and low-density lipoprotein (LDL) concentrations were significantly lower on psyllium than on wheat-bran cereal. Additionally, serum total and LDL cholesterol values were significantly lower than baseline values in the psyllium group. The dietary nutrient intake of the two groups did not differ except for soluble fiber. Adding psyllium-enriched cereal to a prudent low-fat diet may enhance dietary management of hypercholesterolemia.     

Soy protein intake by perimenopausal women does not affect circulating lipids and lipoproteins or coagulation and fibrinolytic factors

Soy protein favorably alters serum lipids and lipoproteins in hypercholesterolemic individuals, thereby reducing cardiovascular disease risk. The primary purpose was to determine the effect of soy protein (40 g/d) on circulating lipids and lipoproteins or coagulation and fibrinolytic factors in normocholesterolemic and mildly hypercholesterolemic perimenopausal women. We also determined the contribution of coagulation and fibrinolytic and other factors (e.g., body size and composition; serum estrogens, ferritin, iron; dietary intake) to lipid profiles. Subjects were randomly assigned to treatment: isoflavone-rich soy (n = 24), isoflavone-poor soy (n = 24), or whey control (n = 21) protein. We measured circulating lipids and lipoproteins at baseline, wk 12 and wk 24, and coagulation/fibrinolytic factors at baseline and wk 24. Coagulation and fibrinolytic factors were not adversely affected by treatment. Treatment did not alter lipid profiles in mildly hypercholesterolemic (n = 30) or in all subjects combined. Time significantly (P < 0.001) affected serum total cholesterol, triacylglycerol, LDL cholesterol and HDL cholesterol concentrations. We could not attribute changes over time to various factors, but at baseline accounted for 57% of the variability in HDL cholesterol (P < or = 0.0001) and for 50% in the total to HDL cholesterol ratio (P < or = 0.0001). Dietary vitamin E and % energy from fat had positive effects, whereas plasma plasminogen activator inhibitor-1, fibrinogen, body weight and serum ferritin had negative effects on HDL and total to HDL cholesterol. Isoflavone-rich or isoflavone-poor soy protein had no effect on lipid profiles or coagulation and fibrinolytic factors, whereas the effect of time suggested that the hormonal milieu during the menopausal transition may have overridden any detectable treatment effect on lipids. The relationship between coagulation factors and serum lipids should be examined further as indices of cardiovascular disease risk in midlife women.     

Cholesterol-lowering effect of beta-glucan from oat bran in mildly hypercholesterolemic subjects may decrease when beta-glucan is incorporated into bread and cookies

BACKGROUND: Findings about the effects of beta-glucan on serum lipoproteins are conflicting. OBJECTIVE: The study investigated the effects of beta-glucan from oat bran in bread and cookies (study 1) and in orange juice (study 2) on serum lipoproteins in mildly hypercholesterolemic subjects. DESIGN: In study 1, 48 subjects (21 men, 27 women) received for 3 wk control bread and cookies rich in wheat fiber. For the next 4 wk, by random assignment, 23 subjects continued to consume the control products, and 25 received bread and cookies rich in beta-glucan. Mean daily intake of beta-glucan was 5.9 g. Total dietary fiber intake did not differ significantly between the groups. In study 2, the same sources of control fiber and beta-glucan (5 g/d) as in study 1 were provided. For 2 wk, 25 of the original 48 subjects (10 men, 15 women) were randomly assigned to consume orange juice containing either wheat fiber (n = 13) or beta-glucan from oat bran (n = 12). After a washout period of 1 wk, dietary regimens were crossed over. RESULTS: In study 1, the change in LDL cholesterol did not differ significantly (-0.12 mmol/L; P = 0.173) between the 2 groups. In study 2, the drink rich in beta-glucan decreased LDL cholesterol by 0.26 +/- 0.07 mmol/L (6.7 +/- 1.8%; P = 0.001) and the ratio of total to HDL cholesterol by 0.26 +/- 0.11 (5.4 +/- 2.1%; P = 0.029) compared with the other drink. HDL-cholesterol and triacylglycerol concentrations did not change significantly. CONCLUSIONS: The food matrix or the food processing, or both, could have adverse effects on the hypocholesterolemic properties of oat beta-glucan.     

Effect of low-fat, fermented milk enriched with plant sterols on serum lipid profile and oxidative stress in moderate hypercholesterolemia

BACKGROUND: Plant sterol (PS)-enriched foods have been shown to reduce plasma LDL-cholesterol concentrations. In most studies, however, PSs were incorporated into food products of high fat content. OBJECTIVE: We examined the effect of daily consumption of PS-supplemented low-fat fermented milk (FM) on the plasma lipid profile and on systemic oxidative stress in hypercholesterolemic subjects. DESIGN: Hypercholesterolemic subjects (LDL-cholesterol concentrations >or=130 and 相似文献