Soy isoflavones lower serum total and LDL cholesterol in humans: a meta-analysis of 11 randomized controlled trials

BACKGROUND: Clinical trials have reported the cholesterol-lowering effects of soy protein intake, but the components responsible are not known. OBJECTIVE: This meta-analysis was primarily conducted to evaluate the precise effects of soy isoflavones on lipid profiles. The effects of soy protein that contains enriched and depleted isoflavones were also examined. DESIGN: PUBMED was searched for English-language reports of randomized controlled trials published from 1990 to 2006 that described the effects of soy protein intake in humans. Eleven studies were selected for the meta-analysis. RESULTS: Soy isoflavones significantly decreased serum total cholesterol by 0.10 mmol/L (3.9 mg/dL or 1.77%; P = 0.02) and LDL cholesterol by 0.13 mmol/L (5.0 mg/dL or 3.58%; P < 0.0001); no significant changes in HDL cholesterol and triacylglycerol were found. Isoflavone-depleted soy protein significantly decreased LDL cholesterol by 0.10 mmol/L (3.9 mg/dL or 2.77%; P = 0.03). Soy protein that contained enriched isoflavones significantly decreased LDL cholesterol by 0.18 mmol/L (7.0 mg/dL or 4.98%; P < 0.0001) and significantly increased HDL cholesterol by 0.04 mmol/L (1.6 mg/dL or 3.00%; P = 0.05). The reductions in LDL cholesterol were larger in the hypercholesterolemic subcategory than in the normocholesterolemic subcategory, but no significant linear correlations were observed between reductions and the starting values. No significant linear correlations were found between reductions in LDL cholesterol and soy protein ingestion or isoflavone intakes. CONCLUSIONS: Soy isoflavones significantly reduced serum total and LDL cholesterol but did not change HDL cholesterol and triacylglycerol. Soy protein that contained enriched or depleted isoflavones also significantly improved lipid profiles. Reductions in LDL cholesterol were larger in hypercholesterolemic than in normocholesterolemic subjects.     

Plasma LDL and HDL cholesterol and oxidized LDL concentrations are altered in normo- and hypercholesterolemic humans after intake of different levels of cocoa powder

Cocoa powder is rich in polyphenols, such as catechins and procyanidins, and has been shown in a variety of subject models to inhibit oxidized LDL and atherogenesis. Our study evaluated plasma LDL cholesterol and oxidized LDL concentrations following the intake of different levels of cocoa powder (13, 19.5, and 26 g/d) in normocholesterolemic and mildly hypercholesterolemic humans. In this comparative, double-blind study, we examined 160 subjects who ingested either cocoa powder containing low-polyphenolic compounds (placebo-cocoa group) or 3 levels of cocoa powder containing high-polyphenolic compounds (13, 19.5, and 26 g/d for low-, middle-, and high-cocoa groups, respectively) for 4 wk. The test powders were consumed as a beverage after the addition of hot water, twice each day. Blood samples were collected at baseline and 4 wk after intake of the test beverages for the measurement of plasma lipids. Plasma oxidized LDL concentrations decreased in the low-, middle-, and high-cocoa groups compared with baseline. A stratified analysis was performed on 131 subjects who had a LDL cholesterol concentrations of > or =3.23 mmol/L at baseline. In these subjects, plasma LDL cholesterol, oxidized LDL, and apo B concentrations decreased, and the plasma HDL cholesterol concentration increased, relative to baseline in the low-, middle-, and high-cocoa groups. The results suggest that polyphenolic substances derived from cocoa powder may contribute to a reduction in LDL cholesterol, an elevation in HDL cholesterol, and the suppression of oxidized LDL.     

Improving the prediction of cardiovascular risk: interaction between LDL and HDL cholesterol

BACKGROUND: The ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol (or the ratio of low-density lipoprotein [LDL] to HDL) is currently advocated to estimate the coronary risk associated with LDL and HDL cholesterol levels. METHODS: We analyzed the relation between LDL and HDL cholesterol levels to predict the risk of future coronary events. Using data from the Lipid Research Clinics Follow-up Cohort, we developed multivariate equations to predict coronary deaths among 4684 men and women followed for approximately 12 years. We used these equations to compare the predictive power of the LDL/HDL ratio with the independent effects of LDL and HDL and an LDL-HDL interaction term. We then used each model to forecast the 10-year risk of coronary death based on various lipid levels after adjustment for conventional risk factors (eg, blood pressure, gender, cigarette smoking). RESULTS: Levels of LDL and HDL and the interaction between them are all independent risk factors for coronary death. The benefits of increasing HDL are strongest among persons with high LDL. Conversely, the benefits of decreasing LDL are greatest among those with low HDL. We confirmed these observations in a published dataset showing the effects of treatment of hyperlipidemia. Predictions of benefits of treatment that were based on interaction of LDL and HDL were more accurate than predictions without interaction. CONCLUSIONS: The LDL/HDL ratio alone may not fully capture the complex interaction between LDL and HDL and the relation of each to coronary risk.     

Soy isoflavone intake lowers serum LDL cholesterol: a meta-analysis of 8 randomized controlled trials in humans

Clinical trials have noted hypocholesterolemic effects of soy protein intake, but the components responsible are not known. This meta-analysis of 8 randomized controlled trials was conducted to more precisely evaluate the effects of isoflavones on blood LDL cholesterol concentration independently of soy protein level. PubMed was searched for English-language "randomized controlled trial" articles published from 1966 to 2003 that described the effects of soy protein isolate (SPI) intake with measured isoflavone levels on blood lipids in humans using the search terms "soy protein," "isoflavones," and "cholesterol." From 31 articles identified by the search, 8 articles (with 10 low vs. high isoflavone comparisons) were selected for the meta-analysis. Subjects in each comparison consumed similar dietary fat, cholesterol, and fiber; the reported body weight of subjects did not change significantly during treatment. Serum LDL cholesterol concentration in subjects who consumed SPI (mean 50 g/d) with high isoflavone content (mean intake 96 mg/d) decreased by 0.15 mmol/L (95% CI: 0.08 to 0.23 mmol/L; P < 0.0001) compared with those who consumed the same SPI level with low isoflavone content (mean intake 6 mg/d). Decreases in serum LDL cholesterol concentration in hypercholesterolemic and normocholesterolemic subjects were 0.18 mmol/L (95% CI: 0.01 to 0.35 mmol/L; P = 0.03) and 0.14 mmol/L (95% CI: 0.06, 0.23 mmol/L; P = 0.0008), respectively. With identical soy protein intake, high isoflavone intake led to significantly greater decreases in serum LDL cholesterol than low isoflavone intake, demonstrating that isoflavones have LDL cholesterol-lowering effects independent of soy protein.     

Maintenance of the LDL cholesterol:HDL cholesterol ratio in an elderly population given a dietary cholesterol challenge

We previously evaluated the responses to dietary cholesterol in children and young adults. In this study, the effects of dietary cholesterol on plasma lipids and LDL atherogenicity were evaluated in 42 elderly subjects (29 postmenopausal women and 13 men > 60 y old). Our exclusion criteria were diabetes, heart disease, and the use of reductase inhibitors. The study followed a randomized crossover design in which subjects were assigned to consume the equivalent of 3 large eggs (EGG) daily or the same amount of a cholesterol-free, fat-free egg substitute (SUB) for a 1-mo period. After a 3-wk washout period, subjects were assigned to the alternate treatment. The concentration of plasma cholesterol after the EGG period varied among subjects. When all subjects were evaluated, there were significant increases in LDL cholesterol (LDL-C) (P < 0.05) and HDL-C (P < 0.001) for both men and women during the EGG period, resulting in no alterations in the LDL-C:HDL-C or the total cholesterol:HDL-C ratios. In addition, the LDL peak diameter was increased during the EGG period for all subjects. In contrast, the measured parameters of LDL oxidation, conjugated diene formation, and LDL lag time did not differ between the EGG and the SUB periods. We conclude from this study that dietary cholesterol provided by eggs does not increase the risk for heart disease in a healthy elderly population.     

Long-term consumption of a raw food diet is associated with favorable serum LDL cholesterol and triglycerides but also with elevated plasma homocysteine and low serum HDL cholesterol in humans

High consumption of vegetables and fruits is associated with reduced risk for cardiovascular disease. However, little information is available about diets based predominantly on consumption of fruits and their health consequences. We investigated the effects of an extremely high dietary intake of raw vegetables and fruits (70-100% raw food) on serum lipids and plasma vitamin B-12, folate, and total homocysteine (tHcy). In a cross-sectional study, the lipid, folate, vitamin B-12, and tHcy status of 201 adherents to a raw food diet (94 men and 107 women) were examined. The participants consumed approximately 1500-1800 g raw food of plant origin/d mainly as vegetables or fruits. Of the participants, 14% had high serum LDL cholesterol concentrations, 46% had low serum HDL cholesterol, and none had high triglycerides. Of raw food consumers, 38% were vitamin B-12 deficient, whereas 12% had an increased mean corpuscular volume (MCV). Plasma tHcy concentrations were correlated with plasma vitamin B-12 concentrations (r = -0.450, P < 0.001), but not with plasma folate. Plasma tHcy and MCV concentrations were higher in those in the lowest quintile of consumption of food of animal origin (P(trend) < 0.001). This study indicates that consumption of a strict raw food diet lowers plasma total cholesterol and triglyceride concentrations, but also lowers serum HDL cholesterol and increases tHcy concentrations due to vitamin B-12 deficiency.     

Dietary cholesterol from eggs increases the ratio of total cholesterol to high-density lipoprotein cholesterol in humans: a meta-analysis

BACKGROUND: Several epidemiologic studies found no effect of egg consumption on the risk of coronary heart disease. It is possible that the adverse effect of eggs on LDL-cholesterol is offset by their favorable effect on HDL cholesterol. OBJECTIVE: The objective was to review the effect of dietary cholesterol on the ratio of total to HDL cholesterol. DESIGN: Studies were identified by MEDLINE and Biological Abstracts searches (from 1974 to June 1999) and by reviewing reference lists. In addition, we included data from a more recently published study. Studies were included if they had a crossover or parallel design with a control group, if the experimental diets differed only in the amount of dietary cholesterol or number of eggs and were fed for > or =14 d, and if HDL-cholesterol concentrations were reported. Of the 222 studies identified, 17 studies involving 556 subjects met these criteria. RESULTS: The addition of 100 mg dietary cholesterol/d increased the ratio of total to HDL cholesterol by 0.020 units (95% CI: 0.010, 0.030), total cholesterol concentrations by 0.056 mmol/L (2.2 mg/dL) (95% CI: 0.046, 0.065 mmol/L; 1.8, 2.5 mg/dL), and HDL-cholesterol concentrations by 0.008 mmol/L (0.3 mg/dL) (95% CI: 0.005, 0.010 mmol/L; 0.2, 0.4 mg/dL). CONCLUSIONS: Dietary cholesterol raises the ratio of total to HDL cholesterol and, therefore, adversely affects the cholesterol profile. The advice to limit cholesterol intake by reducing consumption of eggs and other cholesterol-rich foods may therefore still be valid.     

Lupin protein compared to casein lowers the LDL cholesterol:HDL cholesterol-ratio of hypercholesterolemic adults

Background  

Lupin protein had hypocholesterolemic effects in laboratory animals. However, the effect in humans has not been elucidated till now.     

The LDL to HDL cholesterol ratio as a valuable tool to evaluate coronary heart disease risk

The current National Cholesterol Education Program Adult Treatment Panel III guidelines recommend specific target levels of LDL cholesterol (LDL-C) and HDL cholesterol (HDL-C) for determining cardiovascular disease (CVD) risk and evaluating the effectiveness of lipid-lowering therapies. While there is a growing consensus that levels of apolipoprotein (apo) B and the ratio of apo B/apo A-I are more accurate predictors of CVD risk, the question has been raised as to whether it is realistic to expect patients and health professionals to switch from cholesterol-based guidelines to apolipoprotein-based guidelines. Because it will take time before apolipoprotein terminology is recognized by the general public and recommended by the NCEP Adult Treatment panel to evaluate risk, it may be more efficacious to continue adhering to the already familiar and proven measurements of the LDL-C/HDL-C ratio. The following review provides evidence that the LDL-C/HDL-C ratio continues to be a valuable and standard tool to evaluate CVD risk in all populations.     

Fasting increases serum total cholesterol, LDL cholesterol and apolipoprotein B in healthy, nonobese humans.

Voluntary fasting is practiced by many humans in an attempt to lose body weight. Conflicting results have been published on the effects of food deprivation on serum lipids. To study the effect of acute starvation on serum lipids, 10 nonobese (93-124% of ideal body weight), healthy adults (6 men, 4 women, 21-38 y old) fasted (no energy) for 7 d. Fasting increased total serum cholesterol from 4.90 +/- 0.23 to 6.73 +/- 0.41 mmol/L (37.3 +/- 5.0%; P < 0.0001) and LDL cholesterol from 2.95 +/- 0.21 to 4.90 +/- 0.36 mmol/L (66.1 +/- 6. 6%; P < 0.0001). Serum apolipoprotein B (apo B) increased from 0.84 +/- 0.06 to 1.37 +/- 0.11 g/L (65.0 +/- 9.2%; P < 0.0001). The increases in serum cholesterol, LDL and apo B were associated with weight loss. Fasting did not affect serum concentrations of triacylglycerol and HDL cholesterol. Serum concentrations of insulin-like growth factor-I (IGF-I) decreased from 246 +/- 29 (prefast) to 87 +/- 10 microg/L after 1 wk of fasting (P < 0.0001). We conclude that, in nonobese subjects, fasting is accompanied by increases in serum cholesterol, LDL and apo B concentrations, whereas IGF-I levels are decreased.     

Dietary intakes of flavonols, flavones and isoflavones by Japanese women and the inverse correlation between quercetin intake and plasma LDL cholesterol concentration

The intake of flavonols, flavones and isoflavones by Japanese women was calculated from our food-phytochemical composition table. The relationship between intake of these phytochemicals and various anthropometric and blood chemistry data was analyzed in a cross-sectional study. The subjects were 115 women volunteers, aged 29-78 y, living in the northern part of Japan. Each subject completed a 3-d dietary record and received a health check up, including urine and blood sampling for biochemical analysis. Total mean intakes of flavonoids (sum of flavonols and flavones) and isoflavones were 16.7 and 47.2 mg/d, respectively. The major source of flavonoids was onions (45.9%) and that of isoflavones was tofu (37.0%). Total intake of isoflavones exceeded that of other dietary antioxidants, such as flavonoids, carotenoids (3.5 mg/d) and vitamin E (8.2 mg/d), and was approximately one half of the vitamin C intake (109 mg/d). The total intake of flavonoids was inversely correlated with the plasma total cholesterol concentration (TC) (r = -0.236, P: < 0.05) and plasma LDL cholesterol concentration (LDL-C) (r = -0.220, P: < 0.05), after the adjustment for age, body mass index and total energy intake. As a single component, quercetin was inversely correlated with both TC (r = -0.261, P: < 0.01) and LDL-C (r = -0. 263, P: < 0.01). Among Japanese, flavonoid and isoflavone intake is the main component among nonnutrient phytochemicals with antioxidant potential in the diet. These results suggest that a high consumption of both flavonoids and isoflavones by Japanese women may contribute to their low incidence of coronary heart disease compared with women in other countries.     

LDL cholesterol: its regulation and manipulation

Elevated plasma LDL cholesterol concentrations result primarily from two mechanisms: LDL overproduction and loss of hepatic receptor-dependent LDL removal. This knowledge can be used to lower plasma cholesterol and thereby retard or even reverse atherosclerosis. Pharmacologic agents are useful, as are dietary approaches.     

Phytosterols/stanols lower cholesterol concentrations in familial hypercholesterolemic subjects: a systematic review with meta-analysis

BACKGROUND: To-date, reviews regarding the cholesterol lowering capacity of phytosterols/stanols have focused on normo- and hypercholesterolemic (HC) subjects. Familial hypercholestrolemia (FH) is characterized by very high low-density lipoprotein cholesterol (LDL-C) concentrations and is considered a world public health problem due to the high incidence of premature coronary heart disease (CHD) in these patients. OBJECTIVE: To conduct a systematic review that investigates the efficacy of phytosterols/stanols in lowering total cholesterol (TC) and LDL-C concentrations in FH subjects. DESIGN: Randomized controlled intervention trials with the primary objective to investigate the effects of phytosterols/stanols on lipid concentrations in FH subjects were identified through selected international journal databases and reference lists of relevant publications. Two researchers extracted data from each identified trial and only trials of sufficient quality (e.g. controlled, randomized, double-blind, good compliance, sufficient statistical power) were included in the review. The main outcome measures were differences between treatment and control groups for LDL-C, TC, high-density lipoprotein cholesterol (HDL-C) and triacylglycerol (TG). RESULTS: Six out of 13 studies were of sufficient quality. Two were excluded from the meta-analysis because the sterols were administered in the granulate form at very high dosages (12 g/day and 24 g/day) compared to the other studies that used fat spreads as vehicle with dosages ranging from 1.6-2.8 g/day. The subjects were heterozygous, aged 2-69 years with baseline TC and LDL-C concentrations of +/-7 mmol/L and +/-5.4 mmol/L, respectively. The duration of the studies ranged from 4 weeks to 3 months. Fat spreads enriched with 2.3 +/- 0.5 g phytosterols/stanols per day significantly reduced TC from 7 to 11% with a mean decrease of 0.65 mmol/L [95% CI -0.88, -0.42 mmol/L], p < 0.00001 and LDL-C from 10-15% with a mean decrease of 0.64 mmol/L [95% CI -0.86, -0.43 mmol/L], p < 0.00001 in 6.5 +/- 1.9 weeks compared to control treatment, without any adverse effects. TG and HDL-C concentrations were not affected. CONCLUSION: Phytosterols/stanols may offer an effective adjunct to the cholesterol lowering treatment strategy of FH patients.     

An isoenergetic very low carbohydrate diet improves serum HDL cholesterol and triacylglycerol concentrations,the total cholesterol to HDL cholesterol ratio and postprandial pipemic responses compared with a low fat diet in normal weight,normolipidemic women

Very low carbohydrate diets are popular, yet little is known about their effects on blood lipids and other cardiovascular disease risk factors. We reported previously that a very low carbohydrate diet favorably affected fasting and postprandial triacylglycerols, LDL subclasses and HDL cholesterol (HDL-C) in men but the effects in women are unclear. We compared the effects of a very low carbohydrate and a low fat diet on fasting lipids, postprandial lipemia and markers of inflammation in women. We conducted a balanced, randomized, two-period, crossover study in 10 healthy normolipidemic women who consumed both a low fat (<30% fat) and a very low carbohydrate (<10% carbohydrate) diet for 4 wk each. Two blood draws were performed on separate days at 0, 2 and 4 wk and an oral fat tolerance test was performed at baseline and after each diet period. Compared with the low fat diet, the very low carbohydrate diet increased (P 相似文献