Search

A study was conducted to examine the effect of supplemental fish oil versus placebo on ventricular tachyarrhythmia or death. The results obtained do not indicate evidence of a strong protective effect of intake of omega-3 polyunsaturated fatty acids (PUFAs) from fish oil against ventricular tachyarrhythmia in patients with implantable cardioverter defibrillators.

Mensink and Katan showed in 1990 that trans fats reduce high-and increase low-density lipoprotein cholesterol. Unilever aided this study because the company considered knowledge on trans fats incomplete in spite of their long history of safe use. The decision in 1994 to remove trans fats from Unilever's retail spreads was triggered by media events, but it was built on a solid understanding of the nutritional and technological aspects of trans fats. Over the next 14 years, manufacturers worldwide followed suit. This experience illustrates that food companies need to know about the health effects of their products and how to apply that knowledge. Key words: trans fat, coronary heart disease, margarine, history, industry

The evidence of physiological and cellular effects of trans fatty acids, and the relations between the intake of these acids and coronary heart disease (CHD) is reviewed. The results of several experiments with trans fatty acids revealed that consumption of trans fatty acids provides no apparent nutritional benefit and has considerable potential to cause harm or even lead to CHD.

In contrast to most expectations, we showed previously that dietary fructooligosaccharides (FOS) stimulate intestinal colonization and translocation of invasive Salmonella enteritidis in rats. Even before infection, FOS increased the cytotoxicity of fecal water, mucin excretion, and intestinal permeability. In the present study, we tested whether FOS has these effects in humans. A double-blind, placebo-controlled, crossover study of 2 x 2 wk, with a washout period of 2 wk, was performed with 34 healthy men. Each day, subjects consumed lemonade containing either 20 g FOS or placebo and the intestinal permeability marker chromium EDTA (CrEDTA). On the last 2 d of each supplement period, subjects scored their gastrointestinal complaints on a visual analog scale and collected feces and urine for 24 h. Fecal lactic acid was measured using a colorimetric enzymatic kit. The cytotoxicity of fecal water was determined with an in vitro bioassay, fecal mucins were quantified fluorimetrically, and intestinal permeability was determined by measuring urinary CrEDTA excretion. In agreement with our animal studies, FOS fermentation increased fecal wet weight, bifidobacteria, lactobacilli, and lactic acid. Consumption of FOS increased flatulence and intestinal bloating. In addition, FOS consumption doubled fecal mucin excretion, indicating mucosal irritation. However, FOS did not affect the cytotoxicity of fecal water and intestinal permeability. The FOS-induced increase in mucin excretion in our human study suggests mucosal irritation in humans, but the overall effects are more moderate than those in rats. KEY WORDS: * fructooligosaccharides * humans * microflora * mucin * prebiotics

Diets high in red meat and low in green vegetables are associated with an increased risk of colon cancer. In rats, dietary heme, mimicking red meat, increases colonic cytotoxicity and proliferation of the colonocytes, whereas addition of chlorophyll from green vegetables inhibits these heme-induced effects. Chlorophyllin is a water-soluble hydrolysis product of chlorophyll that inhibits the toxicity of many planar aromatic compounds. The present study investigated whether chlorophyllins could inhibit the heme-induced luminal cytotoxicity and colonic hyperproliferation as natural chlorophyll does. Rats were fed a purified control diet, the control diet supplemented with heme, or a heme diet with 1.2 mmol/kg diet of chlorophyllin, copper chlorophyllin, or natural chlorophyll for 14 d (n = 8/group). The cytotoxicity of fecal water was determined with an erythrocyte bioassay and colonic epithelial cell proliferation was quantified in vivo by [[methyl-.sup.3]H]thymidine incorporation into newly synthesized DNA. Exfoliation of colonocytes was measured as the amount of rat DNA in feces using quantitative PCR analysis. Heme caused a >50-fold increase in the cytotoxicity of the fecal water, a nearly 100% increase in proliferation, and almost total inhibition of exfoliation of the colonocytes. Furthermore, the addition of heme increased TBARS in fecal water. Chlorophyll, but not the chlorophyllins, completely prevented these heme-induced effects. In conclusion, inhibition of the heme-induced colonic cytotoxicity and epithelial cell turnover is specific for natural chlorophyll and cannot be mimicked by water-soluble chlorophyllins. J. Nutr. 135: 1995-2000, 2005. KEY WORDS: * diet * red meat * green vegetables * prevention * colon cancer

Unfiltered coffee brews such as French press and espresso contain a lipid from coffee beans named cafestol that raises serum cholesterol in humans. Cafestol decreases the expression and activity of cholesterol 7[alpha]-hydroxylase, the rate-limiting enzyme in the classical pathway of bile acid synthesis, in cultured rat hepatocytes and livers of APOE3 Leiden mice. Inhibition of bile acid synthesis has been suggested to be responsible for the cholesterol-raising effect of cafestol. Therefore, we assessed whether cafestol decreases the activity of cholesterol 7[alpha]-hydroxylase in humans. Because liver biopsies were not feasible, we measured plasma levels of 7[alpha]-hydroxy4-cholesten-3-one, a marker for the activity of cholesterol 7[alpha]-hydroxylase in the liver. Plasma 7[alpha]-hydroxy-4cholesten-3-one was measured in 2 separate periods in which healthy volunteers consumed coffee oil containing cafestol (69 mg/d) for 5 wk. Plasma levels of 7[alpha]-hydroxy-4-cholesten-3-one increased by 47 [+ or -] 13% (mean [+ or -] SEM, n = 38, P = 0.001)in the first period and by 23 + 10% (n = 31, P = 0.03)in the second treatment period. Serum cholesterol was raised by 23 [+ or -] 2% (P < 0.001) in the first period and by 18 [+ or -] 2% (P < 0.001) in the second period. We corrected individual 7[alpha]-hydroxy-4-cholesten-3-one levels for serum cholesterol levels, because coffee oil increases serum cholesterol and 7[alpha]-hydroxy-4-cholesten-3-one is probably present in the lipoprotein fraction of serum. After correction, the increase in 7[alpha]-hydroxy-4-cholesten-3-one was 24 [+ or -] 11% (P = 0.04) in the first period and there was no effect in period 2. Our study showed that coffee oil did not decrease, and actually increased, plasma levels of 7[alpha]-hydroxy-4-cholesten-3-one in humans in 2 separate treatment periods. Therefore, this study does not support the hypothesis that cafestol decreases bile acid synthesis in humans. KEY WORDS: * coffee oil * cafestol * cholesterol * bile acid synthesis

The response of plasma lipids to dietary cholesterol and fat varies among individuals. Variations in genes involved in cholesterol metabolism can be important in these interindividual differences. The rate-limiting enzyme in the conversion of cholesterol into bile acids is cholesterol 7[alpha]-hydroxylase (CYP7A1). We investigated the effect of the A278-C promoter polymorphism in the CYP7A1 gene on responses of plasma lipids to an increased intake in dietary cholesterol (742 [+ or -] 114 mg/d), cafestol (57 [+ or -] 6 mg/d), saturated fat [change of 8-9 energy percent/d (en%/d)] and trans fat (change of 10-11 en%/d) in 496 normolipidemic subjects. These responses were measured in 26 previously published dietary trials. After adjustment for the apolipoprotein E genotype effect, AA-subjects consuming a cholesterol-rich diet had a smaller increase in plasma HDL cholesterol than CC-subjects (0.00 [+ or -] 0.02 vs. 0.17 [+ or -] 0.04 mmol/L; P < 0.001). Upon intake of cafestol, AA-subjects had a smaller increase in plasma total cholesterol than CC-subjects (0.69 [+ or -] 0.10 vs. 1.01 [+ or -] 0.10 mmol/L; P = 0.028). No effects of the polymorphism were found in the saturated and trans fat interventions. In conclusion, the CYP7A1 polymorphism has a small but significant effect on the increase in plasma HDL cholesterol and plasma total cholesterol after an increased intake of dietary cholesterol and cafestol, respectively. KEY WORDS: * CYP7A1 * polymorphism * cholesterol * cafestol * dietary interventions

The objective of this meta-analysis was to estimate quantitatively the associations between intake of [alpha]-linolenic acid [ALA, the (n-3) fatty acid in vegetable oils], mortality from heart disease, and the occurrence of prostate cancer in observational studies. We identified 5 prospective cohort studies that reported intake of ALA and mortality from heart disease. We also reviewed data from 3 clinical trials on ALA intake and heart disease, in addition, we identified 9 cohort and case-control studies that reported on the association between ALA intake or blood levels and incidence or prevalence of prostate cancer. We combined risk estimates across studies using a random-effects model. High ALA intake was associated with reduced risk of fatal heart disease in prospective cohort studies (combined relative risk 0.79, 95% CI 0.60-1.04). Three open-label trials also indicated that ALA may protect against heart disease. However, epidemiologic studies also showed an increased risk of prostate cancer in men with a high intake or blood level of ALA (combined relative risk 1.70; 95% CI 1.12-2.58). This meta-analysis shows that consumption of ALA might reduce heart disease mortality. However, the association between high intake of ALA and prostate cancer is of concern and warrants further study. KEY WORDS: * linolenic acid * (n-3) fatty acids * cardiovascular * prostate cancer * meta-analysis

Dietary phenols are antioxidants, and their consumption might contribute to the prevention of cardiovascular disease. Coffee and tea are major dietary sources of phenols. Dietary phenols are metabolized extensively in the body. Lack of quantitative data on their metabolites hinders a proper evaluation of the potential biological effects of dietary phenols in vive. The aim of this study was to identify and quantify the phenolic acid metabolites of chlorogenic acid (major phenol in coffee), quercetin-3-rutinoside (major flavonol in tea) and black tea phenols in humans, and determine the site of metabolism. Healthy humans (n = 20) with an intact colon participated in a dietary controlled crossover study, and we identified and quantified ~60 potential phenolic acid metabolites in urine. Half of the ingested chlorogenic acid and 43% of the tea phenols were metabolized to hippuric acid. Quercetin-3-rutinoside was metabolized mainly to phenylacetic acids, i.e., 3-hydroxyphenylacetic acid (36%), 3-methoxy-4-hydroxyphenylacetic acid (8%) and 3,4-dihydroxyphenylacetic acid (5%). In contrast, in seven humans without a colon, we found only traces of phenolic acid metabolites in urine after they had ingested chlorogenic acid and quercetin-3-rutinoside. This implies that the colonic microflora convert most of these dietary phenols into metabolites that then reach the circulation. Metabolites of dietary phenols have lower antioxidant activity than their parent compounds; therefore, the contribution of dietary phenols to antioxidant activity in vive might be lower than expected from in vitro tests. J. Nutr. 133: 1806-1814, 2003. KEY WORDS: * chlorogenicacid * quercetin, black tea * metabolism, humans

Elevated levels of plasma total homocysteine are associated with a higher risk of cardiovascular disease. Betaine and 5-methyltetrahydrofolate can remethylate homocysteine into methionine via independent reactions. We determined the effect of daily betaine supplementation, compared with both folic acid and placebo, on plasma concentrations of total homocysteine after an overnight fast and after methionine loading in men and women with mildly elevated homocysteine. Groups of twelve subjects ingested 6 g betaine, 800 [micro]g folic acid with 6 g placebo or 6 g placebo each day for 6 wk. A methionine-loading test (i.e., ingestion of 100 mg L-methionine/kg body mass) was performed before and after 6 wk of supplementation. Fasting plasma homocysteine decreased by 1.8 [micro]mol/L (95% confidence interval [CI]: -3.6, 0.0, P < 0.05) in the betaine group and by 2.7 [micro]mol/L (95% CI: -4.5, -0.9, P < 0.05) in the folic acid group. These changes are relative to the change in the placebo group, in which fasting plasma homocysteine rose by 0.5 [micro]mol/L. Furthermore, betaine suppressed the total area under the plasma homocysteine-time curve after methionine loading by 221 [micro]mol * 24 h/L (95% CI: -425, -16, P < 0.05) compared with placebo, whereas folic acid had no effect. In conclusion, betaine appears to be highly effective in preventing a rise in plasma homocysteine concentration after methionine intake in subjects with mildly elevated homocysteine. It is not known whether this potential of betaine to 'stabilize' circulating homocysteine concentrations lowers the risk of cardiovascular disease. KEY WORDS: * homocysteine metabolism * betaine * folic acid * methionine-loading test * intervention study

(n-3) Fatty acids may reduce the risk of sudden death by preventing life-threatening cardiac arrhythmia. A standard electrocardiogram (ECG) may be used to detect clues as to the mechanism by which (n-3) fatty acids affect the electrophysiology of the heart. An earlier study showed that (n-3) fatty acids decreased the duration of the heart-rate corrected QT interval (QTc) in dogs. However, effects of (n-3) fatty acids on the standard ECG of humans have not been reported. Therefore, we investigated the effect of (n-3) fatty acids on QTc, QRS duration, apex-to-end-T duration, T-loop morphology and spatial QRS-T angle in apparently healthy men and women aged 50 to 70 y. Subjects (n = 42/group) received either capsules providing 1.5 g (n-3) fatty acids daily or placebo for 12 wk. ECG were recorded before and after intervention. None of the ECG characteristics were affected by (n-3) fatty acids. The QTc decreased by 0.8 ms or 0.2% (95% confidence interval, -6.1 to 4.4 ms) in subjects that consumed (n-3) fatty acids compared with the placebo group. These results do not support the hypothesis that (n-3) fatty acids prevent arrythmia through electrophysiologic effects on heart cell membranes. However, an effect on the ECG in more susceptible populations can not be excluded. J. Nutr. 132: 3051--3054, 2002. KEY WORDS: * (n-3) fatty acids * ventricular arrhythmias * electrocardiogram * QTc interval * electrophysiology

Objective To determine flavonoid content of US foods, mean individual intakes, major food sources, and associations with other nutrients. Subjects US men (n=37,886) and women (n=78,886) who completed a semiquantitative food frequency questionnaire in 1990. Design Men and women completed a questionnaire that listed 132 items, including onions as a garnish and as a vegetable, rings, or soup. Foods known to be important sources of flavonols (quercetin, myricetin, and kaempferol) and flavones (luteolin and apigenin) were analyzed biochemically. The database contained values from the analyzed foods, previously published values from Dutch foods, and imputed values. Statistics Means and standard deviations, contributions of foods to summed intake of each flavonoid, and Pearson correlation coefficients were calculated. Results Of the flavonols and flavones studied, quercetin contributed 73% in women and 76% in men. The mean flavonol and flavone intake was approximately 20 to 22 mg per day. Onions, tea, and apples contained the highest amounts of flavonols and flavones. Correlations between the intakes of flavonols and flavones and intakes of beta carotene, vitamin E, vitamin C, folic acid, and dietary fiber did not exceed 0.35. Conclusion Although flavonols and flavones are subgroups of flavonoids hypothesized to be associated with reduced risk of coronary heart disease, data on flavonoid intake has been limited due to the lack of food composition data. Nutrition professionals can use these and other published data to estimate intake of flavonoids in their populations. This work should facilitate the investigation of this class of dietary antioxidants as a contributor to disease prevention., Flavonoids are minor constituents of a wide variety in plants. Their structure includes two phenolic benzene rings linked by a heterocyclic pyrone or pyran ring containing an oxygen atom. They [...]

Animal and in vitro studies suggest that olive oil phenols are effective antioxidants. The most abundant phenols in olive oil are the nonpolar oleuropein- and ligstroside-aglycones and the polar hydroxytyrosol and tyrosol. The aim of this study was to gain more insight into the metabolism of those phenols in humans. We measured their absorption in eight healthy ileostomy subjects. We also measured urinary excretion in the ileostomy subjects and in 12 volunteers with a colon. Subjects consumed three different supplements containing 100 mg of olive oil phenols on separate days in random order. Ileostomy subjects consumed a supplement with mainly nonpolar phenols, one with mainly polar phenols and one with the parent compound oleuropein-glycoside. Subjects with a colon consumed a supplement without phenols (placebo) instead of the supplement with oleuropein-glycoside. Ileostomy effluent and urine were collected for 24 h after supplement intake. Tyrosol and hydroxytyrosol concentrations were low (< 4 mol/100 mol of intake) in the ileostomy effluent, and no aglycones were detected. We estimated that the apparent absorption of phenols was at least 55-66% of the ingested dose. Absorption was confirmed by the excretion of tyrosol and hydroxytyrosol in urine. In ileostomy subjects, 12 mol/100 mol and in subjects with a colon, 6 mol/100 mol of the phenols from the nonpolar supplement were recovered in urine as tyrosol or hydroxytyrosol. In both subject groups, 5-6 mol/100 mol of the phenols was recovered from the polar supplement. When ileostomy subjects were given oleuropein-glycoside, 16 mol/100 mol was recovered in 24-h urine, mainly in the form of hydroxytyrosol. Thus, humans absorb a large part of ingested olive oil phenols and absorbed olive oil phenols are extensively modified in the body. KEY WORDS: * phenols * olive oil * absorption * ileostomy * humans

Research has been conducted on the health effects of trans fatty acids. Results indicate that the reduction of trans fatty acid consumption can prevent or treat cardiovascular diseases.

The food industry could help lower the rate of coronary heart disease by replacing trans fatty acids with unhydrogenated fats. Trans fatty acids are unsaturated fats that are partially hydrogenated to create solid forms of fat such as stick margarine. However, they have been linked to coronary heart disease. While some manufacturers now make margarine that is free of trans fatty acids, trans fatty acids also occur in baked goods and fast foods. But there is no requirement to include that information on the label.