The effect of chlorogenic acid on blood pressure: a systematic review and meta-analysis of randomized clinical trials.

Several dietary supplements are currently marketed for management of hypertension, but the evidence for effectiveness is conflicting. Our objective was to critically appraise and evaluate the evidence for the effectiveness of chlorogenic acids (CGAs) on blood pressure, using data from published randomized clinical trials (RCTs). Electronic searches were conducted in Medline, Embase, Amed, Cinahl and The Cochrane Library. We also hand-searched the bibliographies of all retrieved articles. Two reviewers independently determined the eligibility of studies and extracted the data. The reporting quality of all included studies was assessed by the use of a quality assessment checklist adapted from the Consolidated Standard of Reporting Trials Statement. Disagreements were resolved through discussion. Seven eligible studies were identified, and five including 364 participants were included. There were variations in the reporting quality of the included RCTs. Meta-analysis revealed a statistically significant reduction in systolic blood pressure in favour of CGA (mean difference (MD): -4.31 mm Hg; 95% confidence interval (CI): -5.60 to -3.01; I(2)=65%; P<0.00001). Meta-analysis also showed a significant reduction in diastolic blood pressure favouring CGA (MD: -3.68 mm Hg; 95% CI: -3.91 to -3.45; I(2)=97%; P<0.00001). All studies reported no adverse events. In conclusion, the evidence from published RCTs suggests that CGA intake causes statistically significant reductions in systolic and diastolic blood pressures. The size of the effect is moderate. Few clinical trials have been conducted; they vary in design and methodology and are confined to Asian populations and funded by CGA manufacturers. Large independent trials evaluating the effects of CGA on blood pressure are warranted.

Dietary beta-carotene, vitamin C and E intake and breast cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC).

So far, studies on dietary antioxidant intake, including beta-carotene, vitamin C and vitamin E, and breast cancer risk are inconclusive. Thus, we addressed this question in the European Prospective Investigation into Cancer and Nutrition. During a median follow-up time of 8.8 years, 7,502 primary invasive breast cancer cases were identified. Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI). All analyses were run stratified by menopausal status at recruitment and, additionally, by smoking status, alcohol intake, use of exogenous hormones and use of dietary supplements. In the multivariate analyses, dietary intake of beta-carotene, vitamin C and E was not associated with breast cancer risk in premenopausal [highest vs. lowest quintile: HR, 1.04 (95% CI, 0.85-1.27), 1.12 (0.92-1.36) and 1.11 (0.84-1.46), respectively] and postmenopausal women [0.93 (0.82-1.04), 0.98 (0.87-1.11) and 0.92 (0.77-1.11), respectively]. However, in postmenopausal women using exogenous hormones, high intake of beta-carotene [highest vs. lowest quintile; HR 0.79 (95% CI, 0.66-0.96), P (trend) 0.06] and vitamin C [0.88 (0.72-1.07), P (trend) 0.05] was associated with reduced breast cancer risk. In addition, dietary beta-carotene was associated with a decreased risk in postmenopausal women with high alcohol intake. Overall, dietary intake of beta-carotene, vitamin C and E was not related to breast cancer risk in neither pre- nor postmenopausal women. However, in subgroups of postmenopausal women, a weak protective effect between beta-carotene and vitamin E from food and breast cancer risk cannot be excluded.

Use of dietary supplements in the European Prospective Investigation into Cancer and Nutrition calibration study.

BACKGROUND: Dietary supplement use is increasing, but there are few comparable data on supplement intakes and how they affect the nutrition and health of European consumers. The aim of this study was to describe the use of dietary supplements in subsamples of the 10 countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS: Specific questions on dietary supplement use were asked as a part of single 24-h recalls performed on 36,034 men and women aged 35-74 years from 1995 to 2000. RESULTS: Between countries, the mean percentage of dietary supplement use varied almost 10-fold among women and even more among men. There was a clear north-south gradient in use, with a higher consumption in northern countries. The lowest crude mean percentage of use was found in Greece (2.0% among men, 6.7% among women), and the highest was in Denmark (51.0% among men, 65.8% among women). Use was higher in women than in men. Vitamins, minerals or combinations of them were the predominant types of supplements reported, but there were striking differences between countries. CONCLUSIONS: This study indicates that there are wide variations in supplement use in Europe, which may affect individual and population nutrient intakes. The results underline the need to monitor consumption of dietary supplements in Europe, as well as to evaluate the risks and benefits.

Plasma phyto-oestrogens and prostate cancer in the European Prospective Investigation into Cancer and Nutrition.

We examined plasma concentrations of phyto-oestrogens in relation to risk for subsequent prostate cancer in a case-control study nested in the European Prospective Investigation into Cancer and Nutrition. Concentrations of isoflavones genistein, daidzein and equol, and that of lignans enterolactone and enterodiol, were measured in plasma samples for 950 prostate cancer cases and 1042 matched control participants. Relative risks (RRs) for prostate cancer in relation to plasma concentrations of these phyto-oestrogens were estimated by conditional logistic regression. Higher plasma concentrations of genistein were associated with lower risk of prostate cancer: RR among men in the highest vs the lowest fifth, 0.71 (95% confidence interval (CI) 0.53-0.96, P trend=0.03). After adjustment for potential confounders this RR was 0.74 (95% CI 0.54-1.00, P trend=0.05). No statistically significant associations were observed for circulating concentrations of daidzein, equol, enterolactone or enterodiol in relation to overall risk for prostate cancer. There was no evidence of heterogeneity in these results by age at blood collection or country of recruitment, nor by cancer stage or grade. These results suggest that higher concentrations of circulating genistein may reduce the risk of prostate cancer but do not support an association with plasma lignans.