Effects of phytoestrogen supplementation on intermediate cardiovascular disease risk factors among postmenopausal women: a meta-analysis of randomized controlled trials.

IMPORTANCE: Phytoestrogens are becoming popular constituents of human diets and are increasingly used by postmenopausal women. OBJECTIVE: Our study aims to determine the effects of phytoestrogen supplementation on intermediate cardiovascular disease (CVD) risk factors in postmenopausal women. EVIDENCE REVIEW: Five electronic databases (Medline, EMBASE, Web of Science, Cochrane CENTRAL, Google Scholar) were systematically searched to identify eligible studies, that is, randomized controlled trials (RCTs) that assessed the association of phytoestrogen supplementation with CVD risk factors (serum lipids, homocysteine, fibrinogen, markers of inflammation, oxidative stress and endothelial function, carotid intima-media thickness [CIMT]) in postmenopausal women. Data were extracted by two independent reviewers using a predefined data collection form. FINDINGS: In total, 56 RCTs were identified, including 4,039 individual postmenopausal women. There was substantial heterogeneity in quality across studies. Twenty-six (46%) RCTs showed poor quality and there was an indication of publication bias presence for some of the biomarkers. Results are reported in pooled mean difference (95% CI) of changes. Use of phytoestrogens was associated with a decrease in serum total cholesterol (-0.27 mmol/L [-0.41 to -0.13]), low-density lipoprotein (-0.25 mmol/L [-0.37 to -0.13]), triglycerides (-0.20 mmol/L [-0.28 to -0.11]), and apolipoprotein B (-0.13 g/L [-0.23 to -0.03]) and with an increase in serum apolipoprotein A-1 (0.04 g/L [0.02-0.07]. Also, phytoestrogen supplementation was associated with a decrease in serum intercellular adhesion molecule 1 (-18.86 ng/mL [-30.06 to -7.65]) and E-selectin (-2.32 ng/mL [-4.05 to -0.59]). There was no association observed between phytoestrogen supplementation and inflammatory markers, fibrinogen, homocysteine, or other endothelial function markers. In contrast, use of phytoestrogens was associated with an increase in CIMT (9.34 µm [95% CI, 0.39-18.29]). Effect estimates of phytoestrogen supplementation on oxidative stress could not be pooled. CONCLUSIONS AND RELEVANCE: Phytoestrogen supplementation seems to modestly improve the CVD risk profile of postmenopausal women by influencing blood lipids and parameters of endothelial function. In women with an increased risk of atherosclerosis, although modest, a harmful effect on CIMT progression may be present. Because of limited quality and the heterogeneous nature of the current evidence, additional rigorous studies are needed to explore the role of phytoestrogens in menopausal cardiovascular health. : Video Summary: http://links.lww.com/MENO/A593.

Video Summary: http://links.lww.com/MENO/A593.

Dietary fat, the gut microbiota, and metabolic health - A systematic review conducted within the MyNewGut project.

BACKGROUND AND AIMS: Studies indicate that dietary fat quantity and quality influence the gut microbiota composition which may as a consequence impact metabolic health. This systematic review aims to summarize the results of available studies in humans on dietary fat intake (quantity and quality), the intestinal microbiota composition and related cardiometabolic health outcomes. METHODS: We performed a systematic review (CRD42018088685) following PRISMA guidelines and searched for literature in Medline, EMBASE, and Cochrane databases. RESULTS: From 796 records, 765 records were excluded based on title or abstract. After screening of 31 full-text articles six randomized controlled trials (RCT) and nine cross-sectional observational studies were included. Our results of interventional trials do not suggest strong effects of different amounts and types of dietary fat on the intestinal microbiota composition or on metabolic health outcomes while observational studies indicate associations with the microbiota and health outcomes. High intake of fat and saturated fatty acids (SFA) may negatively affect microbiota richness and diversity and diets high in monounsaturated fatty acids (MUFA) may decrease total bacterial numbers whereas dietary polyunsaturated fatty acids (PUFA) had no effect on richness and diversity. CONCLUSIONS: High fat and high SFA diets can exert unfavorable effects on the gut microbiota and are associated with an unhealthy metabolic state. Also high MUFA diets may negatively affect gut microbiota whereas PUFA do not seem to negatively affect the gut microbiota or metabolic health outcomes. However, data are not consistent and most RCT and observational studies showed risks of bias.