Effect of S-equol and Soy Isoflavones on Heart and Brain

Abstract

Background:Observational studies in Asia show that dietary intake of soy isoflavones had a significant inverse association with coronary heart disease (CHD). A recent randomized controlled trial (RCT) of soy isoflavones on atherosclerosis in the US, however, failed to show their benefit. The discrepancy may be due to the much lower prevalence of S-equol producers in Westerners: Only 20-30% of Westerners produce S-equol in contrast to 50-70% in Asians. S-equol is a metabolite of dietary soy isoflavone daidzein by gut microbiome and possesses the most antiatherogenic properties among all isoflavones. Several short-duration RCTs documented that soy isoflavones improves arterial stiffness. Accumulating evidence shows that both atherosclerosis and arterial stiffness are positively associated with cognitive decline/dementia. Therefore, potentially, soy isoflavones, especially S-equol, are protective against cognitive decline/dementia. </P><P> Methods/Results: This narrative review of clinical and epidemiological studies provides an overview of the health benefits of soy isoflavones and introduces S-equol. Second, we review recent evidence on the association of soy isoflavones and S-equol with CHD, atherosclerosis, and arterial stiffness as well as the association of atherosclerosis and arterial stiffness with cognitive decline/ dementia. Third, we highlight recent studies that report the association of soy isoflavones and S-equol with cognitive decline/dementia. Lastly, we discuss the future directions of clinical and epidemiological research on the relationship of S-equol and CHD and dementia.Conclusions:Evidence from observational studies and short-term RCTs suggests that S-equol is anti-atherogenic and improves arterial stiffness and may prevent CHD and cognitive impairment/ dementia. Well-designed long-term (≥ 2years) RCTs should be pursued.

Gut Microbiota and Its Metabolites in Atherosclerosis Development

“…Previous clinical trial has shown that equol may display a fundamental atheroprotective properties of isoflavones in Japanese men [73]. The evidence from another observational studies and short-term randomized controlled trials has suggested that equol is anti-atherogenic and improves arterial stiffness and may prevent coronary heart disease [58]. Therefore, equol, a metabolite of daidzein gut microbes, has a significant developmental prospect for cardiovascular health and disease prevention.…”

Gut Health-Promoting Benefits of a Dietary Supplement of Vitamins with Inulin and Acacia Fibers in Rats

“…Moreover, acacia fiber supplementation produced the appearance of the genus Asaccharobacter (which belongs to the Actinobacteria phylum) in female rats, a single species of which has been reported to be a powerful equol producer [ 40 ]. Therefore, older people receiving the acacia fiber-enriched supplement may benefit from equol’s health-promoting benefits, as has been reported, for example on osteoporosis, prostate cancer, and cardiovascular diseases [ 41 , 42 ].…”

Soy and Isoflavone Consumption and Multiple Health Outcomes: Umbrella Review of Systematic Reviews and Meta‐Analyses of Observational Studies and Randomized Trials in Humans

“…In addition, subgroup analysis according to locations showed a significant inverse relationship of soy intake in Asians but not in Westerners. These findings may be partly explained by the much higher intake of soy in Asians and much lower prevalence of S‐equol producers in Westerners: only 20–30% of Westerners produce S‐equol in contrast to 50–70% in Asians . S‐equol is a metabolite of dietary soy isoflavone daidzein by gut microbiome and possesses the most antiatherogenic properties among all isoflavones .…”