By TAP Integrative

In about a third of the people living in Western countries and more than half of Asian people, soy intake causes the bacteria in the large intestine to produce a substance called equol. Equol is thought to have heart-protective effects, and is a metabolite of the soy isoflavone daidzein.

The people who produce equol are at a cardiovascular advantage, with better measures of blood pressure, arterial stiffness, endothelial function, lipids, inflammatory biomarkers, and nitric oxide than the rest of the population.

Unfortunately we can’t change whether or not we’re born as equol producers, but researchers have been investigating whether it’s possible to get some of the same health protective effects by taking a commercially bacterium-produced equol supplement.

In a randomized, double-blind, placebo-controlled crossover study published in March 2016 in the American Journal of Clinical Nutrition, researchers recruited 28 healthy men with 10– 20% 10-y absolute risk of CVD. No participants were taking any medications or flavonoid-containing supplements for at least a month prior to study enrollment. Half of the participants were equol producers and half were not. The study had two phases. The first phase compared the vascular response to a single 80mg dose of isoflavones among all participants compared to placebo. The second phase compared a commercially produced 40mg equol supplement given to non-equol producers to placebo in equol producers in order to determine if this produced a vascular response in the non–equol producers.

The findings confirmed the benefits of being an equol producer. After the single 80mg isoflavone dose, the men who produced equol experienced a significant improvement in a measure of arterial stiffness. The improvement would equate to an 11-12% reduction in cardiovascular disease risk for men at moderate risk of cardiovascular disease. Unfortunately, while the non–equol producers did experience increased serum equol after taking the commercially produced equol supplement, their vascular function did not change. This suggests that, in the acute setting, only equol producers will gain vascular benefits of elevated equol.

The study was small and only examined the effects of a single dose of equol, but it does point to the critical role of the equol producing phenotype in obtaining cardiovascular health benefits from soy.


Hazim S, Curtis PJ, Schär MY, et al. Acute benefits of the microbial-derived isoflavone metabolite equol on arterial stiffness in men prospectively recruited according to equol producer phenotype: a double-blind randomized controlled trial. Am J Clin Nutr. 2016;103(3):694-702.


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*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.