DWM fermented soy intake (e.g., natto, miso) was associated significantly and inversely with all-cause death

Does Consuming Soy Enhance Longevity?

Paul S. Mueller, MD, MPH, FACP reviewing Katagiri R et al. BMJ 2020 Jan 29

Fermented soy intake is associated with lower risk for death.

Soy is widely viewed as a healthful food. However, whether intake of soy products (unfermented and fermented) is associated with longer life expectancy is unclear. In this prospective population-based cohort study that involved 93,000 men and women (age range, 45–74) in Japan, researchers examined associations between soy intake and death.

During 15 years of follow-up (in which 13,000 deaths occurred), total soy intake was not associated with all-cause death; however, fermented soy intake (e.g., natto, miso) was associated significantly and inversely with all-cause death in both men and women. In analyses adjusted for potentially confounding variables, all-cause death was 10% lower among people in the highest quintile of fermented soy intake than among those in the lowest quintile.

COMMENT

In this study, fermented soy intake, not total soy intake, was associated with lower risk for death. And considering that the researchers did not adjust for the known high salt content of fermented soy products, the salutary effects of fermented soy intake might even have been underestimated. The authors speculate that fermented soy products are better for health than unfermented soy products (such as tofu) because they are richer in potassium, fiber, and beneficial bioactive compounds.