A HIGHER intake of fermented soy products, such as miso and natto, is associated with a lower risk of death, according to a study in Japan.
However, the researchers stressed that the findings should be interpreted with caution as they may have been affected by unmeasured (confounding) factors.
In Asian countries including Japan and the Philippines, several types of soy products are widely consumed, such as natto, miso and tofu (soybean curd).
It is, however, still unclear whether different soy products, especially fermented soy products, are associated with specific health effects.
So a team of researchers in Japan set out to investigate the association between several types of soy products and death from any cause (“all cause mortality”) and from cancer, total cardiovascular disease (heart disease and cerebrovascular disease), respiratory disease, and injury.
They base their findings on 42,750 men and 50,165 women aged 45-74 years who were taking part in a study based in 11 of Japan’s public health center areas.
The researchers found that a higher intake of fermented soy (natto and miso) was associated with a significantly lower (10%) risk of all cause mortality, but total soy product intake was not associated with all cause mortality.
Men and women who ate natto also had a lower risk of cardiovascular mortality than those who did not eat natto, but there was no association between soy intake and cancer related mortality.
These results persisted even after further adjusting for intake of vegetables, which was higher among those consuming larger portions of natto.
The authors point out that fermented soy products are richer in fiber, potassium and bioactive components than their non-fermented counterparts, which may help to explain their associations.