Tokyo: Higher intake of fermented soy products, such as miso and natto, is associated with a lower risk of mortality, claims a study conducted in Japan. The findings, published in the British Medical Journal, should be interpreted with caution as they may have been affected by unmeasured factors, the researchers said.
In Asian countries, especially Japan, several types of soy products are widely consumed, such as natto -- soybeans fermented with Bacillus subtilis bacteria, miso or soybeans fermented with Aspergillus oryzae bacteria, and tofu or soybean curd.
However, it is still unclear whether different soy products, especially fermented soy products, are associated with specific health effects, according to the researchers, including those from Osaka University Graduate School of Medicine in Japan.
They analysed the association between several types of soy products and death from any cause, and from cancer, total cardiovascular disease, respiratory disease, and injury. The team based its 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 centre areas.
The researchers found that a higher intake of fermented soy (natto and miso) was associated with a significantly lower (10 per cent) risk of all cause mortality. However, total soy product intake was not associated with all cause mortality, they said.