A Japanese study published in the British Medical Journal found that people eating higher amounts of fermented soy products (like miso and natto) reduce their mortality risk. Participants with the highest intakes of fermented soy had a 10% lower risk, compared with those who had the lowest intakes. For participants who ate a lot of soy products that were not fermented, no significant association was found between intake of soy products and mortality rate.
Read more (British Medical Journal)