Nattō (納豆, Nattō?) is a traditional Japanese food made from fermented soybeans, popular especially at breakfast. A rich source of protein, nattō and the soybean paste miso formed a vital source of nutrition in feudal Japan. For some, nattō can be an acquired taste due to its powerful smell, strong flavor, and sticky consistency. In Japan nattō is most popular in the eastern regions including Kanto and Tohoku.
The materials and tools needed to produce nattō (soybeans and straw) were commonly available in Japan since ancient times, so the discovery could have happened as early as in the Jomon period. It may also be possible that the product was discovered independently by numerous people at different times. The sources differ about the earliest origin of nattō. One source puts the first use of nattō in the Jomon period between 10,000 and 300 BC. According to other sources the product may also have originated in China during the Zhou Dynasty (1134 - 246 BC).
It prevents blood clots thus reducing the risks of strokes and heart disease, it is said that is prevents cancer too.