When oxygen is taken into the body through breathing, a part of it is invariably converted to reactive oxygen or free radicals. While free radicals positively affect cellular signaling and immune response, they also continuously damage the body by contributing to aging, cancer, and many other illnesses. Living beings have no way of escaping this. Therefore, a regular intake of antioxidants is necessary to neutralize free radicals and maintain the body’s balance. Regardless of whether one is in their teens or 70s, it is equally important.

Antioxidants can be ingested in one’s daily diet. Plant-based foods, in particular, are suitable for this. Vegetables with vibrant colors tend to have a more potent antioxidant effect, and carotenoid-rich vegetables high in beta-carotene like tomatoes and carrots, polyphenols found in the outer skins of vegetables, and catechins found in teas. Japanese fermented foods are made from rice and soybeans, rich in antioxidants as raw materials, and become even more vital during the fermentation process. 

Among such fermented foods, miso has a significant number of antioxidants.
The proteins in soybeans, when broken down, produce antioxidant peptides; the soybeans darken during fermentation and form melanoidins, and the odorants present in the yeast give the smell an antioxidant effect. While soy sauce has a similarly strong antioxidant effect, it can only have limited usage because of its salt concentration. Therefore, these foods can be used to full effect by drinking miso soup, adding soy sauce to fish, and eating vegetables in the usual way of Japanese meals. The bacteria in fermented foods can draw out nutritional value, and thus even a small amount added to a dish is highly effective.

Because antioxidants do not accumulate in the body, it is necessary to eat them every day. For that reason, the food being delicious is an essential factor. When people encounter something delicious, it sets off a pleasurable reaction in the brain that makes them feel better. Through the desire to eat good food day after day, the body can naturally improve health. In that sense, Japanese people who like the smell of fermented foods such as miso and soy sauce have an advantage. Thus, the good, fermented foods passed down in Japanese culture for a long time have led us happily to good health.