Based in Toronto and New York City

, Nancy Matsumoto is a writer and editor who covers sustainable agriculture, food, sake, arts and culture.

Archival posts from my former blog, Walking and Talking

Fermentation, Miso, and the Health Benefits of Soy

In the past two weeks, I attended two lectures that vastly increased my knowledge of two powerhouse fermented ingredients in Japanese cooking. One was a lecture on shiokoji, the miracle flavor enhancer and umami conductor that has for some time been all the rage in Japan. The other was a nutritional talk on the miracles of miso, the fermented soybean paste at the heart of miso soup and countless other flavorful Japanese dishes.

Nutrition researcher Lawrence H. Kushi, ScD, delivered a scientifically detailed and convincing ode to miso at a recent Japan Society lecture. The room was packed. Who knew there were so many miso lovers in this city?  Miso paste is pretty simple stuff. It's made of three ingredients: some type of grain, usually soybeans in Japan, koji (mold-innoculated rice) and water. 

Dr. Kushi's main points were nutritional. He  pointed out that Japan is third in worldwide average life expectancy (compared to the United States' sickly 51st place), despite Japan's famously high sodium intake. Dr. Kushi showed slides of numerous epidimiological studies. One of the earliest studies on miso and chronic diseases followed 250,000 people in Japan and showed a clear link between daily consumption of miso soup an a lower incident of stomach cancer. Miso has also been associated with lower rates of breast cancer. The doctor noted that "what you eat early in life makes a difference," so a high intake of soy products during childhood can exert a protective longterm effect. And even though miso is high in sodium, studies indicated that it is "a safer salt vehicle than salt," Dr. Kushi added.

There is a controversial side of miso, as one audience member pointed out. Soy contains isoflavones (a naturally occurring chemical compound) that are are similar to the hormone estrogen. The worry is that for women undergoing treatment for breast cancer, soy products may negate the effect of estrogen-blocking breast cancer drugs. Both Dr. Kushi and the American Cancer Society (see their "Expert Voices blog post on the topic) point out the shortcoming of studies that raised these fears, and stress the much more abundant evidence on the protective effects of soy.

Kushi, by the way, comes from a long line of educators; his father was Michio Kushi, the famous proponent of macrobiotics. One last interesting point, also raised by an audience member, is that studies have shown that gut bacteria of people in different cultures differs significantly. Apparently there is some evidence, for example, that Japanese people can extract more nutrients from seaweed-based foods than non-Japanese. Dr. Kushi noted that intestinal microbiata (the microbes that live in our intestines) are of great interest to the NIH, but that more study is needed. He also pointed out that when people move to another culture "they take on the disease characteristics of the place they live as they take on different eating habits and food choices."

If you're interested in how the typical Asian diet differs from a standard western diet, check out the Asian Diet Pyramid. Rice, noodles and whole grain products form the base, eaten daily, while meat is at the tip of the pyramid, a once-a-month rarity.

Since I didn't even get to the fascinating lecture by Japanese cooking expert Hiroko Shimbo on shiokoji, stay tuned for my upcoming post, which will be all about that!

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