Tofu And Bad Brains Tofu may not be brain food. The soy product may be linked to mental decline in older people, according to a report in the Journal of the American College of Nutrition. Researchers from the Hawaii Center for Health Resources did a long-term study on 8,000 Japanese-American men living in Hawaii. The men were asked to report on their intake of a variety of foods in the mid-1960s and again in the early 1970s. About 20 years later the men, now in their 70s to early 90s, were given mental function tests. Six hundred of them also underwent brain scans, and autopsies were performed on 290 men who had died. The researchers found that the men who ate two or more servings of tofu a week were more likely to experience mental impairment and brain atrophy in old age than the men who ate little or no tofu, Reuters reports. The researchers also saw similar results in 502 of the wives of men who participated in the study. However, the study is considered preliminary and the researchers could not definitively say whether soy consumption caused mental decline or if the decline was related to some other lifestyle factor. They found that frequent tofu eaters were more likely to have been born in Japan but could find no other similarities in their upbringing, Reuters says. It is not clear why tofu might contribute to mental decline, but the researchers say it is possible that the phytoestrogens that are found in soy might affect the aging brain.