Tofu, the soy product long touted as a health food, may be linked to increased risk of mental decline in older adults. Steeper age-related declines in brain structure and function in late life were found among study participants who had habitually consumed tofu more frequently in middle life. Men who ate two or more servings of tofu a week were more likely to show mental impairment and brain atrophy in old age than those who ate little or no tofu, according to the long-term study of 8,000 Japanese-American men living in Hawaii. In addition, similar results were seen in the 502 wives of the men who were looked at in the study. The men reported on their intake of a variety of foods in the mid-1960s and again in the early 1970s, and completed a variety of mental function tests about 20 years later, when they were aged 70 to early 90s. The researchers also did brain scans on almost 600 men and autopsies on 290 that had died. Tofu-eaters were more likely to have been born in Japan, but the investigators could find nothing about their early upbringing, such as nutrient intake or education that could explain the finding.

Journal of the American College of Nutrition April 2000;19:207-209, 242-255.