Decreased serum total cholesterol concentration is associated with high intake of soy products in Japanese men and women.

The relationship between soy product intake and serum total cholesterol concentration was examined in 1242 men and 3596 women who participated in an annual health check-up program in Takayama City, Japan, provided by the municipality in 1992. The intake of soy products and various foods and nutrients was assessed by a semiquantitative food-frequency questionnaire. Blood samples were collected from fasting subjects to measure the serum total cholesterol concentration. A significant trend (P for trend = 0. 0001) was observed for decreasing total cholesterol concentration with an increasing intake of soy products in men after controlling for age, smoking status and intake of total energy, total protein and total fat. This negative trend (P for trend = 0.0001) was also noted in women after controlling for age, menopausal status, body mass index and intake of total energy and vitamin C. An additional adjustment for physical activity, coffee and tea consumption, and intake of cholesterol, carbohydrates, fiber and vitamin E did not change the results. These data suggest a role for soy products in human cholesterol homeostasis.