Postprandial changes in sex hormones after meals of different composition

The postprandial effects of different meals on serum testosterone, serum sex hormone-binding globulin (SHBG), and free androgen index were sequentially evaluated in 15 healthy men. The isocaloric meals contained different proteins and different quantities and type of fat as a mixed meal. Four test meals were given to subjects in random order: a lean meat meal, a tofu meal (both containing approximately 20% energy from fat), and meat meals with added animal fat or safflower oil (both 54% energy from fat). Blood samples were obtained at baseline and at 2, 3, and 6 hours after each meal. There was a significant decrease in testosterone and free androgen index after both tofu and lean meat meals. The 2-hour serum testosterone and the decremental area under the curve were significantly more negative after the lean meat meal than the meat meal with added animal fat. The testosterone area under the curve was least for the high animal fat meal indicating little change from baseline. As men are postprandial for a significant proportion of the day, the lower sex hormone values after a low animal fat meal may provide long-term benefits in reducing the risk of diseases, such as prostate cancer, which appear to be sex hormone-dependent.