High-fiber diet reduces serum estrogen concentrations in premenopausal women.

The effect of dietary fiber on serum estrogen concentrations was studied in 62 premenopausal women. Their estimated daily dietary fiber intake was increased from an average of approximately 15 g to 30 g/d by supplementation with wheat, oat, or corn bran. This was done without any significant decrease in dietary fat consumption. After 2 mo on the high-fiber diets, the wheat-bran-supplemented group showed significant reductions in serum estrone (P less than 0.002) and estradiol (P less than 0.02) but no change in serum progesterone or sex-hormone-binding globulin concentrations. The serum estrogens were unaffected by dietary-fiber supplementation with oat or corn brans.