ABSTRACT
The etiology of insulin resistance is poorly understood, but the general consensus that it is less common in individuals consuming diets rich in dietary fiber has led to growing speculation that a synergistic effect on both bioavailable estrogen and insulin sensitivity may be an important mechanism by which dietary fiber affords protection against breast cancer. Estrogens are central to the vast majority of mechanisms proposed to explain the epidemiology of breast cancer. Hyperinsulinemia and insulin resistance have been associated with increased levels of bioavailable estrogen and elevated breast cancer risk in the Netherlands. To date, only a few human studies have directly investigated the dietary intake of phytoestrogen-rich foods in relation to breast cancer risk. The report by W. V. Welshons et al. of the lignan enterolactone and the isoflavonoid metabolite equol stimulating growth of breast cancer cells in vitro is one example.
