Effects of Phytoestrogens on Brain Chemistry, Structure, and Cognition

Abstract

Phytoestrogens are plant components that exert estrogenic effects on animal tissues. Soy isoflavones are the most extensively studied phytoestrogens. The effects of soy isoflavones on brain function, especially cognitive function, have become a very active research area in recent years. Studies in female rats and women indicate that soy isoflavones improve cognitive function in females. However, studies in male rats and young men resulted in conflicting results concerning isoflavones and cognition in the males. Soy isoflavones do not affect brain aromatase activity, but affect the sexually dimorphic region and 5α-reductase activity in some brain regions in male rats. Isoflavones may also affect brain function via estrogen-independent mechanisms. Much more work remains to be done to fully understand the effects of soy isoflavones and other phytoestrogens on brain chemistry, structure, and function.