Phytoestrogens: a review of recent findings.

Phytoestrogens have been investigated at the epidemiological, clinical and molecular levels to determine their potential health benefits. The two major groups of phytoestrogens, isoflavones and lignans, are abundant in soy products and flax respectively, but are also present in a variety of other foods. It is thought that these estrogen-like compounds may protect against chronic diseases, such as hormone-dependent cancers, cardiovascular disease and osteoporosis. Furthermore, phytoestrogens are used as a natural alternative to hormone replacement therapy and to reduce menopausal symptoms. Phytoestrogens have been shown to induce both estrogenic and anti-estrogenic effects but their biological relevance and potency have not been well characterized. In children, consumption of soy-based formulas and soy milk can lead to high levels of exposure to phytoestrogens with only limited data available concerning potential benefits or adverse effects. Phytoestrogens are considered good candidates for use in natural therapies and as chemopreventive agents in adults. Safe and efficacious levels have yet to be established.