[Dietary isolated isoflavone supplements for peri- and postmenopausal women: risks and questionable benefits]

Isolated isoflavones are frequently offered as dietary supplements for the alleviation of peri- and postmenopausal complaints. These mainly soy-based secondary plant compounds are marketed with the claim of having numerous beneficial effects such as protection against breast cancer, osteoporosis, and cardiovascular diseases. Currently, there is no conclusive evidence for most of these health impacts. In addition, there is a controversial ongoing discussion about the safety of these products. After a long-term intake of high isoflavone doses, adverse effects on the breast tissue, the endometrium, and the thyroid, the last one especially under iodine-deficient conditions, cannot be excluded. Owing to their estrogenic effects, isoflavones may promote the growth of estrogen-sensitive malignant cells. The risk assessment of isoflavones is especially focused on peri- and postmenopausal women because they are the target group for dietary supplements based on isolated isoflavones and have, anyway, a higher risk for breast cancer. Since long-term treatment with isolated isoflavones, especially at high doses, is considered critical, we recommend that patients consume isoflavone-based supplements only after advice and under medical supervision.