Beneficial effects and side effects caused by isoflavones from food supplements and dermatocosmetic creams

Abstract

Introduction. Isoflavones are bioactive substances, also called phytoestrogens, because their chemical structure is similar to that of the human estradiol hormone. Significant amounts are found in soy and red clover in glycosidic form: genistin, daidzein and glycitin. The main users of isoflavone products are menopausal women seeking an alternative to hormone therapy. Currently, there are an enormous number of dietary supplements and cosmetic creams with isoflavones. Advertising and prospectuses assure consumers that products are natural, safe, although neither their benefit nor their safety has been sufficiently demonstrated. Aim of the study. Advanced bibliographic study on researches of the safety and risk-benefit ratio of isoflavones in food supplements and dermatocosmetic creams. Materials and methods. 116 abstracts and articles from systematic research in the Cochrane Electronic Library, MEDLINE databases, CAB Abstracts © CAB, and SciSearch © The Thomson Corporation. Results. Possible long-term carcinogenic effects and goitrogenic effects, by the thyroid inactivation of peroxidase by certain genistein concentrations (24% of the evaluated sources), have been identified. There are studies (21%) on adverse effects in fertility and reproductive tract toxicity in women. Experiments on mice after ovariectomy and implantation of breast cancer cells indicate stimulation of mammary tumor growth (5% of summaries). Several studies reveal an increased allergenic potential of isoflavones (9%). A large number of studies (27%) showed that genistein causes adverse effects on the female reproductive system, but also the involvement of isoflavones on central immune and central nervous systems (14%). However, a significant number of abstracts and articles can also be found, which also show beneficial effects in the improvement of vasomotor symptoms in the menopause. Conclusions. It has been found that data on the increased impact of isoflavones on menopausal problems of women are not enough and convincing, and long-term intake of high doses of isoflavone supplements for them is very risky.