Am J Med. 2009 Oct;122(10):939-46.e9.
Side effects of phytoestrogens: a meta-analysis of randomized trials.
Tempfer CB, Froese G, Heinze G, Bentz EK, Hefler LA, Huber JC.
Department of Obstetrics and Gynecology, Medical University Vienna, Vienna, Austria. clemens.tempfer@meduniwien.ac.at
BACKGROUND: Phytoestrogens are widely used by postmenopausal women for the treatment of the climacteric syndrome. The risk of adverse effects of this treatment, however, is unknown. METHODS: Using a fixed-effects model, we performed a meta-analysis of side effects comparing phytoestrogen treatment with placebo or no treatment in randomized controlled trials. RESULTS: We identified 174 randomized controlled trials. Side effects were reported in 92/174 randomized controlled trials with 9629 participants. The overall incidence of side effects in the phytoestrogen and control groups was 2019/5502 (36.7%) and 1824/4806 (38.0%), respectively (P=.2; incidence rate ratio [IRR] 1.01; 95% confidence interval [CI], 0.95-1.08). Comparing various side effect categories, we found significantly higher rates of gastrointestinal side effects among phytoestrogen users (P=.003; IRR 1.28; 95% CI, 1.08-1.50). Gynecological (IRR 0.94; 95% CI, 0.74-1.20), musculoskeletal (IRR 1.20; 95% CI, 0.94-1.53), neurological (IRR 0.91; 95% CI, 0.70-1.19), and unspecific side effects (IRR 0.95; 95% CI, 0.88-1.03) were not significantly different between groups. Within side effect categories, we found no significantly higher rates of side effects in women using phytoestrogens. Specifically, the rates of hormone-related side effects such as endometrial hyperplasia, endometrial cancer, and breast cancer were not significantly different between groups. CONCLUSIONS: Based on the available evidence, phytoestrogen supplements have a safe side-effect profile with moderately elevated rates of gastrointestinal side effects. Rates of vaginal bleeding, endometrial hyperplasia, endometrial cancer, and breast cancer were not significantly increased among phytoestrogen users in the investigated studies.
Most Read
- The need for long-term thinking in medicine: Cinnamon as a case study
- Love, Fertility and Reproductive Health
- A brief and practical introduction to pulse and tongue assessment
- Plant allies for winter health
- Some sping tonic formulas for extraction
- Soy (and phytoestrogens) are safe and helpful in breast cancer
- Safety of phytoestrogens reviewed
- Use of Astragalus plants as a Herbs
- Lets go back to Long pepper season
- Infusions with Nourishing Herbs
- Aromatic plants – cultivating the scented garden within.
