| Title | Side effects of phytoestrogens: a meta-analysis of randomized trials. | | Author(s) | Tempfer CB, Froese G, Heinze G, Bentz EK, Hefler LA, Huber JC | | Institution | Department of Obstetrics and Gynecology, Medical University Vienna, Vienna, Austria. clemens.tempfer@meduniwien.ac.at | | Source | Am J Med 2009 Oct; 122(10):939-46.e9. | | MeSH | Breast Neoplasms
Dietary Supplements
Dose-Response Relationship, Drug
Drug Administration Schedule
Drug Toxicity
Endometrial Hyperplasia
Endometrial Neoplasms
Estrogen Replacement Therapy
Female
Follow-Up Studies
Gastrointestinal Diseases
Humans
Incidence
Phytoestrogens
Plant Extracts
Postmenopause
Randomized Controlled Trials as Topic
Risk Assessment
Uterine Hemorrhage
| | Abstract | 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. | | Language | eng | | Pub Type(s) | Comparative Study
Journal Article
Meta-Analysis
Review
| | PubMed ID | 19786161 |
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