Herbs, vitamins and minerals in the treatment of premenstrual syndrome: a systematic review.

BACKGROUND As many women experiencing symptoms of premenstrual syndrome (PMS) seek relief from natural products (NP), health care providers should have quality information available to aid women in making evidence-based decisions regarding use of these products. OBJECTIVE To identify herbs, vitamins and minerals advocated for the treatment of PMS and/or PMDD and to systematically review evidence from randomized controlled trials (RCTs) to determine their efficacy in reducing severity of PMS/PMDD symptoms. METHODS Searches were conducted from inception to April 2008 in Clinical Evidence, The Cochrane Library, Embase, IBID, IPA, Mayoclinic, Medscape, MEDLINE Plus, Natural Medicines Comprehensive Database and the Internet to identify RCTs of herbs, vitamins or minerals advocated for PMS. Bibliographies of articles were also examined. Included studies were published in English or French. Studies were excluded if patient satisfaction was the sole outcome measure or if the comparator was not placebo or recognized therapy. RESULTS Sixty-two herbs, vitamins and minerals were identified for which claims of benefit for PMS were made, with RCT evidence found for only 10. Heterogeneity of length of trials, specific products and doses, and outcome measures precluded meta-analysis for any NP. Data supports the use of calcium for PMS, and suggests that chasteberry and vitamin B6 may be effective. Preliminary data shows some benefit with ginkgo, magnesium pyrrolidone, saffron, St. John's Wort, soy and vitamin E. No evidence of benefit with evening primrose oil or magnesium oxide was found. CONCLUSION Only calcium had good quality evidence to support its use in PMS. Further research is needed, using RCTs of adequate length, sufficient sample size, well-characterized products and measuring the effect on severity of individual PMS symptoms.