Natural health products in the prevention and treatment of osteoporosis: systematic review of randomized controlled trials.

BACKGROUND: Consumers are increasingly looking to natural health products to manage specific diseases such as osteoporosis. As a result, healthcare providers need evidence-based information on which to base recommendations regarding use and efficacy.

OBJECTIVE: To identify natural health products (NHPs, ie, dietary supplements) advocated for the prevention and treatment of osteoporosis and systematically review the evidence from randomized controlled trials for the effect of NHPs on bone mineral density (BMD)/fracture rate in women.

METHODS: MEDLINE, Natural Medicines Comprehensive Database, and the Internet were initially searched to identify NHPs advocated for prevention and treatment of osteoporosis. For NHPs having evidence to support their claim, the aforementioned sources, along with International Pharmaceutical Abstracts, the Cochrane Library, the International Bibliographic Information on Dietary Supplements, the Cumulative Index to Nursing & Allied Health, and HerbMed, were searched to locate randomized controlled trials published in English between 1966 and October 2004. Bibliographies of identified articles were also searched. Randomized controlled trials were selected if they evaluated the use of a single NHP in women, using BMD/fracture rate as the outcome measure. NHPs were excluded from further evaluation if a review had already been published. Data were extracted using predetermined criteria and studies appraised using the Jadad scale. Forty-five NHPs were identified that the authors claimed to be beneficial in prevention and treatment of osteoporosis, with 15 having evidence to support their claim. Calcium; copper; evening primrose oil; fish oils; fluoride; magnesium; manganese; strontium; vitamin D; and black, green, and oolong tea did not meet study criteria.

RESULTS: Results from randomized controlled trials evaluating dehydroepiandrosterone (DHEA), phytoestrogens, and vitamin K2 (menaquinone or menatetrenone) were promising; however, study limitations suggest the need for confirmatory evidence.

CONCLUSIONS: Although no definitive conclusions can be drawn, the relative safety of phytoestrogens, DHEA, and vitamin K2 at the studied doses, as well as preliminary positive results from randomized controlled trials, provides some initial support for the use of these NHPs in the prevention and treatment of osteoporosis in women.