β-sitosterol for the treatment of benign prostatic hyperplasia: A systematic review

Objectives. To conduct a systematic review of the evidence for the efficacy of β-sitosterol in men with symptomatic benign prostatic hyperplasia (BPH). Methods. Studies were identified through Medline(TM) (1966-98). EMBASE(TM), Phytodok, the Cochrane Library, bibliographies of identified trials and review articles, and contact with study authors and pharmaceutical companies. Randomized trials were included if: men had symptomatic BPH; plant extract preparations contained β-sitosterols; a control group received placebo or a pharmacological therapy; and treatment duration was ≥ 30 days. Study characteristics, demographic information enrolment criteria and outcomes were extracted. Results. Four trials comprising a total of 519 men met the inclusion criteria. All were double-blind and lasted 4-26 weeks. Three studies used nonglucosidic β-sitosterols and one used a preparation that contained only β-sitosterol-β-D-glucoside. Compared with placebo, β-sitosterol improved urinary symptom scores and flow measures. For the two studies reporting the International Prostate Symptom Score (IPSS), the weighted mean difference (WMD) against placebo was -4.9 IPSS points (95% confidence interval, CI, -6.3 to -3.5). The WMD for peak urinary flow rate was 3.91 mL/s (95% CI 0.91 to 6.90, four studies) and for residual volume the WMD was -28.62 mL (95% CI -41.42 to -15.83, four studies). β-sitosterol did not reduce prostate size. The trial using pure β-sitosterol-β-D-glucoside (WA184) showed no improvement in urinary flow measures. Withdrawal rates for men assigned to β-sitosterol and placebo were 7.8% and 8.0% (not significant), respectively. Conclusion. β-sitosterol improved urological symptoms and flow measures. However, the existing studies are limited by short treatment duration and lack of standardized β-sitosterol preparations. Their long-term effectiveness, safety and ability to prevent the complications of BPH are unknown.