Saw Palmetto Berry in the Treatment of Benign Prostatic Hyperplasia

Abstract

Phytotherapeutic agents are widely used for treating the symptoms of benign prostatic hyperplasia (BPH). Saw palmetto berry (SPB) is the most widely studied of these agents. It's mechanism of action is poorly understood. It does not have 5-alpha-reductase activity. The active ingredient in this extract is also unknown.

There is much controversy concerning the efficacy of SPB. The double-blind trials, although usually favorable, do not show usual placebo response as seen in other BPH studies. Because of the variability of the natural history of BPH, the uncontrolled studies of these agents contribute little to determine efficacy. Further well-design placebo-controlled trials are necessary to establish the safety and efficacy of phytotherapy in the treatment of BPH.

Phytotherapeutic agents have enjoyed widespread use, especially in Europe, for the treatment of BPH. With the recent proliferation of nutrition and vitamin stores in the United States, use of these agents has greatly increased.⁽²⁾ Although SPB extract is the most extensively studied of the phytotherapeutic agents used for BPH, no well-defined mechanism of action has been proposed. Evidence for an antiandrogenic or antiestrogenic effect is conflicting, and there are no clinical data suggesting an effect on 5-alpha-reductase activity. Furthermore, clinical trials with SPB have largely been uncontrolled and are thus of limited value in ascertaining the true clinical impact of this agent. Double-blind, controlled studies with SPB also have limitations in that most were of very short duration (none longer than 3 months) and did not provide entry or exclusion criteria. In addition, standardized symptom scores were not utilized. Only two of seven studies showed an appropriate placebo response, and the results and conclusions of both of these studies were contradictory.^(22,27)

The best and most convincing study of the efficacy of phytotherapeutic agents (using Harzol, a combination of beta-sitosterols) was recently published in the Lancet.³ This study was rigorous and matched in design and format with pharmaceutical industry trials. A mild but appropriate placebo response was detected, which further validates the study. However, a prior placebocontrolled study showed no efficacy of betasitosterol-beta-D-glucoside.⁽³⁶⁾ This dichotomy of results possibly reflects the different composition of the agents tested. This is a major confounding factor in this field of study, especially because the active ingredients are unknown. Standardization of the compounds is needed to compare and assess accurately the effect of the different extracts.⁽³⁷⁾