Beta-sitosterol supplements seem to be most appropriate for younger men with minimal symptoms who wish to avoid clinical drug regimens for benign prostatic hyperplasia treatment, according to the findings of a recent literature review.
Herbal supplements containing plant sterols, vitamins, and minerals are widely used to enhance prostate health. Beta-sitosterol often forms the most abundant component of these supplements.
A study in the American Journal of Clinical and Experimental Urology reviewed the available evidence regarding the efficacy, safety, and mechanisms of action of beta-sitosterol for treating prostate cancer (PCa) and benign prostatic hyperplasia (BPH).
Promotes Apoptosis of Pca Cells
Initial research on beta-sitosterol focused on in vitro cultured PCa cells. Awad et al. found that beta-sitosterol reduced invasiveness, motility, and laminin–fibronectin binding in PC-3 cells and diminished tumor growth and metastases in mice. They concluded that beta-sitosterol may inhibit tumor growth by inducing apoptosis and cell cycle arrest through alterations in reactive oxygen species and prostaglandin production. Multiple other studies corroborated these findings in various PCa cell lines.
Other mechanisms highlighted were decreased anti-apoptotic proteins, increased pro-apoptotic proteins, inhibition of migration and proliferation of cancer cells, and altered membrane composition. Findings from recent in vivo studies are consistent with the previous conclusions that beta-sitosterol may induce PCa cell apoptosis. Beta-sitosterol may also exert anti-tumorigenic effects by interacting with specific proteins and influencing gene expression and immune responses. However, there is no definitive evidence regarding its therapeutic potential for PCa.
Reduces Prostatic Epithelial Proliferation
Dihydrotestosterone (DHT) binds to androgen receptors (ARs) on epithelial and stromal prostatic cells and regulates gene expression. Disruptions in this process contribute to prostate enlargement. Plant sterols, including beta-sitosterol, chemically resemble DHT and 5α-reductase inhibitors. In vitro studies revealed that saw palmetto extracts inhibited 5α-reductase, the enzyme that converts testosterone to its active DHT form.
Studies in rat models demonstrated beta-sitosterol’s ability to dramatically reduce prostatic hyperplasia, comparable to finasteride. Moreover, these phytosterols may decrease testosterone levels by competing with cholesterol for intestinal absorption. In one study, beta-sitosterol-enriched saw palmetto oil (VISPO) exhibited superior efficacy compared to conventional saw palmetto (SPO) and finasteride in reducing prostate weight, testosterone levels, inducing apoptosis, and reducing inflammation in rat models of testosterone-induced BPH. Beta-sitosterol’s effects are not well documented in the prostatic stromal tissues of rats.
Beta-Sitosterol-Containing Phytosterols Prove Efficacious in BPH Treatment
The first large clinical study, conducted in Germany in 1993, found beta-sitosterol efficacious in treating BPH, significantly improving symptoms and urinary flow parameters. Another study by Marks et al. tested a saw palmetto herbal blend and noted no change in prostate volume but observed epithelial contraction in the transition zone and increased atrophic glands, akin to finasteride’s effects.
Additionally, the PERMAL study, a large trial evaluating the efficacy of Permixon (extract of Serenoa repens) concluded that Permixon was slightly superior to tamsulosin in reducing lower urinary tract symptoms (LUTS) in severe BPH. Other studies found similar efficacy of Serenoa repens extract and tamsulosin in treating BPH but no added benefits with combined therapy.
On the contrary, the first large American study found no substantial difference between saw palmetto and placebo in improving symptoms or objective measures of BPH. However, a subsequent study indicated significantly reduced symptoms with VISPO versus placebo or SPO. The TRIUMPH study, a large European trial, found that phytosterols, although improving symptoms significantly, were less effective than alpha-blockers and 5α-reductase inhibitors.
A meta-analysis of various publications came to the conclusion that Serenoa repens extracts showed some efficacy in alleviating LUTS, at least after 1 year of use, and might be appropriate for patients who want to avoid alpha-blockers and do not require rapid symptom relief. No adverse events or toxicities have been documented with these supplements. Collectively, these data have led investigators to conclude that beta-sitosterol supplements might be most appropriate for younger men with minimal symptoms who do not want to take clinical drugs for BPH.
Source:
Macoska J. A. (2023). The use of beta-sitosterol for the treatment of prostate cancer and benign prostatic hyperplasia. American journal of clinical and experimental urology, 11(6), 467–480. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10749388/
