Men who take high doses of Grape Seed Extract over a longer period are 62 percent less likely to develop prostate cancer than men who don’t take the supplement. Researchers at the University of Washington discovered this when they tracked 35,000 men aged between 50 and 76 over a period of six years.
The study, the results of which were published in Nutrition and Cancer, is part of the Vital project, an epidemiological research project to study the positive effects of long-term supplement use. This particular part of the project focused on prostate cancer.
The researchers looked at the use of supplements that would be expected to reduce the chance of prostate cancer, such as Grape Seed Extract, chondroitin, Q10, fish oil, garlic, Ginkgo biloba, ginseng, glucosamine and of course saw palmetto.
Of all these supplements, Grape Seed Extract was the only one that reduced the likelihood of prostate cancer by a statistically significant amount. Users had 41 percent less chance of developing prostate cancer than non-users. Among the long-term users who took higher doses the effect was even stronger.
Numbers 2 and 3 in the Anti-Prostate Cancer Top Ten are fish oil and ginseng, but neither performed well in this study.
Grape Seed Extract contains phenols: flavones, phenolic acids and resveratrol. In experiments with prostate cancer cells, Grape Seed Extract and its components inhibit the transcription factor nuclear factor kappa-B, the inflammatory protein interleukine-6 and the biosynthesis of inflammatory factors produced by cyclooxygenase enzymes, thereby blocking the growth of prostate cancer cells.
This is the first study directed specifically at supplements’ ability to protect against prostate cancer. Because not much is known, the researchers are cautious. “Any public health recommendation for grapeseed would require replication of our findings in humans as well as further clarification of mechanisms of action.”
Specialty supplements and prostate cancer risk in the VITamins and Lifestyle (VITAL) cohort.
Although there is evidence from studies of prostate cancer cell lines and rodent models that several supplements may have antiinflammatory, antioxidant, or other anticancer properties, few epidemiologic studies have examined the association between nonvitamin, nonmineral, “specialty” supplement use and prostate cancer risk. Participants, 50-76 yr, were 35,239 male members of the VITamins and Lifestyle (VITAL) cohort who were residents of western Washington state, and who completed an extensive baseline questionnaire in 2000-2002. Participants responded about their frequency (days/wk) and duration (yr) of specialty supplement uses. 1,602 incident invasive prostate cancers were obtained from the Surveillance, Epidemiology, and End Results registry. Multivariate-adjusted hazards ratios (HR) and 95% confidence intervals (95% CI) were estimated by Cox proportional hazards models. Any use of grapeseed supplements was associated with a 41% (HR 0.59, 95% CI: 0.40-0.86) reduced risk of total prostate cancer. There were no associations for use of chondroitin, coenzyme Q10, fish oil, garlic, ginkgo biloba, ginseng, glucosamine, or saw palmetto. Grapeseed may be a potential chemopreventive agent; however, as current evidence is limited, it should not yet be promoted for prevention of prostate cancer.
PMID: 21598177 [PubMed – indexed for MEDLINE] PMCID: PMC3100666