TRAMP mice have been genetically modified so that they are more likely to develop prostate cancer than mice that have not been genetically tampered with. Grape Seed Extract [GSE] supplementation inhibits the incidence and development of prostate cancer in these lab mice, cancer researchers at the University of Colorado discovered.
The researchers gave the lab animals a daily oral dose of 200 mg Grape Seed Extract per kg bodyweight, 5 days a week from the age of 4 weeks on. [Scientists are just like the rest of us: they prefer not to work weekends.] The human equivalent of the dose they used would be 16.2 mg per kg per day. So if you weigh 80 kg you’d need 930 mg extract per day.
That seems like a modest dose, but don't forget that most Grape Seed Extract supplements only contain low doses: about 50 mg extract per capsule.
The extract used in the experiment was produced by Kikkoman of Japan, and consisted of 90 percent procyanidins and 7 percent free flavonols.
When the mice were 28 weeks old the researchers weighed their bladders, sperm vesicles and prostate [GUT], and discovered that the Grape Seed Extract supplementation had halved these weights, as you can see in the figure below.
Supplementation halved the percentage of mice that developed tumours, for both well-differentiated tumours [WUD] and undifferentiated tumours [UN].
Grape Seed Extract boosted the number of prostate cancer cells that committed suicide. The figure above shows that the number of prostate cells that committed suicide actually increased eightfold. On top of that, Grape Seed Extract also sabotaged the growth processes in the prostate cancer cells.
"Findings in the present study together with earlier findings suggest strong prostate cancer chemopreventive efficacy of Grape Seed Extract with scientific rationale and advocate for its potential clinical trial in human prostate cancer patients", the researchers conclude.
Cancer Res. 2007 Jun 15; 67(12): 5976-82.