A new study suggests that patients at risk of developing prostate cancer should drop the soy supplement as it isn’t that beneficial to them.
A group of researchers had an initial analysis result of 27.2 percent of prostate-specific antigen (PSA) recurrence rate even after taking soy supplements. The amount of PSA on a man’s blood indicates his risk of developing prostate cancer. The higher the amount of PSA is, the higher risk he has due to enlarge prostate.
Maarten C. Bosland, lead author of the study and professor at the University of Illinois at Chicago, and his colleagues conducted a randomized experiment to 177 men between July 1997 and May 2010 at seven medical centers.
The researchers selected patients who had undergone major prostatectomy for prostate cancer. They were given soy supplement within four months preceding the surgery which they had to take daily for two years. The researchers did PSA tests on them every two months during the first year then quarterly during the second year.
All of the participants thought that they were taking soy supplements but 90 of them were actually given calcium caseinate. When they compared the results of recurrence between those who took actual soy supplements, it only showed a difference of about two percent. Given this small amount of difference, it had proven that soy supplements will not really make any significant difference on the recurrence rate of prostate cancer.
Despite the negative result, the investigators clarified that the results pertain only to a particular patient population and further research is needed on a bigger population.
"The lack of protective activity of soy against prostate cancer recurrence observed in this study was limited to men at above-average risk of recurrence within the first 2 years after surgery and to the soy protein dose tested," Bosland wrote in the report.
The study was published on the July 10 issue of The JAMA Network.