Page 84 - Fall2013

Soy Alert!

SINGING THE BLUES: SOY DOES ZIP FOR PROSTATE CANCER PATIENTS
By Kaayla T. Daniel, PhD

Does soy prevent prostate cancer or cut the In fact, this was a randomized, double-blind
risk of recurrence? With one out of six U.S. men trial conducted from July 1997 to May 2010 at
developing prostate cancer over their lifetimes, seven U.S. centers. A larger study would have
lots of people would like to think so. Although been highly unlikely to show the desired result
the soy industry loves to market its products ev- or would have found it at a level so small as to be
ery September during National Prostate Cancer insignificant. The soy drink and placebo groups
Awareness Month, this year they should not be were carefully randomized and did not differ
out wearing light blue wristbands and ribbons significantly in the distribution of risk factors,
and shilling soy milk in pretty blue containers. including the risk of recurrence. Adherence was
Rather they should be inside singing the blues. better than 90 percent, and there were no differ-
ences in adverse effects between the two groups.
DISAPPOINTING RESULTS Given that the “placebo” was calcium ca-
Why so? Bad news for the soy industry came seinate, soy did very poorly indeed. Casein is
July 10 when a Journal of the American Medi- a fractionated, poor-quality protein seriously
cal Association (JAMA) study showed soy won’t deficient in cysteine (a conditionally essential
prevent the recurrence of prostate cancer. The amino acid needed for immune support and
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study, from the University of Illinois, Chicago, detoxification) and rich in MSG and other dan-
proved “disappointing” even to its own research- gerous residues created during high temperature
ers, who had fully expected soy to help prevent processing. Though widely perceived as a neutral
prostate cancer recurrence. Lead researcher placebo protein, casein is routinely used in stud-
Maarten Bosland , DVSc, PhD, said he was disap- ies designed to make soy look good, particularly
pointed, but pleased at the clarity of the results. studies on soy, cholesterol and heart disease.
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“The results were statistically very solid and the Although the news headlines said the treat-
lack of treatment effect convincing. A lot of men ment had no effect, twenty-two of the soy patients
think that soy might be beneficial, but this study and twenty-three of the placebo patients had
shows that it’s not.” 2 prostate cancer recurrence. Interestingly, recur-
The researchers looked at one hundred rence for the soy patients came faster (average
seventy-seven men with an aggressive form of of thirty-one and one-half weeks), compared to
prostate cancer who had submitted to prosta- the placebo group (average of forty-four weeks).
tectomies and were at high risk for recurrence. While this difference was “statistically insig-
Supplement intervention was begun within four nificant,” it certainly is interesting. It raises the
months after surgery and continued for up to two question of whether the real reason this study was
years, with prostate-specific antigen (PSA) mea- stopped prematurely was not because soy proved
surements made at two month intervals during so ineffective but because risks were beginning
the first year and every three months thereafter. to emerge.
The study was Eighty seven men drank a soy beverage contain-
ing 20 grams of soy protein isolate and 90 men NOT EVERYONE CREATED EQUOL
stopped early received the placebo of calcium caseinate. The The JAMA article references a few studies
because the study was stopped early because the “treatment” that suggest soy can be helpful in prostate can-
“treatment” was obviously ineffective. cer, but overall the research on soy and prostate
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As expected, soy proponents have been cancer is inconsistent and contradictory. Some
was obviously whining that the study was badly designed, studies suggest soy increases prostate cancer
ineffective. poorly executed, and too small to be definitive. 3 risk, others suggest it decreases and still oth-
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