3 popular supplements fall short in preventing prostate cancer: study

by Deborah Braconnier report

(PhysOrg.com) -- For some time it has been believed that vitamin E, selenium and soy were natural ways to prevent prostate cancer. However, a new study published in the Journal of Clinical Oncology shows that these supplements do not provide any additional benefit when it comes to prostate cancer prevention.

Dr. Neil Fleshner, head of the urology department at the University Health Network in Toronto led the study on 303 men. All the men chosen for the study were at high risk for prostate cancer as they already showed pre-cancerous cells.

The researchers randomly chose men to receive the supplements while the others received a . These men were required to take these supplements every day for three years. The supplements contained a combination of 40g of soy, 800U of , and 0.2 milligrams .

After three years, the results of both groups came back the same. Within each group, 26 of every 100 developed prostate cancer. These results are similar to a study that was done in 2008 on vitamin E and selenium, where no benefit was found.

Researchers had hoped that the addition of soy in this study would show promise. In countries like China and Japan, where soy is eaten in large amounts, the rates of prostate cancer are much lower than those in the United States and Canada. Fleshner says that this does not rule out the benefits of a soy based diet for decades, but that three years of soy was not enough to show a change.

With 156 out of 10,000 men developing each year, Fleshner believes that this study provides enough proof that continued research into the benefits of these supplements should be abandoned and research funds turned to other possible ideas.

More information: Progression From High-Grade Prostatic Intraepithelial Neoplasia to Cancer: A Randomized Trial of Combination Vitamin-E, Soy, and Selenium, Journal of Clinical Oncology Published online before print May 2, 2011, doi:10.1200/JCO.2010.32.0994

Purpose High-grade prostatic intraepithelial neoplasia (HGPIN) is a putative precursor of invasive prostate cancer (PCa). Preclinical evidence suggests vitamin E, selenium, and soy protein may prevent progression of HGPIN to PCa. This hypothesis was tested in a randomized phase III double-blind study of daily soy (40 g), vitamin E (800 U), and selenium (200 μg) versus placebo.
Patients and Methods Three hundred three men in 12 Canadian centers were analyzed. The main eligibility criterion was confirmed HGPIN in at least one of two biopsies within 18 months of random assignment. Treatment was administered daily for 3 years. Follow-up prostate biopsies occurred at 6, 12, 24, and 36 months postrandomization. The primary end point was time to development of invasive PCa. Kaplan-Meier plots and log-rank tests were used to compare two treatment groups for this end point.
Results For all patients, the median age was 62.8 years. The median baseline prostate-specific antigen (PSA; n = 302) was 5.41 ug/L; total testosterone (n = 291) was 13.4 nmol/L. Invasive PCa developed among 26.4% of patients. The hazard ratio for the nutritional supplement to prevent PCa was 1.03 (95% CI, 0.67 to 1.60; P = .88). Gleason score distribution was similar in both groups with 83.5% of cancers graded Gleason sum of 6. Baseline age, weight, PSA, and testosterone did not predict for development of PCa. The supplement was well tolerated with flatulence reported more frequently (27% v 17%) among men receiving micronutrients.
Conclusion This trial does not support the hypothesis that combination vitamin E, selenium, and soy prevents progression from HGPIN to PCa.

Related Stories

Soy found protective against localized prostate cancer

date Mar 15, 2007

The largest study examining the relationship between the traditional soy-rich Japanese diet and development of prostate cancer in Japanese men has come to a seemingly contradictory conclusion: intake of isoflavone chemicals, ...

Some vitamin supplements don't protect against lung cancer

date May 21, 2007

A study of more than 75,000 adults found that taking supplemental multivitamins, vitamin C and E and folate do not decrease the risk of lung cancer. The findings are being reported at the American Thoracic Society 2007 International ...

Soy may stop prostate cancer spread

date Nov 08, 2010

Northwestern Medicine researchers at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University have found that a new, nontoxic drug made from a chemical in soy could prevent the movement of cancer cells from ...

Recommended for you

Teens with breast lumps may be able to avoid invasive biopsy

date 31 minutes ago

If a lump is found in the breast of an adolescent girl, she often will undergo an excisional biopsy. However, breast cancer is rare in adolescents, and the vast majority of teenage breast lumps turn out to be benign masses ...

To stop cancer: Block its messages

date 4 hours ago

The average living cell needs communication skills: It must transmit a constant stream of messages quickly and efficiently from its outer walls to the inner nucleus, where most of the day-to-day decisions ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

May 06, 2011
the title of this unbiased paper should be "vitamin E, selenium and soy fall short in preventing prostate cancer". Otherwise you people should use general labels to report all research. For example, "pharmaceuticals failed to stop infections" because three pharmaceuticals drugs failed containing a disease....
May 10, 2011

I think vitamin D would have a better chance. It has been shown to prevent several other types of cancer, in various studies, performed at University of California Medical Centers, as well as those of other universities.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.