More Bad News for Vitamin Supplements: Vitamin E and Selenium Increase Prostate Cancer Risk

By

Roy M. Arnold, MD

On the heels of a study showing no beneficial effect of multivitamin supplements on cancer, stroke or heart disease¹, a new study published in The Journal of the National Cancer Institute² showed  not only no benefit in preventing prostate cancer, but also an increase in prostate cancer in certain men. The study, known as the SELECT trial looked at 35,000 men who were randomized to receive either Vitamin E 400IU daily, Selenium 200micrograms daily, both or neither. The Study which began in 2001 was initially scheduled to run 12 years but was stopped in 2008, because no benefit was apparent. The participants were followed thereafter and analysis actually showed that both Vitamin E and Selenium actually increased risk of prostate cancer. In the case of Vitamin E, the risk increased 17% over controls. The increase seen with Selenium was somewhat smaller.

Vitamin E is an essential nutrient found in foods such as vegetables, vegetable oils, nuts, and egg yolks. Selenium is a trace element found in rice, wheat, and Brazil nuts, and in seafood and meat. Both substances are considered to be antioxidants.

Furthermore, the men who already had high levels of Selenium at the beginning of the trial and who received Selenium experienced a 91% increase in high grade prostate cancers. Those with low Selenium levels who received only Vitamin E also experienced a statistically significant increase in prostate cancer.

Selenium occurs naturally in the environment and can be concentrated from agricultural runoff by aquatic species. In certain regions of the US, consumption of wild game meat has led to toxic levels in humans.

The authors of the NCI Journal study state, “that effects of supplementation are dependent upon the nutrient status of the target population, such that supplementation of populations with adequate nutrient status, leading to supraphysiological exposure, has either no effect or increases cancer risk…” The authors also state, “These new results are consistent with the medical literature on supplements and cancer. The message is that nothing good is gained in healthy people.”

Lest one think that I am totally against supplements and vitamins, bear in mind that the Centers for Disease Control and Prevention recommend supplemental folic acid for all women of childbearing age because of its usefulness in preventing certain types of birth defects. The CDC’s 2012 report on Nutritional status found that certain populations, most notably African-Americans, Hispanics and the elderly have a high prevalence of Vitamin D deficiency.

Dr. Edgar Miller, a professor of medicine and epidemiology at Johns Hopkins Bloomberg School of Public Health in Baltimore and an author of an accompanying editorial to the study published in December has been quoted as saying, “The ‘stop wasting your money’ means that perhaps you’re spending money on things that won’t protect you long term. What will protect you is if you spend the money on fruits, vegetables, nuts, beans, low fat dairy, things like that… and exercising would probably be a better use of the money.”

As with anything you read in print, it is important to discuss this matter with your primary healthcare provider before changing anything.

¹ Annals of Internal Medicine, December 16, 2013.

² J Natl Cancer Inst. Published online February 22, 2014. http://jnci.oxfordjournals.org/content/early/2014/02/21/jnci.dju005.extract