Featured Research

from universities, journals, and other organizations

Selenium, vitamin E supplements can increase risk of prostate cancer in some men

Date:
February 21, 2014
Source:
Fred Hutchinson Cancer Research Center
Summary:
High-dose supplementation with both the trace element selenium and vitamin E increase the risk of high-grade prostate cancer. But importantly, this risk depends upon a man’s selenium status before taking the supplements. "Men using these supplements should stop, period. Neither selenium nor vitamin E supplementation confers any known benefits -- only risks," the lead author stated. "While there appear to be no risks from taking a standard multivitamin, the effects of high-dose single supplements are unpredictable, complex and often harmful. There are optimal levels, and these are often the levels obtained from a healthful diet, but either below or above the levels there are risks."

A multi-center study led by Fred Hutchinson Cancer Research Center has found that high-dose supplementation with both the trace element selenium and vitamin E increase the risk of high-grade prostate cancer. But importantly, this risk depends upon a man's selenium status before taking the supplements.

These findings, published in Journal of the National Cancer Institute, are based on data from the Selenium and Vitamin E Cancer Prevention Trial, or SELECT, a rigorously executed, randomized and placebo-controlled trial conducted by the SWOG cancer research cooperative group that involved more than 35,000 men. The study sought to determine whether taking high-dose vitamin E (400 IU/day) and/or selenium (200 mcg/day) supplements could protect men from prostate cancer.

The trial, which began in 2001 and was designed to last 12 years, stopped early, in 2008, because it found no protective effect from selenium and there was a suggestion that vitamin E increased risk. While use of the study supplements stopped, men were still followed and after an additional two years the men who took vitamin E had a statistically significant 17 percent increased risk of prostate cancer.

Selenium supplementation increased cancer in men with high selenium status at baseline

When the study started, there was some evidence that selenium supplementation would not benefit men who already had an adequate intake of the nutrient. For that reason, researchers measured the concentration of selenium in participants' toenails and planned to test whether selenium supplementation would benefit only the subset of men with low selenium status at baseline. Instead, they found that taking selenium supplements increased the risk of high-grade cancer by 91 percent among men with high selenium status at baseline. When selenium supplements were taken by men who had high selenium status to begin with, the levels of selenium became toxic.

Taking vitamin E increased cancer risk in men with low selenium status at baseline

The study also found that only a subgroup of men was at increased risk of prostate cancer from taking vitamin E. Among men with low selenium status at baseline, vitamin E supplementation increased their total risk of prostate cancer by 63 percent and increased the risk of high-grade cancer by 111 percent. This explained one of the original SELECT findings, which was that only men who received vitamin E plus a placebo pill, and not those who received both vitamin E and selenium, had an increased prostate cancer risk. Selenium, whether from dietary sources or supplements, protected men from the harmful effects of vitamin E.

"Many people think that dietary supplements are helpful or at the least innocuous. This is not true," said corresponding and first author Alan Kristal, Dr.P.H., a faculty member in the Public Health Sciences Division of Fred Hutch. "We know from several other studies that some high-dose dietary supplements -- that is, supplements that provide far more than the daily recommended intakes of micronutrients -- increase cancer risk. We knew this based on randomized, controlled, double-blinded studies for folate and beta carotene, and now we know it for vitamin E and selenium."

The data for the current analysis compared the effect of selenium and vitamin E, taken either alone or combined, on prostate cancer risk among 1,739 men who were diagnosed with prostate cancer and, for comparison purposes, a random sample of 3,117 men without prostate cancer who were matched to the cases by race and age.

The bottom line: The study showed no benefits to any men from either selenium or vitamin E supplements, and for significant proportions of men in the study these supplements were harmful.

"These supplements are popular -- especially vitamin E -- although so far no large, well-designed and well-conducted study has shown any benefits for preventing major chronic disease," Kristal said.

No known benefits -- only risks

"Men using these supplements should stop, period. Neither selenium nor vitamin E supplementation confers any known benefits -- only risks," he continued. "While there appear to be no risks from taking a standard multivitamin, the effects of high-dose single supplements are unpredictable, complex and often harmful. Taking a broad view of the recent scientific studies there is an emerging consistency about how we think about optimal intake of micronutrients. There are optimal levels, and these are often the levels obtained from a healthful diet, but either below or above the levels there are risks."


Story Source:

The above story is based on materials provided by Fred Hutchinson Cancer Research Center. Note: Materials may be edited for content and length.


Journal Reference:

  1. Alan R. Kristal, Amy K. Darke, J. Steven Morris, Catherine M. Tangen, Phyllis J. Goodman, Ian M. Thompson, Frank L. Meyskens, Jr, Gary E. Goodman, Lori M. Minasian, Howard L. Parnes, Scott M. Lippman, and Eric A. Klein. Baseline Selenium Status and Effects of Selenium and Vitamin E Supplementation on Prostate Cancer Risk. Journal of the National Cancer Institute, February 2014 DOI: 10.1093/jnci/djt456

Cite This Page:

Fred Hutchinson Cancer Research Center. "Selenium, vitamin E supplements can increase risk of prostate cancer in some men." ScienceDaily. ScienceDaily, 21 February 2014. <www.sciencedaily.com/releases/2014/02/140221184525.htm>.
Fred Hutchinson Cancer Research Center. (2014, February 21). Selenium, vitamin E supplements can increase risk of prostate cancer in some men. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2014/02/140221184525.htm
Fred Hutchinson Cancer Research Center. "Selenium, vitamin E supplements can increase risk of prostate cancer in some men." ScienceDaily. www.sciencedaily.com/releases/2014/02/140221184525.htm (accessed September 30, 2014).

Share This



More Health & Medicine News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Some Positive Ebola News: Outbreak 'Contained' In Nigeria

Some Positive Ebola News: Outbreak 'Contained' In Nigeria

Newsy (Sep. 30, 2014) The CDC says a new case of Ebola has not been reported in Nigeria for more than 21 days, leading to hopes the outbreak might be nearing its end. Video provided by Newsy
Powered by NewsLook.com
UN Ebola Mission Head: Immediate Action Is Crucial

UN Ebola Mission Head: Immediate Action Is Crucial

AFP (Sep. 30, 2014) The newly appointed head of the United Nations Mission for Ebola Emergency Response (UNMEER), Anthony Banbury, outlines operations to tackle the virus. Duration: 00:39 Video provided by AFP
Powered by NewsLook.com
CDC Confirms First Case of Ebola in US

CDC Confirms First Case of Ebola in US

AP (Sep. 30, 2014) The CDC has confirmed the first diagnosed case of Ebola in the United States. The patient is being treated at a Dallas hospital after traveling earlier this month from Liberia. (Sept. 30) Video provided by AP
Powered by NewsLook.com
New Breast Cancer Drug Extends Lives In Clinical Trial

New Breast Cancer Drug Extends Lives In Clinical Trial

Newsy (Sep. 30, 2014) In a clinical trial, breast cancer patients lived an average of 15 months longer when they received new drug Perjeta along with Herceptin. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins