Other interested parties take a more "wait-and-see" response: "We would need to see data from much longer studies that look at the total health impact of selenium or vitamin E supplements before we could say if the small effects on the chance of getting prostate cancer suggested by this study outweigh any general benefits to health," said Dr. Matthew Hobbs, deputy director at Prostate Cancer UK, according to The Guardian.
A complex relationship
A look at the existing research suggests that Dr. Kristal's statement may oversimplify what appears to be a very complex relationship. While the relative benefits of healthy eating versus supplementation is also part of the ongoing conversation, studies have already associated these nutrients with a range of health benefits:
Vitamin E is thought to support a healthy immune system, joints, skin, and other functions.
Selenium plays a role in a number of body systems and conditions as varied as asthma, depression, artery health, and colon cancer prevention.
What's the bottom line?
What's needed, of course, is more research--preferably a clinical study designed to identify cause and effect relationships, rather than a study like this new one that examined data after the fact. While we wait for this work, the conclusion reached by the new study's authors is reasonable for many men: those over age 55 "should avoid supplementation with either vitamin E or selenium at doses that exceed recommended dietary intakes." There may be exceptions to that, which should be discussed with a knowledgeable doctor.
Further, Aisle7 Chief Science Editor Alan Gaby, MD, says that people who want to supplement with vitamin E would be better advised to try mixed tocopherols, as the pure alpha-tocopherol in the amounts used in this and most studies depletes gamma-tocopherol, which may in turn have unwanted effects on health. Read the label when choosing vitamin E supplements and look for mixed tocopherols.
(JNCI 2014; Advance access Feb 22; DOI:10.1093/jnci/djt456)