The news about vitamins supplements hasn't been very encouraging.
Monday, an Annals of Internal Medicine study questioned the safety of long-term multivitamin use for women.
Tuesday, researchers are looking into the safety and efficacy of vitamin E for men.
Prior studies have shown a relationship between the supplements selenium and vitamin E and preventing prostate cancer.
In 2008, researchers from SELECT (Selenium and Vitamin E Cancer Prevention Trial) found that taking extra doses of these supplements did not help prevent the disease.
Researchers then continued following the men even though they stopped taking the supplements. Long-term follow-up results show that men who took vitamin E during the trial had an increased risk of developing prostate cancer.
Urologist Dr. Laura Crocitto supervised one of the trial sites at the City of Hope Medical Center. Researchers determined there was no benefit in taking these supplements. In fact, one of them could actually cause harm.
"The men in the vitamin-E-only group had a higher incidence, about a 17-percent increased risk of developing prostate cancer," said Crocitto.
"Men who took vitamin E alone at 400 international units a day in addition to a normal diet were at a 17-percent higher risk of developing prostate cancer," said Dr. Eric Klein, Cleveland Clinic.
The research provided by the Journal of the American Medical Association adds to what scientists have learned in previous vitamin studies on prostate cancer.
"So far there hasn't been one that has shows to be a benefit to prostate cancer to date," said Crocitto.
"These agents can have an effect, a biologic effect, even after you've stopped taking them," said Klein. "There just doesn't seem to be any reason to be taking vitamin E if you are a man over 55 or 60."
Researchers also showed in the SELECT study that neither vitamin E or selenium seem to prevent other health issues, including lung, colon or other cancers, cardiovascular disease or in helping people live longer.