Taking vitamin E and selenium supplements may put men at significantly increased risk of developing life-threatening prostate cancer, US researchers have warned.
“Men using these supplements should stop, period,” commented Dr Alan Kristal, of the Fred Hutchinson Cancer Research Centre in Seattle, which has been running a follow up trial to the 2005 SELECT prostate cancer prevention study.
The SELECT trial was set up to test the findings of earlier studies which suggested that selenium and vitamin E (alone or in combination) might reduce the risk of developing prostate cancer by 60 percent and 30 percent, respectively. The trial, which involved 35,000 men, was stopped in 2008 when researchers found the men taking the supplements seemed to be at a greater risk of developing aggressive prostate cancer – although it wasn’t clear if supplementation was the cause.
The new review of data from the SELECT trial, published this month in the Journal of the National Cancer Institute, found that men who already had high concentrations of selenium in their bodies nearly doubled their risk of aggressive prostate cancer if they took selenium supplements. The researchers also found that vitamin E supplements more than doubled a man’s prostate cancer risk if he had low concentrations of selenium in his body
In their study the researchers warn that “men aged greater than 55 should avoid supplementation with either vitamin E or selenium at doses that exceed recommended dietary intakes”.