Women with the val/val type of the gene COMT who took vitamin E had a 15 percent higher risk of developing cancer versus those with met/met, who had a 14 percent lower risk. Photo by Gio.tto/Shutterstock

Jan. 8 (UPI) -- A genetic variant may determine whether vitamin E can lower people's risk for developing cancer, a new study says.

A gene known as catechol-O-methyltransferase, or COMT, is the key to deciding if vitamin E lowers or raises risk of developing cancer, a study published Tuesday in The Journal of the National Cancer Institute.


"Observational studies of people taking vitamin E have reported benefits, and studies in animal models have suggested a protective effect, but when vitamin E supplements were brought into placebo-controlled clinical trials, the results were null," Kathryn Hall, researcher from the Division of Preventive Medicine at the Brigham and Women's Hospital, said in a news release.

"This made it easy to assume that vitamin E just doesn't work. But what we've found is that it may have been protective in some and not in others, and that genetic variation is linked to these outcomes."

COMT is made up of three genetic types: met/met, val/met and val/val. Among those who participated in the study, women with val/val who took vitamin E had a 15 percent higher risk of developing cancer versus those with met/met, who had a 14 percent lower risk.

That's probably because enzymes are three to four times more active in people val/val than with met/met, according to the researchers.

The researchers also found similar percentages for various types of cancer, like breast, colorectal, lung and uterine.

Past research from Hall has also found that certain genetic variations of COMT may even cause cardiovascular disease.

"Significant gene-drug interactions are hard to find, and this one is particularly striking. Now we need to understand which cancers are affected, why and how, and these results encourage us to pursue this with robust and rigorous curiosity," Hall said.