Boston, MA—A study performed by Brigham and Women’s hospital found that genetic variations influenced whether vitamin E decreased or increased risk of developing cancer during and after the study periods, according to Science Daily.

Kathryn Hall, Ph.D., MPH, from the Division of Preventative Medicine at Brigham, was quoted as saying, “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. 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.

Genetic differences in the enzyme catechol-O-methyltransferase (COMT) affect how vitamin E is processed by the body, which affects in turn the effects of vitamin E on cardiovascular risk and cancer.

Hall and her co-authors used data from the 10-year-long WHS/WGHS trial and 10years immediately following the trial’s conclusion. They found that women with the least active version of COMT who took vitamin E had cancer rates 14% lower than the placebo group, whereas women with the most active version of COMT had cancer rates 15% higher than the placebo group.

The COMT gene can be tested. LabCorp tests it, and individuals canbuy a cheek swabtest that checks precisely the region of the gene that determines a person’s reaction to vitamin E. The association between the COMT gene and vitamin E reaction might be newly discovered, but the significance of the gene is not.

Hall told Science Daily, “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.”