Antioxidants are supposed to keep your cells healthy. However, a new study adds to a growing body of research that suggests that supplements like vitamin E and beta-carotene have a harmful effect on cancer.
The study was conducted on mice and shows that antioxidants can change cells in ways that fuel the spread of malignant melanoma to different parts of the body. The progression makes the disease even more deadly.
Earlier studies of antioxidant supplement use have also hinted at a cancer-promoting effect. In 1994, a large trial reported that daily megadoses of the antioxidant beta-carotene increase the risk of lung cancer in male smokers by 18%.
A 1996 trial discovered that high-dose beta-carotene and retinol increased lung cancer by 28% in smokers and worked exposed to asbestos.
A 2011 trial involving more than 35,500 men over 50 years old found that large doses of vitamin E increased the risk of prostate cancer by 17%.
These findings are contrary to the conventional wisdom that antioxidants should lower cancer risk by neutralizing cell-damaging, cancer-causing free radicals.
However, researchers now believe that high levels of antioxidants also protect cancer cells from these same free radicals.
During this recent study, antioxidant N-acetylcyteine was fed to mice that had been genetically engineered to be susceptible to melanoma. Although the treated mice did not develop more skin tumors than similar mice that had not been fed the antioxidants, they developed twice as many tumors in their lymph nodes. That is a hallmark of the spread of cancer.
When researchers added a form of vitamin E to cultured human melanoma cells, they were able to confirm that the antioxidants improved the cells’ ability to move and invade a nearby membrane
The medical advice at the moment is tentative. More research is necessary to bolster this hypothesis and understand exactly how antioxidants affect cancer cells in people.