Supplementing with antioxidants such as vitamins C and E could increase the formation of blood vessels within lung cancer tumours, helping them to grow bigger and spread, according to a study in mice.

Taking antioxidant supplements such as vitamins C and E may cause lung cancers to grow bigger and spread by stimulating the formation of blood vessels within tumours, according to a study in mice. One researcher has stressed that people with the condition shouldn’t try to avoid these antioxidants in their diet, but getting more than they need via supplements could cause harm.

Martin Bergö at the Karolinska Institute in Sweden and his colleagues previously found that supplementing with the antioxidants vitamin E and n-acetylcysteine caused lung cancers to spread in mice.

To better understand how this might occur, Bergö and a new team of researchers studied mice with a murine-specific form of lung cancer and mice that had been implanted with human lung cancer cells. They supplemented the mice’s water with vitamin C, which the animals naturally produce, and vitamin E and n-acetylcysteine, which they get from their diet.

These supplements were administered at increasing doses, all of which caused the mice’s levels of these antioxidants to exceed what was necessary. “Today in society, you have a lot of people who eat healthily, they have some supplements, and then they may have a ginger shot and a smoothie,” says Bergö. “If you do all that, you could end up with the levels of doses that we’re talking about.”