The idea that dietary supplements can help people avoid cancer could be a harmful “two-edged sword”, researchers have said.
According to a group of US scientists there is no clear evidence to support the idea that supplement pills decreased the chances of healthy people developing cancer.
In fact, the scientists said that beta carotene and vitamins C and E and other such antioxidants may even have biological effects that encourage cancer.
It is commonly thought that antioxidants ward off free radicals - harmful rogue oxygen molecules that attack cell membranes, proteins and DNA, causing oxidative stress - which have been closely linked to heart disease and cancer.
However, in the article Dietary Supplements and Cancer Prevention: balancing potential benefits against proven harms, published in the Journal of the National Cancer Institute, the group of US scientists claim the beneficial impact of antioxidants in warding off cancer is generally a fantasy.
They wrote that individuals were often given the false impression of the healthiness and cancer preventative advantages of antioxidant products by “messages from supplement manufactures”.
Headed by Dr Maria Elena Martinez of the University of California in San Diego, the group of five scientists wrote: “The assumption that any dietary supplement is safe under all circumstances and in all quantities is no longer empirically reasonable.”
- Martinez ME, et al. Dietary Supplements and Cancer Prevention: Balancing Potential Benefits Against Proven Harms. Journal of the National Cancer Institute 2012; Advance online publication.