Now there is additional evidence of the connection between the intake of antioxidant supplements and increased tumor growth. Experiments on animals and human cancer tissue confirm that addition of some antioxidants increases the growth of the severe malignant melanoma type of skin cancer.
"This is not the way to treat cancer. In the best case the treatment makes no difference, but it can also exacerbate the disease," says Kristell Le Gal Beneroso, who has a PhD in medicine from Sahlgrenska Academy, University of Gothenburg, Sweden.
The idea that antioxidants protect against cancer because they neutralize so-called free radicals has been challenged in several studies in recent years. It has become apparent that antioxidants protect not only healthy cells in the body, but also cancer cells.
According to previous studies from the current research team in Gothenburg headed by Professor Martin Bergö, the spread of both lung cancer and malignant melanoma accelerates with the addition of certain antioxidants. This takes the form of an increase in the number of metastases or daughter tumors.
In work on her thesis, Kristell Le Gal Beneroso went a step farther and examined how lung cancer and malignant melanoma in mice and human cancer cells respond to the addition of certain compounds of antioxidants. The compounds bind to the cells' mitochondria, which are the main producers of free radicals.
"The theory behind this was that by binding the mitochondria, the production of free radicals could be reduced, blocking the DNA damage that free radicals cause and that, by extension, can accumulate and lead to cancer," says Le Gal Beneroso.