U.S. researchers warned that the anticancer action attributed to some antioxidant supplements has not been scientifically proven and claimed that their intake could even be counterproductive
According to a team of five scientists led by Maria Elena Martinez of the University of San Diego (California, USA), the supposed anti-cancer benefits of supplements such as beta carotene or vitamins C and E are “mostly a myth.”
In an article published in British Journal of the National Cancer Institute, experts say that these substances may even cause biological effects that promote the development of cancer.
The intake of antioxidants has become widespread since the popularization of the theory that prevent aging and certain diseases such as cancer, whose origin may have an important role oxidative stress in cells.
However, according to Martinez, people are being “deceived by the messages of supplement manufacturers,” which highlights the health benefits of their products, among which cancer prevention.
“The assumption that any dietary supplement is safe under all circumstances and in any amount is not supported empirically,” said Martinez.
In recent years, numerous animal studies have supported the theory that these supplements may reduce the risk of developing cancer, however, their conclusions have not yet been confirmed by randomized controlled trials, the “gold standard” in medicine, Martinez argued.
Only a small number of supplements has been subjected to such tests, Martinez said, and some studies have concluded that, in fact, the risk increased after taking these antioxidants.
“The intake of exogenous antioxidants can be a double edged sword. These components may act as pro-oxidants? The opposite effect to be obtained, or interfere in some body’s protective processes such as induction of apoptosis,” wrote the researchers in their paper.
Apoptosis, or programmed cell death is a process by which cells with problems cause their death.
Experimental studies have shown that different body tissues respond differently to each of the nutrients, “so an antioxidant linked to protection against cancer in a particular tissue may cause damage in another,” concludes the article.