Consuming antioxidants to prevent lung cancer is a bad idea. One study reports that these products accelerate the growth and aggressiveness of lung tumors.
Antioxidants, good for your health. This is the slogan that has dominated for several years. A study, published on January 29 in Science Translational Medicine, tempers the surrounding enthusiasm. According to the results obtained by researchers at the University of Gothenburg (Sweden), a high dose of these products in patients at risk of lung cancer, such as smokers, can be dangerous: it promotes the growth of precancerous lesions and tumors.
Death twice as fast
Antioxidants are chemical compounds that delay the deterioration of cells. They prevent the formation of molecules called “reactive molecular oxygen” (RMO) which attack cells. The best known antioxidants are vitamins A, C and E as well as drugs, such as acetylcysteine used in the treatment of chronic obstructive pulmonary disease (COPD). Scientists have long believed that antioxidants also help fight cancer. But recent clinical trials have shown that they are not effective in this use. Worse: in some patients, they increase the risk of cancer.
Researchers at Gothenburg University studied the effects of vitamin E and acetylcysteine in mice with lung cancer, as well as on human cells. They used the usual doses in order to be able to estimate the damage in humans. They found that taking antioxidants accelerates the progression of cancer. “Antioxidants triple the number of tumors and also the aggressiveness of tumors,” explains Dr. Martin Bergö, author of the study. “And the antioxidants killed the mice twice as fast. Their effects were dose dependent, meaning that if given a low dose the tumors grew a bit, and if given a high dose they grew rapidly. »Antioxidants reduce the level of active molecular oxygen in tumors. This leads to DNA damage, and the amount of p53 protein decreases. However, this protein helps fight against tumors. When not present, the researchers observed, the products no longer had any effect on tumors.
Tobacco and COPD: beware of the risks
Two conclusions can be drawn from these results. “The first is that if you have lung cancer, or if you are at risk of developing one, if you smoke for example or if you have a lung disease like COPD (…), then take antioxidants can be harmful, and it could accelerate the growth of a tumor ”, anticipated Dr. Bergö at a press conference. He recalled that a large number of patients at risk can be carriers of a small tumor without knowing it. Consuming antioxidants could trigger premature growth of it. It therefore advises against patients at risk of taking it.
“The second implication concerns patients with a lung disease, COPD. These patients take acetylcysteine as a medication to reduce mucus production in order to breathe easier. Because acetylcysteine has antioxidant properties, we believe that its use in this group of patients should be carefully evaluated, ”warns Martin Bergö. The University of Gothenburg team is now investigating whether these findings can be extended to other types of cancer. They consider that the effectiveness of antioxidants in preventing cancer remains to be proven.
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