Antioxidants: they favor lung cancer
One study found that antioxidants could promote the proliferation of cancer cells. In particular in the case of lung cancer.
A study released Wednesday, Jan. 29 in the American medical journal Science Translational Medicine shows that supplements of antioxidant vitamins accelerate the development of precancerous lesions and early lung cancer in mice and in human cells in the laboratory. For the first time , researchers were able to elucidate this mechanism.
Antioxidants such as vitamins A, C and E , help neutralize free radicals produced by the body . Free radicals ensure cleaning the body by removing continuously the defective or old cells. But too many , they become harmful due to their high oxidizing power can damage cells , accelerate aging and cause cancer.
Useful against free radicals infections–
Researchers have long thought that antioxidants can help prevent cancer tumors. And their benefits have often been touted . But more recent clinical studies suggest that they have no particular effect to prevent lung cancer . Worse, they may even increase the risk for vulnerable groups such as smokers.
The reason for this paradox remained obscure until now , says Professor Martin Bergö , co- director of the Cancer Centre at the Institute of Medicine, Göteborg , Sweden, and lead author of the work published Wednesday.
We found that these antioxidants have tripled the number of tumors and accelerated their aggression , killing the mouse twice as fast In this study, genetically modified to develop small tumors in the lungs mice were treated with vitamin E supplements and antioxidant drug.
” We found that these antioxidants have tripled the number of tumors and also greatly accelerated their aggressiveness ,” said Professor Bergö . ” And antioxidants killed these mice twice as fast,” he said, adding that the effects of these substances depended on the dosage. Thus, the more doses were high, the effects were greatest.
These findings were replicated in two different research models mouse and human lung cancer cells in vitro, said the researcher.
PROTEIN P53 . Antioxidants stimulate cancer progression by decreasing the amount of a key protein called ” p53 ” whose main role is to destroy the tumor cells so they do not damage DNA .
“When we eliminated this protein in mice and in cell lines of human lung cancer , antioxidants have been more effective ,” he has said.
Antioxidants have a deleterious effect–
Antioxidants have a deleterious effect because , by decreasing the levels of free radicals in the tumor at the same time they reduce the amount of p53 protein in the blood and give free rein to cancer cells to multiply.
This mechanism suggests that people with small lesions or undiagnosed tumors in the lungs , which is more likely in smokers should avoid supplements of antioxidants, said Professor Bergö .
Antioxidants could reduce the effect of chemotherapy–
It is unclear whether this adverse effect also occurs for other types of cancers and if these substances are beneficial in people at low risk to prevent cancerous tumors, he notes.
” It is still unclear whether antioxidants can reduce the risk of cancer in healthy people ,” says Professor Bergö .
PROSTATE: A study by researchers at the U.S. National Cancer Institute published in 2011 and conducted on 28,000 men aged 55 to 74 years , had already shown a link between beta-carotene , a powerful antioxidant found in many plants and used as form food supplement , and an aggressive form of prostate cancer .
These researchers also reminded that cancer treatments are designed to oxidize the cancer cells to destroy them. Antioxidants may therefore weaken their therapeutic action.