The association between high intake of fruit and vegetables and low incidence of certain cancers is well established.
Dietary antioxidants present in these foods are thought to decrease free radical attack on DNA and hence to protect against mutations that cause cancer, but this causal mechanism remains conjectural.
We have adopted a molecular epidemiological approach to this question, based on a modified alkaline single-cell gel electrophoresis assay ( « comet assay ») which specifically detects oxidation of pyrimidines in the DNA of human lymphocytes.
In a survey of men 50-59 years of age living in the northeast of Scotland, smokers initially showed significantly more base damage than nonsmokers.
Correlations between oxidative base damage and plasma concentrations of various antioxidants were generally negative but not statistically significant.
Supplementation of the diet for 20 weeks with vitamin C (100 mg/day), vitamin E (280 mg/day), and bêta-carotene (25 mg/day) resulted in a highly significant (P<0.002) decrease in endogenous oxidative base damage in the lymphocyte DNA of both smokers and nonsmokers.
In addition, lymphocytes of antioxidant-supplemented subjects showed an increased resistance to oxidative damage when challenged in vitro with H2O2.
These findings strongly support the hypothesis that fruit and vegetables exert a cancer-protective effect via a decrease in oxidative damage to DNA.
Mots-clés Pascal : Antioxydant, Fruit, Légume, Aliment, Ascorbique acide, alpha-Tocophérol, bêta-Carotène, Vitamine, Prévention, Radical libre, Oxydation, DNA, Lymphocyte, Homme, Fumeur, Cellule sanguine, Tumeur maligne, Anticarcinogène, Origine végétale, Epidémiologie moléculaire, Ecosse, Grande Bretagne, Royaume Uni, Europe
Mots-clés Pascal anglais : Antioxidant, Fruit, Vegetable, Food, Ascorbic acid, alpha-Tocopherol, Vitamin, Prevention, Free radical, Oxidation, DNA, Lymphocyte, Human, Smoker, Blood cell, Malignant tumor, Anticarcinogen, Plant origin, Molecular epidemiology, Scotland, Great Britain, United Kingdom, Europe
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 96-0195385
Code Inist : 002B04E05. Création : 199608.