OBJECTIVE: The British Nutrition Foundation was recently commissioned by the 
Food Standards Agency to conduct a review of the government's research programme 
on Antioxidants in Food. Part of this work involved an independent review of the 
scientific literature on the role of antioxidants in chronic disease prevention, 
which is presented in this paper.
BACKGROUND: There is consistent evidence that diets rich in fruit and vegetables 
and other plant foods are associated with moderately lower overall mortality 
rates and lower death rates from cardiovascular disease and some types of 
cancer. The 'antioxidant hypothesis' proposes that vitamin C, vitamin E, 
carotenoids and other antioxidant nutrients afford protection against chronic 
diseases by decreasing oxidative damage.
RESULTS: Although scientific rationale and observational studies have been 
convincing, randomised primary and secondary intervention trials have failed to 
show any consistent benefit from the use of antioxidant supplements on 
cardiovascular disease or cancer risk, with some trials even suggesting possible 
harm in certain subgroups. These trials have usually involved the administration 
of single antioxidant nutrients given at relatively high doses. The results of 
trials investigating the effect of a balanced combination of antioxidants at 
levels achievable by diet are awaited.
CONCLUSION: The suggestion that antioxidant supplements can prevent chronic 
diseases has not been proved or consistently supported by the findings of 
published intervention trials. Further evidence regarding the efficacy, safety 
and appropriate dosage of antioxidants in relation to chronic disease is needed. 
The most prudent public health advice remains to increase the consumption of 
plant foods, as such dietary patterns are associated with reduced risk of 
chronic disease.