Evidence of benefit still fragmentary

A longstanding tenet of nutrition holds that people with diets rich in fruits and vegetables enjoy better health than people eating few fruits and vegetables. Consequently, research has sought the components or compounds responsible for this apparent health benefit. Much of that research currently focuses on dietary antioxidants, fuelled by our growing appreciation that damaging oxidative processes are a common biochemical link between otherwise pathophysiologically distinct diseases.1 For example, the development of early atherosclerotic lesions is now thought to be specifically promoted by low density lipoprotein particles that have been oxidatively modified,2 3 and oxidative damage to nucleic acids may have an important role in carcinogenesis.

Dietary antioxidants, which complement the actions of enzymatic antioxidants, are now widely recognised as including (alpha) tocopherol (vitamin E), ascorbic acid (vitamin C), and β carotene (a precursor of vitamin A). Perhaps flavonoids should now be added to this list. The article by Knekt et al in this issue of the BMJ (p 478)4 joins two other epidemiological reports5 6 in suggesting a role …