Antioxidants in food: a summary of the review conducted for the Food Standards Agency

Abstract

The British Nutrition Foundation recently completed a critical review of the Food Standards Agency's Antioxidants in Food program. The projects funded as part of this program, which addressed biomarkers of oxidative damage, gene expression, supplementation with dietary antioxidants and bioavailability of dietary antioxidants, were evaluated and set within an international context. This paper summarises the findings and recommendations of this review. Although there is a substantial body of evidence that a diet rich in plant foods (particularly fruit and vegetables) conveys health benefits, intervention trials have been unable to demonstrate any causal link between antioxidant supplementation and chronic disease. Difficulties in undertaking such trials with long‐term disease endpoints, as is the case with cancer and cardiovascular disease, has led to considerable interest in the identification of robust biomarkers of oxidative damage. However, the relevance of these biomarkers to disease risk remains an issue and little is known about what might be regarded as a normal level of endogenous oxidative damage. The review concluded that the research program should focus on a wider scope of potential mechanisms, rather than antioxidant mechanisms alone. It also recommended that more research is needed on the bioavailability and tissue distribution of antioxidants and the impact of factors such as genotype, age and illness before embarking on a multicentre intervention trial.

Antioxidant and Pro-Oxidant Effects of Polyphenolic Compounds and Structure-Activity Relationship Evidence

“…Because the antioxidants are not occurring isolated in food items, other constituents may influence their activity. It should also be noted that their metabolites may have more relevance in vivo assays than the molecule itself, in terms of concentration or biological activity (Buttriss et al, 2002).…”

The Food Standards Agency's antioxidants in food programme – a summary*

“…To date much attention has focused on the potential for prevention by antioxidants of oxidative damage to DNA, in particular, but also to proteins and lipids. This damage is caused by interaction with oxygen or nitrogen free radicals (Buttriss et al ., 2002a, b) and is thought to be associated with mutations to DNA which, if not repaired, could lead to cancer. Similarly, damage to lipids and lipoproteins has been linked with atherosclerosis.…”

Antioxidants: An Overview on the Natural and Synthetic Types

“…The two possible pathways are chain-breaking and preventive. 25 Chain-breaking: When a free radical release or abstracts an electron, a second radical is formed. This molecule then turns around and does the same thing to a third molecule, continuing to generate more unstable products.…”