Dietary antioxidants and the risk of CVDSpec 1.13
In short
Free radicals are highly reactive molecules that damage cells and oxidise LDL cholesterol, which promotes atherosclerosis. Dietary antioxidants such as vitamin C, vitamin E and carotenoids neutralise free radicals. Diets rich in fruit and vegetables are linked with lower CVD risk, but trials of antioxidant supplements have given conflicting results.
Free radicals are very reactive molecules, formed in normal metabolism and by factors such as tobacco smoke. They damage cell membranes and other molecules. In artery walls they damage endothelial cells and oxidise LDL cholesterol. Macrophages take up oxidised LDL more readily, forming foam cells, so oxidation speeds up the formation of atheroma.
Antioxidants are substances that neutralise free radicals, by donating electrons to them. Dietary antioxidants include vitamin C, vitamin E and carotenoids. They are found in fruit, vegetables, nuts and seeds. A higher intake of antioxidants is expected to reduce LDL oxidation and endothelial damage, and so reduce the risk of CVD.
The evidence
- Studies of populations show that people who eat more fruit and vegetables have a lower incidence of CVD.
- But this may be due to other differences (such as less saturated fat, more fibre or more exercise), so it does not show that antioxidants are the cause.
- Trials giving people antioxidant supplements have mostly found little or no benefit. A diet of whole foods may work through the combination of nutrients, not a single antioxidant.
A good answer to 'discuss the link' states the mechanism (neutralise free radicals, less oxidised LDL, less foam cell formation) and then comments on the conflicting evidence.
Written and checked against the Edexcel International A Level Biology (YBI11) specification · Updated October 2026