Walnuts help to keep blood vessels 'dilated' in people with high cholesterol levels

Coronary heart disease is a condition characterised by narrowing of the arteries which may increase the risk of triggering a blood clot. Narrowing of arteries is caused by:
1) fatty deposits or plaques, found in atherosclerosis
2) blood vessel lining (or endothelium) dysfunction eg. when arteries become damaged and narrowed by atherosclerosis they also become 'twitchy' and more prone to spasm; vessels react by contracting and reducing vessel diameter (or vasoconstriction) which increases the risk of blockage. It therefore follows that anything that relaxes blood vessels (or vasodilation) should decrease the risk of a blockage.

A study published in Circulation April 6 2004 by Ros and colleagues showed that
daily consumption of walnuts by people with high cholesterol levels, not only reduced blood cholesterol levels, but also improved brachial artery vasodilation (endothelium-dependent vasodilation). Twenty-one men and women were placed on either a cholesterol-lowering Mediterranean diet or a walnut diet of similar energy and fat content in which walnuts replaced about 32% of the energy from monounsaturated fat. Subjects followed the diets for 4 weeks. Compared with the Mediterranean diet, the walnut diet was more effective at relaxing the brachial artery. This finding might explain the cardioprotective effect of nut intake beyond cholesterol lowering.

To find out more about how nuts may act to protect against heart disease:
HEC article on Heart disease
HEC article on Nuts

Last Updated: April 2004