The Relationship Between Nitric Oxide, Arginine, And The Heart

Nitric oxide (NO) plays an important role in cardiovascular health. The chemical is produced in the inner lining of the blood vessels (the endothelium). Numerous enzymes in the endothelium play a role in converting the amino acid arginine and oxygen into nitric oxide through a series of intermediate steps.

Nitric oxide signals the smooth muscle in the blood vessels to relax which improves blood flow Nitric oxide has beneficial effects on many heart disease risk factors. Several studies have demonstrated a link between hypertension and low levels of nitric oxide in the blood. It is thought that nitric oxide widens the blood vessels and arteries which reduces the pressure exerted by the blood on vessel walls. Nitric oxide may also play a role in preventing the hardening of the arteries (atherosclerosis).

While high levels of nitric oxide in the blood are thought to be associated with a lower risk of heart disease only a few lifestyle and dietary factors have been shown to influence nitric oxide production in the body.

It is believed that a diet rich in arginine increases the production of nitric oxide however studies have produced mixed results as to whether arginine can reduce the risk of coronary heart disease.

Arginine rich foods include dairy products such as milk, yogurt, cheese, meats such as beef, pork, chicken, turkey, tuna, salmon and lobster, bread – particularly whole grain breads, seeds, and nuts.

One study found that a high salt intake is associated with lower levels of nitric oxide in the blood. It is thought that salt impairs the ability of enzymes to convert arginine into nitric oxide.

A recent study found that nitrate and nitrite rich foods such as fruits, vegetables and cured meats can improve a patients outcome following a heart attack. Nitrites and nitrates are converted to nitric oxide during periods of oxygen deprivation such as during a heart attack, this in turn helps open clogged or closed arteries improving recovery after a heart attack.

High levels of exercise are thought to encourage the endothelium to produce more nitric oxide while diets high in saturated fat are thought to damage the endothelium and reduce nitric oxide production. Mediterranean style diets, which are both high in mono-unsaturated fat and low in saturated fat, are thought to improve both endothelial function and nitric oxide production.