Extract from “Reverse Heart Disease Now” by Drs Stephen . Sinatra and James C. Roberts (leading cardiologists) with Martin Zucker (pp 109 – 111):
“L-arginine
“The most important determinant of cardiovascular well-being – or lack of it – is the biochemical health of the endothelium, the single layer of cells lining the interior wall of the blood vessels. You’ll likely be fine if you have a significant narrowing of your coronary arteries but good endothelial function. If you have a 40 percent narrowing but terrible endothelial function, your prospects are poor. Biochemistry supercedes (US spelling?) anatomy. It determines cardiovascular life or death.
“By biochemistry, we mean the ability of these cells to function as hormone factories, particularly to produce nitric oxide, a compound that relaxes the arteries, keeps them flexible, and promotes blood flow. Nitroglycerin, the traditional medication to relieve chest pains, is simply a drug form of nitric oxide.
“As we age, we make less nitric oxide. Deficiency permits blood vessels to constrict and lose their flexibility, contributing to vessel stiffness, inflammation and plaque buildup, and hypertension. Moreover, a vicious circle develops: increased blood pressure and inflammation impair the ability of the endothelial cells to make nitric oxide. …..
“To make nitric oxide, the body needs L-arginine, an amino acid found in many foods 
such as dairy products, meat, poultry, fish, nuts, seeds, and chocolate. If you take in a lot of L-arginine, you make more nitric oxide and obtain greater protection against the damaging effects of diabetes, smoking, high blood pressure, free radical stress, and many of the problems related to CVD. ……
“L-arginine was first found to boost nitric oxide and arterial physiology in a series of Stanford studies published in 1992. Rabbits with high cholesterol levels supplemented with L-arginine developed significant improvement in arterial and endothelial function compared to nonsupplemented animals. L-arginine appeared to help defuse the biochemical events that initiate atherosclerosis.
“Later, in another rabbit study, German researchers showed that L-arginine supplementation started after the formation of plaque not only improved arterial dilation but also stopped plaque progression. Moreover, they found that L-arginine had a much greater effect than Mevacor, a popular statin drug, which actually increased endothelial free radical activity.
“Other studies have shown that L-arginine:
- Reduces endothelial dysfunction irrespective of the cause
- Provides an antioxidant effect
- Blocks LDL oxidation
- Blocks platelet clumping and white cell adhesion to the vascular wall
- Decreases angina frequency and nitroglycerin need
- Improves symptoms in patients with heart failure
- Improves outcome following heart attack
- Improves functional status in pateients with coronary and/or lower extremity vascular blockages.”