Heart Disease Risk Factor #1: Nitric Oxide

The role of nitric oxide in cardiovascular health.

from Cut Your Cholesterol

The same chemical responsible for men’s erections (and, indirectly, for the success of Viagra) also plays a vital role in the health of your arteries, and thus your heart.

The chemical is nitric oxide (NO), which is primarily produced in the blood vessels’ endothelium, or lining. There it increases blood flow, prevents fatty deposits from sticking to blood vessel walls, keeps walls from getting too thick and stiff, and prevents the arteries from narrowing.

“The lining of the vessel is very important for cardiac health,” says John P. Cooke, M.D., Ph.D., head of Stanford University’s vascular unit and one of the first researchers to pinpoint the role of NO in cardiovascular health. “When the endothelium is healthy it’s like Teflon, and things don’t stick.” When it’s unhealthy, it becomes more like Velcro, attracting blood-borne gunk like flies to flypaper.

All of the major culprits in heart disease — overweight, lack of exercise, smoking, high cholesterol, high blood pressure, high levels of homocysteine and lipoprotein (a) — damage the endothelium. And a damaged endothelium doesn’t make enough NO, which results in more damage in an increasingly dangerous spiral. “But we can restore endothelial health and the lining of the vessel through exercise and nutrition,” Dr. Cooke says. Certain nutritional supplements (like arginine) and drugs used to treat heart disease (like aspirin and statins) can also help.

By the Numbers

If doctors could measure endothelial function — how blood vessels behave — they would have a good indication of your nitric oxide production, and in fact, your overall risk for coronary heart disease (CHD). Measuring endothelial function is like asking your arteries, “How’s it going?” If the answer is “well,” your arteries are happy with the composition of the blood and are probably relatively free of plaque.

Doctors can measure endothelial function in various ways, most of which involve using ultrasound to measure changes in the diameter of certain arteries. This testing is usually used for research purposes only. But soon there may be a way to test endothelial function right in the doctor’s office. In late 2000 the FDA approved a new, noninvasive instrument called CVProfilor DO-2020 that can measure the elasticity of your arteries, an indication of NO production. Normal ranges vary depending on your age and sex. The test isn’t in routine use yet, but that day may be coming.

Quick Tips

  • Eat more foods that contain the amino acid arginine, from which NO is produced. This includes beans, soy, almonds, walnuts, oats, and such cold-water fish as salmon, tuna, and mackerel.
  • Cut your intake of saturated fat. Just one meal high in saturated fat can temporarily cut endothelial function almost in half.
  • Exercise. The increased blood flow that occurs during exercise encourages the endothelium to make more NO. Over the long term, if you exercise every day, your endothelial cells not only release more NO but also make more of the enzyme that converts arginine into NO.

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