What do air pollution, the Nobel prize, Viagra and copper nutrition have in common? The answer: Nitric oxide. Nitric oxide is a deceptively simple molecule (chemical formula -- NO) that has complex and far reaching effects on the body. It is not to be confused with nitrous oxide (N2O), the anesthetic, which is otherwise known as ‘laughing gas'.
Twenty-five years ago, the only known effect of nitric oxide on human health was as an air pollutant emitted by automobile exhausts. About that time nitric oxide was also found to be the active component of nitroglycerin and other medications that were used to alleviate pain in patients with coronary heart disease. Over the next ten years, extensive study of blood vessel function showed that nitric oxide is naturally produced in the body and is responsible for regulating blood flow and blood pressure. In the last decade research on nitric oxide has mushroomed and shown that the compound plays a role not only in blood vessel function but also in transmission of signals in the nervous system, in heart contraction and in immune function.
So significant are the findings that a major scientific journal named nitric oxide the ‘Molecule of the Year' in 1992. The scientists that discovered the relationship between nitric oxide and blood vessel function earned the 1998 Nobel Prize in Physiology and Medicine. Because so many systems are affected by nitric oxide, potential medical applications of this research are boundless. They include treatments for high blood pressure, septic shock, arteriosclerosis (hardening of the arteries) and cancer. One such application is the development of Viagra, a drug that exaggerates the effect of naturally produced nitric oxide and thus aids men with erectile dysfunction.
What does nitric oxide have to do with copper nutrition? Recent studies performed on rats at the Grand Forks Human Nutrition Research Center, in conjunction with scientists at the University of Louisville, Ky., have shown that restricting the animals' intake of dietary copper impairs the action of nitric oxide on their blood vessels. This suggests that copper deficiency may contribute to reduced blood flow, and hence reduce oxygen delivery to tissues and increase blood pressure.
We have also recently found that, in the heart, nitric oxide production is elevated by reduced copper intake. Whereas nitric acid production in blood vessels is desirable, excess production in the heart can interfere with contractile function. Thus, by two different processes, dietary copper deficiency alters the action of nitric oxide, thereby interfering with functions of the heart and circulation. And because nitric oxide acts in other systems, such as the brain and immune system, it is likely that further research will reveal that known defects caused by copper deficiency in those systems relate to nitric oxide as well.
How do we prevent these undesirable effects of copper deficiency from happening to us? Consume a balanced diet containing foods high in copper -- liver, legumes, shellfish, meats, nuts, seeds and whole grains -- to achieve a copper intake of 1.5 to 3.0 milligrams per day.