Got copper? If not, beware of consequences

Patients who ignore the National Academy of Sciences (NAS) recommended dietary allowance (RDA) for the trace mineral copper may be putting themselves at risk for a variety of medical conditions. So says Carl Keen, chair of the department of nutrition and professor of nutrition/internal medicine at University of California, Davis.

In January 2001, NAS issued the following RDA for copper: adults, 0.9 mg; pregnant women, 1.0 mg.; nursing mothers, 1.3 mg.

"Every infant, child, and adult needs copper. According to a number of diet surveys, 20% to 25% of the population may currently be consuming a diet that [contains less copper] than is stipulated by the RDA," said Keen.

Keen explained that severe deficiencies of copper in pregnant women may result in congenital, bone, and cardiopulmonary abnormalities as well as neurological damage. "Copper is clearly involved in the movement of iron across some cell membranes. A copper deficiency may contribute to development of anemia and a failure to thrive in children," he said.

Patients can get copper by choosing foods that are rich in mineral, such as liver and kidney meats, chocolate, nuts, seeds, grains, and some shellfish, such as oysters.

Keen said it is important to have a well-balanced diet, but if a person wants "a safety net," he or she may want to consider taking a multivitamin mineral supplement. He does not recommend taking a copper supplement by itself. "A high level of anything can represent risk. There’s no reason to overdose on any essential nutrients," he said.

If patients wants to take a supplement, Keen recommended that they consult a physician. "If you have a good plant-based diet, you get a reasonable amount of copper. People run into problems when they have a diet rich in foods that are calorie dense but low in essential micronutrients," he said.

Supplements that contain high levels of zinc (50 mg or more) can interfere with copper absorption. "If you take zinc supplements that contain 30 mg of zinc, the Institute of Medicine recommends 2 mg of copper," advised Keen.

Copper is necessary for the functioning of numerous enzymes in the body. One of these enzymes, lysyl oxidase, helps cross-link connective tissue. The absence of this enzyme may cause hyperelasticity and more serious vascular defects, such as aneurisms. If a patient has a marginal copper deficiency and is a smoker, vessel walls may lose integrity, positioning the patient for poor vascular health, observed Keen.

Copper also affects the functioning of the enzyme copper zinc-superoxide dismutase, which helps to scavenge free radicals. If there is a copper deficiency and the activity of this enzyme becomes too low, there may be an increased risk for vascular and neurological diseases as well as an increased risk for certain cancers.

Yet another enzyme dependent on copper is cytochrome oxidase c. "This enzyme helps produce energy, specifically ATP. If there is no cytochrome functioning, cells can’t survive. Inadequate ATP can lead to multiple cellular problems," said Keen.

In summing up, Keen said, "Copper has multiple roles throughout the body, underscoring its importance as a nutrient in the diet."

Sandra Levy

Sandra Levy. Got copper? If not, beware of consequences.

Drug Topics

2001;16.