It begins in the earth: A microscopic quantity of mineral is worn from the larger mass by the shearing forces of earth plate movement.
Water from thunderheads far overhead percolates down through the earth and washes the mineral into the waiting embrace of a plant’s underground network of roots. The thirsty plant absorbs the water and the mineral begins its journey to the surface and into the bodies of the animals who will eat the plant and the people who will eat the animals.
But once there, the real drama begins the linkage of mineral with body in an almost endless interplay that affects nearly every part of the human being, from heart and lungs to immune system and brain.
Minute but mighty
Zinc and copper are two of those minerals. Scientists call them trace minerals, meaning the body needs only small amounts. For a healthy adult, the Recommended Dietary Allowance (RDA) for zinc is 15 milligrams. For copper, there is no RDA, although 2 to 3 milligrams is considered the “safe and adequate” range.
The role of these two minerals in human health, however, is an enormous one that seems to grow larger with each new scientific inquiry especially with zinc.
“Zinc is very, very important,” says Ananda S. Prasad, M.D., professor of medicine at Wayne State University and an internationally recognized authority on zinc’s role in human health. “It is involved in more than 200 enzyme systems affecting almost all body functions, in growth and development and in certain immune system functions immune responses to viral, parasitic and fungal infections and wound healing.”
Copper is equally important. The body uses it to make red and white blood cells and collagen, the connective tissue that holds us together and is important for the formation of bone. It helps to make melanin, which helps us tan, and the myelin sheathing wrapped around our nerves as insulation. It also helps to regulate cholesterol metabolism and the heart.
A shortage of either mineral may have health impacts ranging from minor to major, even life-threatening ones. But zinc deficiency develops more often.
“Copper is very important, no question about it,” Dr. Prasad says. “It’s just that a copper deficiency doesn’t happen quite as often as zinc deficiency, which is actually fairly common.” So what happens if you don’t get enough zinc?
A mild shortage can produce numbing of your sense of taste and smell, skin changes (dryness, rashes), weight loss, fatigue and mental lethargy. More severe shortages, although almost unheard of in the American diet, can result in impaired growth, delayed wound healing, less resistance to disease, infertility and even death.
Dr. Prasad says that not enough information is available to estimate the magnitude of milder forms of zinc deficiency in the United States. But certain groups are at special risk: the elderly, pregnant women, nursing mothers, alcoholics, the still-growing young, those on a low-calorie reducing diet and anyone else who eats poorly. Vegetarians are a special case: Their diets eliminate meat, a rich source of zinc, and often include large amounts of cereal grains, which contain phytate, a compound that binds with zinc and partially blocks its absorption.
Similar unpleasantness occurs if you don’t get enough copper in your food. Experimentally documented effects of copper deficiency include anemia, weakened bones, increased cholesterol levels, degeneration of the central nervous system, weakness of arterial blood vessels and enlarged heart.
Meeting your daily requirement
What’s the best way to make sure you’re getting enough zinc and copper? The experts agree: Eat enough food from all four basic food groups and include those foods high in zinc and copper.
“The best source for both of these minerals is red meat, and organ meats in particular,” says Paul Saltman, Ph.D., a professor of biology at the University of California at San Diego and author of The California Nutrition Book.
Shellfish, particularly oysters, are also rich in zinc and copper. “But more important, the minerals in shellfish are readily assimilable your body can use them easily and efficiently,” says Dr. Saltman.
Too much is trouble
Dr. Prasad advises against zinc supplements providing more than 15 to 30 milligrams daily.
“If one is taking very high dosages approaching or above 50 milligrams or so a day it might pose a hazard,” he says. “I don’t recommend that except in special circumstances where a therapeutic effect of zinc is needed and then only on the advice of a physician.”
The dangers of too much zinc include anemia, a suppressed immune system and impaired copper absorption, with all the consequent risks to health posed by copper deficiency, such as increased cholesterol and cardiovascular disease.
Too much copper can be dangerous, too, producing damage to the brain, central nervous system and kidneys. The red metal can also reach toxic levels more quickly than zinc because the body needs less of it. But overdosing on either mineral is practically impossible unless one gulps supplements with total disregard for suggested daily doses.
“The best defense against too much or too little of any trace mineral,” notes Dr. Saltman, “is to maintain a varied diet and, when prudent, take a multi mineral supplement.
“I’m a great believer in good eating habits, in consuming a wide variety of food in reasonable amounts from all four food groups,” he says. “If you do that, and if you eat meats, you’ll get what you need of copper and zinc.”
