Shiny new pennies remind us of copper’s value as currency, but it would take many bagfuls to buy a week’s worth of groceries. In our bodies, however, a little copper goes a long way. It’s an essential part of many enzymes, which spark the chemical reactions that sustain life. Copper-containing enzymes have diverse roles. They help us form strong, flexible connective tissue; produce energy; use iron; and manufacture cholesterol. "Copper has a direct effect on our bones, skin, heart, liver, blood, kidneys, thyroid, immune system, and just about every part in between," says Judith Turnlund, R.D., Ph.D., a trace mineral specialist at the U.S. Department of Agriculture (USDA) Western Human Nutrition Research Center in San Francisco.
Like a Chain-Link Fence
If you examine a chain-link fence, you’ll see that each strand of wire knits with the adjacent one, forming a strong mesh. In our bodies, copper helps link the long strands of proteins that make up the connective tissues throughout our bodies. It literally helps to hold us together.
"A copper-containing enzyme cross-links collagen, the body’s most important connective tissue, which is used to make skin, bones, lungs, and many other tissues," says Leslie Klevay, M.D., a doctor of hygiene and research medical officer at the USDA Human Nutrition Research Center in Grand Forks, North Dakota. Copper also cross-links elastin, a fiber that can stretch and rebound. It is found mostly in the skin and blood vessels.
Copper-deficient animals have weakened hearts and blood vessels and may die of heart failure. Lacking copper, the heart or the aorta, the main artery from the heart, may burst, Dr. Klevay says. Also, copper-deficient animals have bone defects that are very similar to osteoporosis. These dangers may lie in wait for humans, too. That’s one reason why nutritionists keep an eye on this significant trace mineral.
Enzymes That Lean on Copper
Two copper-containing enzymes are essential for our bodies to be able to use another important mineral—iron. These enzymes help move iron out of storage in cells lining the intestines or liver and transport it to the bone marrow, where it becomes part of the red blood cells produced there.
"If you don’t have enough copper, your body simply can’t use iron," Dr. Klevay says. Babies born with the inability to use copper and people who are copper-deficient develop anemia (insufficient red blood cells) because the copper shortage creates an iron shortage. When iron’s in short supply, the body doesn’t produce enough hemoglobin, the protein in red blood cells that carries oxygen.
SUPPLEMENTSNAPSHOT
| Copper May help: Bacterial, viral, and fungal infections and high cholesterol. Daily Value: 2 milligrams. Special instructions: Take as part of a multivitamin/mineral supplement that contains up to 2 milligrams of copper and less than 100 milligrams of vitamin C. If you want to take more vitamin C, take it separately; vita min C interferes with copper absorption and utilization. Who’s at risk for deficiency: People who take more than 30 milligrams a day of zinc, because zinc may be absorbed instead of copper; people who take more than 100 milligrams of vitamin C at the same time as copper supplements; people who don’t eat copper-rich foods; and those who consume large amounts of fructose, a component of both fruit and table sugar that can interfere with copper absorption. Good food sources: Chocolate, legumes, mushrooms, nuts, peanut butter, seeds, shellfish (especially cooked oysters), and whole grains. Cautions and possible side effects: Excess copper from supplements or from water from copper pipes can cause health problems. Signs include vomiting and diarrhea. Taking less than 10 milligrams occasionally is considered safe, but do not take more than 2 milligrams on a regular basis. Consult your doctor before taking higher amounts. |
Along with iron, copper is also needed for many reactions that transform the food we eat into energy that our bodies can use. In a series of chemical reactions, the food is broken down and transported to cells. Inside the cells, tiny powerhouses called mitochondria change the food into energy-containing molecules that can either be stored or hacked apart to release energy. This process involves a kind of assembly line of proteins, Dr. Klevay explains, and "the final protein in this line must contain two or three molecules of copper or the job of energy production stops before it is completed."
| What Are Trace Minerals? If you check the label on your multivitamin/mineral bottle, you may find some unfamiliar ingredients that seem somewhat suspicious, including such items as nickel, molybdenum, manganese, and vanadium. Some high-priced “designer” multis even contain silver or gold. These are all trace minerals. Like iron and copper, some of them, such as molybdenum and manganese, are essential to human health in tiny amounts. “Both are enzyme activators,” says Forrest Nielsen, Ph.D., director of the U.S. Department of Agriculture Human Nutrition Research Center in Grand Forks, North Dakota. These minerals are necessary for certain vital chemical reactions that take place in your body. Molybdenum is important because it activates the enzyme that produces uric acid—the substance that helps carry excess nitrogen out of your body when you urinate. Manganese is a component of an enzyme that plays a role in preventing degenerative disease. Lots of other trace minerals, even those found in multivitamins or sold singly, haven’t been proven essential. There’s some evidence that nickel, silicon, boron, and vanadium might be, but scientists still don’t know for sure. And the jury’s still out on minerals like germanium. We get more than enough of certain trace minerals such as molybdenum and silicon in our diets, Dr. Nielsen says. Others, such as manganese and boron, may be in short supply. Either way, it’s okay to take the 10 to 25 micrograms of any of these that you might find in a multivitamin/mineral tablet, he says. They won’t hurt you, and they may even be helpful. Some trace minerals come from unprocessed foods like whole grains and certain vegetables and fruits, but if you’re not likely to eat these foods, the supplements can easily make up any deficit. What’s not safe is using large amounts of trace mineral supplements for druglike effects. Vanadium, which supposedly builds muscle or prevents diabetes, and germanium, which has been said to prevent cancer and build the immune system, are sold singly. These supplements have shown little evidence of benefit, Dr. Nielsen says, and no studies have assessed the long-term effects of high amounts. “I am concerned because vanadium is toxic if you build up to a high enough quantity in your body,” says Dr. Nielsen. Furthermore, germanium might be contaminated with germanium dioxide, an inorganic form that can cause kidney damage. Worldwide, some 20 to 30 people have died from kidney damage caused by inorganic germanium. While it’s true that you can order it from the Internet, that doesn’t mean that you should. “This is not something to take lightly,” Dr. Nielsen says. |
The activity of the copper-containing enzyme lysyl oxidase, which cross-links collagen, is highest in cells that use the most energy—those in the heart, brain, liver, and kidneys. In animals, copper deficiency can produce a type of heart disease called cardiomyopathy.
Another copper-dependent enzyme, superoxide dismutase, plays a role as an antioxidant. Like vitamin E, it can neutralize the free-roaming, unstable molecules called free radicals. It circulates inside cells, soaking up free radicals that are produced as the cells break down waste products. Or it rushes to help immune cells called phagocytes, which "digest" bacteria that they swallow whole. With copper as an essential part of its wiring, superoxide dismutase helps cells stay young and protect themselves from bacterial, viral, fungal, and free radical onslaughts.
The Cholesterol Connection
Copper research has led to some close scrutiny of cholesterol metabolism. "Over 20 independent laboratories around the world now show that copper deficiency raises cholesterol levels in animals," says Dr. Klevay. When people are deprived of copper, their cholesterol levels shoot upward, similar to what happens in animals that are deprived of the mineral.
At least three enzymes seem to be involved, but the most important is HMG-coA reductase, found in the liver. Studies have found that this enzyme is overactive in copper-deficient animals. "What’s so interesting about this is that the newest cholesterol-lowering drugs, called statins, also act on HMG-coA reductase," Dr Klevay explains. "They are specifically designed to inhibit its activity, which lowers cholesterol very efficiently."
Does that mean that people with high cholesterol aren’t getting enough copper in their diets? "I think it’s certainly a possibility for some people, but it has yet to be studied," Dr. Klevay says.
A Penny Short?
Severe copper deficiency is extremely rare, and it takes more than a poor diet to cause it. Still, some researchers believe that marginal copper deficiency is more common than we know and that people may develop chronic illnesses such as heart disease and osteoporosis as a result. Supporting the connection to osteoporosis are two studies that were done with women who took copper supplements. Both showed that the women’s bone density improved when they had supplementation.
Most people get less than 1.5 milligrams a day of copper from foods, which is less than the Daily Value of 2 milligrams. You can increase your copper intake to recommended amounts by making appropriate food choices, Dr. Klevay says. Copper from foods is tolerated better than supplemental copper, so "you don’t want to go overboard with supplements," he cautions.
