Copper has many identities. It's long been used for cookware, electronics, jewelry and plumbing but copper has also been gaining attention over the past few years for its role in biological functions. Copper, we already know, is needed to form red blood cells, absorb iron, develop connective tissue and support the immune system. Now, a new study at the University of California further highlights copper's essential role in human health.
A research team at the Department of Energy's Lawrence Berkeley National Laboratory and at the University of California has found that copper plays a key role in metabolizing fat. "We find that copper is essential for breaking down fat cells so that they can be used for energy," says Chris Chang, the UC Berkeley professor of chemistry who led the research. The metal acts as a regulator, says Chang. "The more copper there is, the more the fat is broken down. We think it would be worthwhile to study whether a deficiency in this nutrient could be linked to obesity and obesity-related diseases." The researchers suggest this means copper might play a role in finding a natural way to burn fat.
According to the National Institutes of Health, an adult's estimated average dietary requirement for copper should be between 700 and 900 micrograms per day. Although copper is plentiful in foods such as oysters and other shellfish, leafy greens, mushrooms, seeds, nuts and beans, the board says that only around 25% of the U.S. population gets enough copper daily. "Copper is not something the body can make, so we need to get it through our diet," said Chang. "The typical American diet, however, doesn't include many green leafy vegetables. Asian diets have more foods rich in copper."
The researchers made the connection between copper and fat by looking at mice that had a genetic mutation that causes an accumulation of copper in the liver. This condition — known as Wilson's disease — is potentially fatal if left untreated. The team noticed their mice had larger than average deposits of fat compared with normal mice. Analysis revealed that the abnormal buildup of copper was accompanied by lower than normal lipid levels in the liver. Lipids are the building blocks of cells and can include "fats, oils, waxes, certain vitamins, hormones and most of the non-protein membrane of cells."
The researchers also found the mice with Wilson's disease had lower levels of copper in their white adipose tissue — or white fat — compared with that in normal mice that had corresponding levels of fat deposits. They then treated the Wilson's disease mice with the drug isoproterenol, which is known to aid the breakdown of fat into fatty acids — a process known as lipolysis. The mice with Wilson's disease showed less fat-breakdown activity than normal mice and this prompted the researchers to look at how copper affects lipolysis. They found that copper prevents the breakdown of fat by attaching itself to the chemical, phosphodiesterase, which makes the process possible. "When copper binds [to phosphodiesterase]," says Chang, "it's like a brake on a brake. That's why copper has a positive correlation with lipolysis."
This connection between copper absorption and fat is not that surprising, maintains Chang. "It had been noted in cattle that levels of copper in the feed would affect how fatty the meat was," he says. "This effect on fat deposits in animals was in the agricultural literature, but it hadn't been clear what the biochemical mechanisms were linking copper and fat." But Chang cautions against ingesting copper supplements as a result of these study results. Too much copper can lead to imbalances with other essential minerals, including zinc.
Excessive copper can cause damage to the liver, brain and other organs so caution is urged when considering adding more to your diet, especially in the form of supplements. As always, talk to your doctor before embarking on a new health regime. According to WebMD, a reasonably well-balanced diet would make copper supplements unnecessary for most people. Adults can maintain a healthy intake of copper by including cashews and walnuts, soy beans and tofu, mushrooms, tempeh, lentils and other pulses, leafy vegetables (such as kale, cabbage and Swiss chard), pineapple, shrimp, basil, thyme and garlic.
The new findings will appear in the July print issue of Nature Chemical Biology but are published in the online journal Nature this week. The co-lead authors of the study are Lakshmi Krishnamoorthy and Joseph Cotruvo Jr.