Long prized as a malleable, conductive metal used in cookware, electronics, jewelry and plumbing, copper has been gaining increasing attention over the past decade for its role in certain biological functions. It has been known that copper is needed to form red blood cells, absorb iron, develop connective tissue and support the immune system.
A new study is further burnishing copper's reputation as an essential nutrient for human physiology. A research team scientists has found in the journal Nature Chemical Biology for the first time copper's role in fat metabolism.
The researchers made the copper-fat link using mice with a genetic mutation that causes the accumulation of copper in the liver. Notably, these mice have larger than average deposits of fat compared with normal mice.
The inherited condition, known as Wilson's disease, also occurs in humans and is potentially fatal if left untreated.
Analysis of the mice with Wilson's disease revealed that the abnormal buildup of copper was accompanied by lower than normal lipid levels in the liver compared with control groups of mice. The researchers also found that the white adipose tissue, or white fat, of the mice with Wilson's disease had lower levels of copper compared with the control mice and correspondingly higher levels of fat deposits.
They then treated the Wilson's disease mice with isoproterenol, a beta agonist known to induce lipolysis, the breakdown of fat into fatty acids, through the cyclic adenosine monophosphate (cAMP) signaling pathway. They noted that the mice with Wilson's disease exhibited less fat-breakdown activity compared with control mice.
The results prompted the researchers to conduct cell culture analyses to clarify the mechanism by which copper influences lipolysis. The researchers used inductively coupled plasma mass spectroscopy (ICP-MS) equipment at Berkeley Lab to measure levels of copper in fat tissue.
They found that copper binds to phosphodiesterase 3, or PDE3, an enzyme that binds to cAMP, halting cAMP's ability to facilitate the breakdown of fat.
"When copper binds phosphodiesterase, it's like a brake on a brake," said the senior author. "That's why copper has a positive correlation with lipolysis."
"We find that copper is essential for breaking down fat cells so that they can be used for energy," said senior author. "It acts as a regulator. 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."
Author said that copper could potentially play a role in restoring a natural way to burn fat. The nutrient is plentiful in foods such as oysters and other shellfish, leafy greens, mushrooms, seeds, nuts and beans.
According to the Food and Nutrition Board of the Institute of Medicine, an adult's estimated average dietary requirement for copper is about 700 micrograms per day. The Food and Nutrition Board also found that only 25 percent 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 the auhtor. "The typical American diet, however, doesn't include many green leafy vegetables. Asian diets, for example, have more foods rich in copper."
But author 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.
Copper is key in burning fat
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