Copper also plays a crucial role in maintaining healthy bones and preventing osteoporosis and osteopenia (low bone density). Connective tissue formation relies on copper, and our bones rely on connective tissues. Copper is also one of three minerals, along with manganese and zinc, that make up an extremely important antioxidant enzyme called superoxide dismutase – a key player in repairing cells and saving bones from oxidative damage. Superoxide dismutase also protects mitochondria, the “powerhouse” that generates the energy that our cells need to do their jobs.

According to Anna Foley, nutritionist at Nutrition Nation, copper is required to manufacture collagen, a major structural protein in the body. It’s needed to incorporate iron into red blood cells, thus preventing anaemia and is involved with the generation of energy from carbohydrates inside cells.

Copper has been found to be effective in extending the lifespan of patients afflicted with Lou Gehrig’s disease (also known as amyotrophic lateral sclerosis, ALS). This fatal neurological disease is characterised by the gradual degeneration of motor neurons. It leads to muscle weakness in the arms and legs, slurred speech, difficulty swallowing or chewing, respiratory or heart failure, and eventually death.

The average life expectancy of patients is two to five years. But an international team of researchers led by Joseph Beckman, a professor of biochemistry and biophysics at the College of Science at Oregon State University, have figured out a treatment that extends lifespan by nearly two years. By using a compound called copper (ATSM), the lifespan of ALS patients can be increased. Although they have only tested it on mice so far, they’re confident the treatment can be replicated with as much success in humans.

While a simple blood test can determine copper deficiency, symptoms include premature greying of hair, pale skin with lesions and dryness, dizziness or weakness, high blood pressure, diabetes, poor immunity, shortness of breath and a low white blood cell count and other blood irregularities. According to the Linus Pauling Institute, extended intake of 50mg or more of supplemental zinc per day can also lead to copper deficiencies.

According to the Food and Nutrition Board of the US Institute of Medicine, an adult’s estimated average dietary requirement for copper is about 700 micrograms per day. “Copper is not something the body can make, so we need to get it through our diet. The typical American diet, however, doesn’t include many green leafy vegetables. Asian diets, for example, have more foods rich in copper,” says Chang.

Copper supplements may be beneficial in treating or preventing copper deficiency. While there is no recommended dietary allowances for copper, it is advised to consume no more than 1.5 to 3mg per day in the form of copper tablets or capsule supplements. This should only be done under the supervision of your doctor. Antacids can hinder the absorption of copper in the body. This is due to the fact that the stomach requires an acidic state in order to properly absorb copper. Milk and egg proteins also have the same effect on copper absorption.

With copper readily available naturally in a variety of foods, supplements should be the last option. It would be a matter of concern if there were a decrease of whole foods in the diet and high consumption of fatty and processed foods. Besides, the copper water pipes that run through our homes, and copper cookware, leach copper into the water we drink and the food we eat.

Foods high in copper include:

seafood (oysters, squid, lobster, crab and octopus);

raw kale;

mushrooms, especially shiitake and cremini varieties;

seeds (sunflower, pumpkin, watermelon, squash and flaxseeds);

nuts (hazelnuts, brazil nuts, walnuts, pine nuts, pistachios, pecan and almonds);

beans (chickpeas, soybeans, adzuki beans, kidney beans and white beans);

dried fruit (prunes, apricots, currants, peaches, raisins and figs);

avocados;

goat’s cheese;

fermented soy foods (tempeh, miso and tofu);

and offal such as kidney and liver.

Sesame seeds have the highest copper content, followed by cashews and soybeans. Consuming a portion of any of these three foods will deliver at least 75 per cent of the daily copper requirement.

Whole grains are also important sources of copper. However, refining grains by removing their outer layers reduces their copper content significantly. For instance, refined white flour has less than half the copper content of the whole wheat kernel.

Similarly, cooking foods at high temperatures or browning them on the outside substantially reduces copper content. Lightly steaming or sautéing vegetables helps minimise their nutrient losses. For example, blanching spinach reduces the copper content by an insignificant fraction as compared to cooking it to a pulp, and cooking haricot beans removes half of their copper content.

Too much copper has been known to decrease thyroid function and alter other micronutrients such as calcium and sodium. Denise Fair, an accredited dietitian at Central Health Medical Practice in Hong Kong, says that while the chances of a copper overdose from organic or natural copper found in foods being “toxic” is extremely low, copper supplements and copper from other sources – usually metallic, such as electrical wires, plumbing pipes, brass fittings, copper intrauterine devices (IUDs), water fittings, cooking pans and copper coins – can cause copper toxicity and lead to physical symptoms such as gastrointestinal distress, vomiting, jaundice and hypotension.

Normally, copper is absorbed from food, and any excess is excreted through bile – a substance produced in the liver. But in people with Wilson’s disease, a rare inherited disorder that causes too much copper to accumulate in the liver, brain and other vital organs, it isn’t eliminated properly and accumulates, possibly to toxic life-threatening levels. When diagnosed early, Wilson’s disease is treatable, and many people with the disorder live normal lives.

Chang’s study of copper’s role in burning fat was based on lab tests of mice with Wilson’s disease; they found that the abnormal copper levels in the mice were associated with lower than normal lipid levels in the liver compared with the control group of mice.

The researchers treated the Wilson’s disease mice with isoproterenol, a beta agonist that breaks down fat into fatty acids. They noted that the mice with Wilson’s disease exhibited less fat-breakdown activity compared with control mice because of copper’s affinity to bind to phosphodiesterase 3, an enzyme that facilitates the breakdown of fat.