We only need a tiny amount of copper each day, but its impact on our bones, immune system and brain is mighty. Photo / 123rf
This essential mineral is often overlooked and our bodies can’t produce it, which means dietary sources are key.
The importance of eating enough calcium for our bones and teeth is well-understood. The same is true for omega-3 fatty acids and a healthy brain. However, there’s a little-known trace mineral that’s critical to our health. We only need a tiny amount of it each day, but its impact on our bones, immune system and brain is mighty. This all-important trace mineral is copper.
A recent study in Scientific Reports found that a copper-rich diet was linked to improved cognitive function in adults aged 60 and over in the United States. Whilst a copper deficiency (also known as hypocupremia) is rare, it can be debilitating.
Ensuring we eat enough copper is undoubtedly important – so how much of it do we need, what are the signs of deficiency, and what can we eat to boost our intake?
“Copper is an essential and important trace mineral for our bodies which is often overlooked,” says Dr Naila Aslam, a GP at Central Health London. We need small amounts of copper to function properly, yet our bodies can’t produce it – which means we must get it from our diet.
It plays a key role in “energy production within cells, immune system function, red blood cell synthesis, the formation of collagen and healthy bones, and brain development”, Aslam explains.
Both copper and iron play an important role in the formation and production of red blood cells. In fact, iron actually needs copper to be properly used in the body, Aslam explains.
If the body doesn’t have enough copper, iron absorption and utilisation can be impaired, potentially leading to anaemia. This is because ceruloplasmin, a copper-containing protein, is crucial in binding iron to transferrin, the protein that transports it in the bloodstream to various cells. “Our body is very capable of maintaining the right balance of copper and iron,” Aslam says.
According to UK dietary guidelines, we need 1.2mg of copper a day. Generally, that amount is easily achievable from a well-balanced diet, Aslam says. “Copper deficiency is pretty rare as an isolated event and it’s difficult to diagnose because the symptoms are vague and overlap with other conditions,” she adds, however, “there are certain conditions and risk factors that are more commonly associated with a deficiency”.
“One of the most common places we see a copper deficiency is if someone has had stomach surgery – so a gastric bypass or a gastrectomy,” says Clare Thornton-Wood, a specialist registered dietitian.
This is because 30 to 40% of dietary copper is typically absorbed throughout the gastrointestinal tract, particularly in the duodenum in the small intestine. After certain bariatric surgeries, food bypasses the duodenum, resulting in significantly reduced copper absorption.
People with coeliac disease or inflammatory bowel disease (IBD) may also be deficient in copper “because they often have problems with absorbing their nutrients” as a result of small intestine damage and inflammation, Thornton-Wood explains.
Excessive zinc intake – often from supplements – can also prevent the absorption of copper. Zinc is vital for immune support and skin health, and UK guidelines state that men need 9.5mg a day, whilst women need 7mg a day. However, if you consume too much zinc, “it can cause a copper deficiency, because zinc competes with copper for absorption in the gut”, Aslam explains.
Fortunately, this is fairly rare, as most over-the-counter supplements are 10 to 15mg. Higher strength supplements may cause a problem if taken for a long period of time. These are sometimes recommended for people “with concerns about skin, hair loss or a confirmed deficiency”, Aslam explains.
You may experience a zinc deficiency if you have certain gastrointestinal difficulties such as coeliac disease, other malabsorption conditions, or are healing from severe burns. However, most people consume enough zinc from a well-balanced diet.
Copper deficiency can also be caused by Menkes disease (a rare inherited genetic disorder), Thornton-Wood says. It’s caused by a defect in the ATP7A gene, which plays a vital role in the transportation of copper. As a result, the brain and other parts of the body don’t get enough copper, while it builds up in the small intestines and kidneys. Affected individuals exhibit low copper levels in the blood, which can lead to a range of neurological problems.
The symptoms of a copper deficiency can overlap with other conditions, Aslam says. However, common signs include:
Persistent fatigue
“On the NHS, we don’t routinely test for copper,” Aslam says. “However, if you come to me after gastric surgery, have other risk factors or you’re taking supplements and still complaining of fatigue, I would likely test for copper.”
Several rodent studies have found that copper deficiency may also cause anaemia, because of copper’s important role in iron absorption. “Copper deficiency can therefore present as iron deficiency anaemia,” Aslam explains.
Numb fingers and toes
A copper deficiency can present with neurological symptoms and may mimic a B12 deficiency, Aslam says. “Symptoms include numbness in your fingertips and toes or a tingling sensation in your legs, hands and feet.” This is because copper plays a role in maintaining nerve health and function. A 2022 case report in Cureus details a 50-year-old woman with copper deficiency who has extreme weakness, numbness and tingling in her arms and legs.
Difficulty with balance
Copper plays a crucial role in maintaining a healthy nervous system. When copper levels are low, it can disrupt the signals between the brain and body, leading to difficulties with coordination and balance. People with copper deficiency may also find it harder to walk properly because of this.
Weakened bones
Copper is crucial for bone health because it’s involved in collagen synthesis and the activity of enzymes that help minerals attach to bone protein. Therefore, a deficiency can make bones more fragile. In fact, an analysis of eight studies including over 2000 people found that those with osteoporosis had lower levels of copper than healthy adults.
Frequent sickness
People who are often unwell may have a copper deficiency because copper plays an important role in maintaining a healthy immune system. When copper levels are low, your white blood cell count may drastically decrease, compromising your ability to combat infection and sickness. This has been found in multiple studies where copper deficiency has dramatically reduced the production of neutrophils – white blood cells which act as the body’s first line of defence.
Memory problems
As the recent study in Scientific Reports highlights, copper plays an important role in brain function and development. Whilst the study states that the relationship between copper and cognitive function is complex and not yet fully understood, the researchers found an association between copper intake and enhanced brain health. This may be a result of copper being used by enzymes to help supply energy to the brain.
It’s entirely possible to consume enough copper from your diet each day, whether you’re a carnivore, vegetarian or vegan, Thornton-Wood says. Here are some of the richest food sources, according to Wilson’s Disease Support Group UK:
Both Aslam and Thornton-Wood agree that – generally – copper supplementation isn’t necessary. “If you have a balanced diet and no underlying medical conditions, you can absorb a good amount of copper without needing any extra supplementation,” Aslam says. “It’s in such a wide range of foods that everyone should be able to get enough copper from their diets, even if they’re vegan or vegetarian,” Thornton-Wood adds.
In a recent preclinical study at the University of Sydney, researchers used a special supplement to restore copper levels in the brains of mice, which helped to reverse Parkinson’s-like symptoms by repairing a key protective enzyme.
While on the surface, this presents a strong argument for taking copper supplements for the possible cognitive benefits, Aslam urges caution. “This research doesn’t mean people should take copper supplements,” she says, “as the treatment used was a targeted drug, not regular copper, and it hasn’t been tested in humans yet.”
If someone has a diagnosed deficiency, is a gastric bypass patient, or has IBD, then a doctor “would do the necessary testing to find out their copper levels, rather than just blindly recommending supplementation”, Aslam says.
Does copper deficiency cause weight gain?
There’s no direct evidence of copper deficiency leading to weight gain, Aslam says. However, as it leads to significant fatigue, an increased risk of infection and numbness in parts of the body, “people with a copper deficiency may be less inclined or able to exercise and maintain a healthy lifestyle and nutrition, so weight gain may be an indirect impact”.
What blocks copper absorption?
If you consume too much zinc, this can block copper absorption because the two minerals compete for absorption in the gut, Aslam explains. Excessive fibre intake can potentially reduce the absorption of copper too, Thornton-Wood says. “This is because fibre can bind to minerals like copper, making them less available for absorption,” she explains.
Can you consume too much copper?
Consuming too much copper can cause copper toxicity, which can have unpleasant and potentially serious side effects, Aslam says. These include nausea, vomiting, diarrhoea, stomach pain, headaches, tremors and – in more severe cases – liver and kidney damage, as it can accumulate in these organs, she explains.
It’s important to note that it’s very rare to eat toxic amounts of copper through a regular diet.