More and more research suggests that the copper in your diet could play a bigger role in brain health than we once believed. A recent study found that older Americans who ate more copper-rich foods did better on memory and concentration tests.
The findings, published in Nature Scientific Reports, looked at people’s diets using detailed food diaries and tested their cognitive function. Those who ate more foods that were high in copper – which include shellfish, dark chocolate and nuts – did better on tests that are used to spot early signs of age-related memory loss and dementia.
But the results aren’t straightforward. People who ate more copper-rich foods were mostly male, white, married and had higher incomes. They were also less likely to smoke or have high blood pressure or diabetes – all factors linked to a lower risk of dementia. People who consumed more copper also had more zinc, iron and selenium in their diets, and consumed more calories overall.
People with higher incomes often have better access to healthy food, medical care, cleaner environments and more education – all of which help protect against memory loss and dementia.
It’s hard to separate the effects of diet from these other advantages, although some research we reviewed suggests that improving nutrition might be especially helpful for people from less privileged backgrounds.
What other research tells us
The current study’s limitations are notable. It captured brain function at only one point in time and relied on participants’ food diaries rather than blood measurements of copper levels.
However, long-term studies support the idea that copper might matter for brain health. One study that tracked people over time found that those who had less copper in their diet showed more pronounced declines in memory and thinking.
More intriguingly, when researchers measured copper levels directly in brain tissue, they discovered that higher concentrations were associated with slower mental deterioration and fewer of the toxic amyloid plaques characteristic of Alzheimer’s disease.
Curiously, brain copper levels bore little relationship to dietary intake, suggesting the body’s processing of this mineral is more complex than simple consumption patterns might indicate.
There’s a good biological explanation for why copper might help protect the brain. This essential metal plays several important roles: it helps prevent brain cell damage via antioxidant effects, with production of the chemicals (neurotransmitters) that let brain cells talk to each other, and helps the brain produce energy, by working via particular enzymes.
Copper deficiency is thought to be relatively uncommon, but it can cause noticeable problems. If someone feels tired and weak and has anaemia that doesn’t improve with iron or vitamin B12 supplements, low copper might be to blame. Other signs can include getting sick more often, losing bone strength, and nerve damage that gets worse over time.
Copper is naturally found in high amounts in foods like beef, offal, shellfish, nuts, seeds and mushrooms. It’s also added to some cereals and found in whole grains and dark chocolate.
People who have had gastric bypass surgery for obesity or have bowel disorders may have trouble absorbing copper – and these conditions themselves could be linked to a higher risk of dementia.
It’s best to be cautious about taking copper supplements without careful thought. They body needs a delicate balance of essential minerals – too much iron or zinc can lower copper levels, while too much copper or iron can cause oxidative stress, which may speed up damage to brain cells.
Gabriele Paoletti/Shutterstock.com
Studies examining mineral supplements in people already diagnosed with Alzheimer’s have shown little benefit.
Paradoxically, people with Alzheimer’s often have higher copper levels in their blood, but key brain areas like the hippocampus – which is vital for memory – often show lower copper levels. This suggests that Alzheimer’s disrupts how the body handles copper, causing it to get trapped in the amyloid plaques that are a hallmark of the disease.
Some researchers suggested that after Alzheimer’s develops, eating less copper and iron and more omega-3 fats from fish and nuts might help, while saturated fats seem to make things worse. However, a lack of copper could actually increase plaque build-up before dementia shows up, highlighting the need for balanced nutrition throughout life.
There seems to be an optimal range of copper for brain function – recent studies suggest 1.22 to 1.65 milligrams a day provides copper’s cognitive benefits without causing harm. This mirrors a broader principle in medicine: for many biological systems, including thyroid hormones, both deficiency and excess can impair brain function.
The human body typically manages these intricate chemical balances with remarkable precision. But disease and ageing can disrupt this equilibrium, potentially setting the stage for cognitive decline years before symptoms emerge. As researchers continue to unravel the relationship between nutrition and brain health, copper’s role serves as a reminder that the path to healthy ageing may be paved with the careful choices we make at every meal.
Get your news from actual experts, straight to your inbox. Sign up to our daily newsletter to receive all The Conversation UK’s latest coverage of news and research, from politics and business to the arts and sciences.
