New research reveals copper’s power for brain health. A proper amount of this metal, consumed through diet and/or other supportive therapies, could help older adults stay sharp, especially after a stroke. This appears to be demonstrated by a recent study in Scientific Reports.
Background
Is there an association between dietary copper intake and cognitive function in older adults? That is the question tackled by a recent Chinese observational study, conducted in an older American adult population, which would suggest that higher dietary copper intake might contribute to improved cognitive function, particularly among individuals with a history of stroke.
The opportunity is especially timely given that cardiovascular diseases such as stroke, and especially forms of dementia—from mild cognitive impairment to Alzheimer’s disease—are on the rise worldwide. It is estimated that cases of various forms of dementia could reach 152.8 million by 2050, underscoring the urgent need to invest in strategies that reduce the risk of cognitive decline.
Micronutrient dietary supplementation, including vitamins and minerals, has recently attracted considerable attention as a potential resource to support cognitive abilities and prevent dementia, particularly in older adults. Recent studies seem to suggest that imbalances of certain micronutrients—such as zinc, selenium, and copper—at the brain level could contribute to cognitive decline and the subsequent development of neurodegenerative diseases.
Focus on Copper
Copper is a vital micronutrient required for the development and function of the nervous system and participates in a range of physiological processes, including the synthesis of neurotransmitters, cellular energy production, and antioxidant defense. It also serves as a cofactor for several enzymes involved in regulating brain functions. Disturbances in copper homeostasis have been linked to a number of neurodegenerative diseases, including Wilson’s disease and Alzheimer’s disease.
However, dosing it optimally is essential: indeed cerebral copper deficiency could lead to neurological disturbances, while excess could provoke oxidative stress and neurodegeneration.
The objective of the current study was therefore to examine the nonlinear dose–response association between dietary copper intake and cognitive function in a selected sample of U.S. adults aged 60 years and older, comprising more than 2,400 participants drawn from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014: a nationally representative sample of the American population.
Dietary copper intake information was gathered from two 24-hour dietary recall questionnaires, useful for evaluating multiple aspects of cognitive function, including memory and executive abilities. All participants also completed four cognitive tests, specifically the immediate and delayed verbal learning tests (CERAD-IRT and CERAD-DRT), the Digit Symbol Substitution Test (DSST), and the Animal Fluency Test (AFT), and the various scores obtained were averaged to determine the global cognitive score. In particular, CERAD-IRT and CERAD-DRT were used to assess the ability to acquire new verbal information; the DSST to measure processing speed and executive function; and the AFT to analyze verbal and executive abilities.
The results
Evidence appears to indicate that participants with the highest dietary copper intake also report higher cognitive scores than those with lower intake, displaying a gradual increase in cognitive function as copper intake rises, following a positive but nonlinear dose–response relationship.
The study also estimated optimal intake thresholds for copper, identified at 1.63 milligrams per day for DSST, 1.42 milligrams per day for AFT, and 1.22 milligrams per day for the global cognitive score. The positive association between copper intake and cognitive function was observed when copper intake was below these thresholds; when they were exceeded, the association followed an inverted-L curve, losing statistical significance.
A further notable finding emerged from subgroup analyses: the study appears to show that the positive impact of dietary copper on global cognitive function is particularly effective and markedly greater in participants with a prior history of stroke. Specifically, the increase in the global cognitive Z-score within this group was statistically significant (p for interaction = 0.009).
Conclusion
Existing evidence seems to point to a protective effect of copper in reducing stroke risk and mitigating neural damage in ischemic stroke. This may be because copper, as a cofactor for antioxidant enzymes, helps to reduce free radical production and prevent lipid oxidative damage in the brain.
Furthermore, copper might assist in converting pro-inflammatory macrophages (microglia) in the brain into anti-inflammatory macrophages, thereby preventing neuroinflammation and potentially benefiting cognition through its influence on neurotransmitter synthesis and release.
There is also evidence, for example, of copper’s role in acetylcholine synthesis, a neurotransmitter involved in learning and memory. Overall, the study’s findings suggest that an optimal level of copper intake, with an inflection point around 1.22 milligrams per day, could improve cognitive function in older adults, particularly among those with a history of stroke. Further randomized controlled trials will be needed to confirm these results, as the cross-sectional design of the current study cannot establish causality. Residual confounding from unmeasured dietary or lifestyle factors could also influence the findings.
Source
Jia W, Zhu K, Shi J et al. Association between dietary copper intake and cognitive function in American older adults: NHANES 2011–2014. Scientific Reports, 2025, 15, Article number: 24334. Link: https://www.nature.com/articles/s41598-025-09280-9
Abbonati a Karla Miller
