The prevalence of cognitive impairment is steadily increasing worldwide, primarily due to the aging of the global population. Cognitive decline is a significant hallmark of all forms of dementia, from mild cognitive impairment to Alzheimer’s disease. Recent estimates indicate that the prevalence of dementia is expected to reach 152.8 million by 2050. This highlights the need to develop appropriate strategies to reduce the risk of cognitive impairment. Dietary supplementation with essential micronutrients, including vitamins and minerals, has recently received considerable attention as a valuable strategy for improving cognitive ability and preventing dementia, especially in the elderly population.
Research has shown that an imbalance of certain micronutrients, such as zinc, selenium, and copper, in the brain can lead to cognitive impairment and the subsequent development of neurodegenerative diseases. Copper is a vital oligoelement necessary for the development and functioning of the nervous system. It helps regulate various physiological processes, including neurotransmitter synthesis, cellular energy production, and antioxidant defense. However, maintaining optimal copper levels is essential for proper brain function, as copper deficiency can induce neurological disorders, and copper overdose can lead to oxidative stress and neurodegeneration.
An observational study of older Americans revealed that higher dietary copper intake is associated with improved cognitive function, especially in individuals with a history of stroke. The study is published in Scientific Reports. The study analyzed data from 2,420 participants in the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014. The NHANES sample is designed to be nationally representative of the US population. Information on dietary copper intake was obtained from two 24-hour dietary recall questionnaires. Several cognitive function assessments were performed to explore participants’ memory and executive abilities.
The study results revealed that participants with the highest dietary copper intake had higher cognitive scores than those with the lowest intake. A gradual increase in cognitive function was observed with increasing copper intake, indicating a positive but nonlinear dose-response relationship. The study estimated optimal reference thresholds for copper intake, which were 1.63 milligrams per day for the DSST, 1.42 milligrams per day for the 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 threshold levels.
However, when copper intake exceeded these thresholds, the association lost statistical significance. These observations indicate that cognitive function does not continue to increase with increasing copper intake beyond a certain level. Subgroup analysis revealed that the positive impact of dietary copper intake on global cognitive function was particularly more pronounced among participants with a history of stroke. The current study observed a more pronounced positive impact of copper intake on global cognitive scores among participants with a history of stroke. Existing evidence also indicates the protective efficacy of copper in reducing stroke risk and attenuating neuronal damage in ischemic stroke.
Copper, as a cofactor for antioxidant enzymes, helps reduce free radical production and prevent oxidative lipid damage in the brain. Copper also helps convert pro-inflammatory macrophages into anti-inflammatory macrophages in the brain, thus preventing neuroinflammation. All of these processes highlight the neuroprotective efficacy of copper, which may also provide cognitive benefits. Copper-mediated cognitive enhancement may also be explained by its effect on the synthesis and release of neurotransmitters. Existing evidence indicates that copper aids the synthesis of acetylcholine, a neurotransmitter involved in learning and memory.
Overall, the study results indicate that an optimal level of copper intake, with an inflection point of approximately 1.22 milligrams per day, can improve cognitive function in older adults, particularly those with a history of stroke. Further randomized controlled trials are needed to confirm these findings.
- Edited by Dr. Gianfrancesco Cormaci, PhD, specialist in Clinical Biochemistry.
Scientific references
Jia W, Zhu K et al. Sci Reports 2025 Aug 1; 15:24334.
Zhong G et al. Curr Neuropharmacol. 2024; 22:1650-71.
Meng Q et al. Am J Geriatr. Psych. 2023; 31:753–763.
