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New research uncovers the brain-boosting power of copper; just the right amount could help older adults stay sharp, especially after a stroke.

Study: Association between dietary copper intake and cognitive function in American older adults: NHANES 2011–2014. Image credit: Danijela Maksimovic/Shutterstock.com

An observational study involving American older adults revealed that higher dietary copper intake is associated with higher cognitive function, especially in individuals with a history of stroke. The study is published in Scientific Reports.

Background

The prevalence of cognitive impairment is steadily increasing worldwide, mainly due to the increasing global aging population. Cognitive decline is a significant sign of all forms of dementia, ranging 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 for developing appropriate strategies to reduce the risk of cognitive impairment.

Dietary supplementation with essential micronutrients, including vitamins and minerals, has recently gained considerable attention as a valuable strategy to improve cognition and prevent dementia, especially in the older population. Research has shown that the 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 micronutrient required for the development and functioning of the nervous system. However, an optimal level of copper should be maintained for proper brain functioning, as its deficiency can induce neurological disorders, and its overdose can lead to oxidative stress and neurodegeneration.

In the current study, researchers investigated the non-linear, dose-response association between dietary copper intake and cognitive function in American adults aged 60 years or above.

The study

The study analyzed data of 2420 participants from the 2011 to 2014 National Health and Nutrition Examination Survey (NHANES). The NHANES sample is designed to be nationally representative of the U.S. population.

The information on dietary copper intake was derived from two 24-hour dietary recall questionnaires. Several cognitive function assessments were carried out to explore participants’ memory and executive abilities.

In the NHANES study, participants underwent four cognitive function tests, including the immediate and delayed verbal list learning tests (CERAD-IRT and CERAD-DRT), the Digit Symbol Substitution Test (DSST), and the Animal Fluency Test (AFT). The scores of all these tests were averaged to determine the global cognitive score.  

CERAD-IRT and CERAD-DRT were used to assess the capacity for novel linguistic acquisition; DSST was used to measure processing speed and executive function; and AFT was used to measure verbal and executive abilities.

Key findings

The study findings revealed that participants with the highest dietary copper intake have higher cognitive scores than those with the lowest copper intake. A gradual increase in cognitive function was observed with increasing copper intake, indicating a positive but non-linear 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 the copper intake was lower than these threshold levels. However, when the copper intake exceeded these thresholds, the association followed an inverted L-shaped curve and lost statistical significance. These observations indicate that cognitive function does not continue to increase with increasing copper intake after a certain level.

The subgroup analysis revealed that the positive impact of dietary copper intake on global cognitive function is particularly more pronounced among participants with a history of stroke.  Specifically, the increase in the global cognitive Z score in this group was statistically significant (p for interaction = 0.009).

Study significance

The study highlights the importance of dietary copper intake in improving cognitive functions in older adults, especially those with a history of stroke.

Copper is a vital micronutrient that helps regulate various physiological processes, including neurotransmitter synthesis, cellular energy production, and antioxidant defense. It also acts as a cofactor for several enzymes associated with brain function regulation.

Impaired copper homeostasis has been linked to a range of neurodegenerative diseases, including Wilson’s disease and Alzheimer’s disease.

The current study observed a more prominent positive impact of copper intake on the global cognitive score 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 to anti-inflammatory macrophages in the brain, leading to the prevention of neuroinflammation. All these processes highlight the neuroprotective efficacy of copper, which may also ensure cognitive benefits.

Copper-mediated cognitive improvement can also be explained through its effect on neurotransmitter synthesis and release. Existing evidence indicates that copper is crucial in synthesizing acetylcholine, a neurotransmitter involved in learning and memory.

Overall, the study findings indicate that an optimal level of copper intake, with an inflection point of approximately 1.22 milligrams per day, may improve cognitive function in older adults, especially those with a history of stroke. Further randomized controlled trials are necessary to confirm these findings.

However, causal relationships cannot be established due to the study’s cross-sectional design. Residual confounding from unmeasured dietary or lifestyle factors may also influence the results.

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Three cases of Nipah virus infection have been reported in Malappuram and Palakkad district in Kerala in 2025 and 677 contacts have been traced, Minister of State for Health Prataprao Jadhav told the Lok Sabha on Friday. Control measures have been initiated and steps have been taken by the government to contain Nipah outbreaks, Jadhav said in a written reply. The infection is an emerging zoonotic infectious disease caused by Nipah virus (NiV). It mainly affects pigs and humans. Nipah cases in humans tend to occur in a cluster or as an outbreak, especially among close contacts and caregivers, Jadhav explained. The natural host of the virus is believed to be Pteropid fruit bats (flying foxes). According to the information available fruit bats play a significant role in the transmission of this disease. The minister said the NiV infection closely follows the spill over of pathogen from fruit bats to intermediate hosts or human beings. In India, the majority of the infections coincide with palm date sap collection times. Due to this, Nipah cases occurs again and again at some areas, Jadhav said. Listing the control measures initiated to contain Nipah disease outbreaks, Jadhav said that through surveillance mechanism early warning signals are captured to generate alerts, outbreaks in the early rising phase are detected and outbreak investigations are conducted and timely appropriate measures are undertaken by the respective public health agencies to control and prevent the further spread of the disease. A National Joint Outbreak Response Team (NJORT), comprising of experts from Department of Animal Husbandry and Dairying, Forest and Wildlife and human health, and bat survey team are deployed for comprehensive assessment and review of these outbreaks. Malappuram and Palakkad, with Kozhikode, Thrissur, and Wayanad districts were placed on alert. Whole genome sequencing was performed on clinical specimens from all positive cases, Jadhav said. This genomic surveillance aids in understanding the circulating Nipah virus strain, which belong to similar genotypes of 2019 and 2021 outbreaks in Kerala, he informed. Beyond the immediate outbreak response, Ministry of Health and Family Welfare (MoHFW) maintained continued support and collaborative engagement with both Virus Research and Diagnostic Laboratories (VRDLs) throughout the year, ensuring training, a steady supply of personal protective equipment (PPE) and diagnostic reagents. This sustained effort underscores a commitment to strengthening regional capacities for infectious disease preparedness and response, Jadhav stated. He said the state and central government health officials worked to enhance public and healthcare professional awareness regarding Nipah virus disease. These initiatives ensured that individuals were made aware on the signs and symptoms of the disease and understood the appropriate actions to take if they suspected an infection in themselves or others, the minister added. Integrated Disease Surveillance Programme (IDSP) under the MoHFW mandates surveillance and response to outbreak prone communicable diseases. The IDSP is implemented in all 36 states and Union territories, Jadhav said. The programme is responsible for the surveillance of 50 plus epidemic prone diseases and outbreak investigation and plays a crucial role in prompt response and surveillance of emerging and re-emerging diseases, including Nipah virus disease in the country. The Indian Council of Medical Research (ICMR) and ICMR-National Institute of Virology (NIV), Pune, have strengthened Nipah surveillance by enhancing Acute Encephalitis Syndrome (AES) in Kerala and Severe Acute Respiratory Illness (SARI) surveillance in West Bengal and Kerala since October-November 2024, he said. A comprehensive guideline on Nipah virus has been prepared, and under National One Health Programme for Prevention and Control of Zoonotic Diseases (NOHP-PCZ), various initiatives are taken to strengthen prevention, detection, and response capacities for zoonotic diseases in India, including NiV. Zoonosis committee have been formed in all states and UTs to review status of all zoonotic diseases, including Nipah virus, Jadhav stated.

Nutrition assistance programs do more than fighting hunger. They also may help guard against age-related cognitive decline.

Researchers found that people who participated in the US Supplemental Nutrition Assistance Program (SNAP) had slower cognitive decline over 10 years than peers who did not participate in the program.

“The chief policy implication of our study is that nutrition assistance programs like SNAP are not just anti-hunger tools — they are also public health tools that may help protect cognitive function and promote healthy aging,” lead author Linlin Da, MPH, PhD candidate, University of Georgia College of Public Health, Athens, Georgia, told Medscape Medical News.

The study was presented on July 30 at the Alzheimer’s Association International Conference (AAIC) 2025.

Healthy Food, Healthy Brain 

Using the nationally representative Health and Retirement Study, researchers analyzed a racially and ethnically representative group of people aged 50 years or older. 

They compared 1131 individuals (mean age, 63 years) who were enrolled in SNAP in 2010 to 1216 individuals (mean age, 66 years) who were eligible for SNAP but did not participate in the program.

“Our study focused on SNAP — a real-world, policy-level intervention — rather than just individual food choices,” Da noted.

As part of the study, memory and executive function were assessed every 2 years between 2010 and 2020 via telephone or web-based interviews. Individuals with an initial cognition summary score indicating cognitive impairment or dementia were excluded from the analysis.

The researchers found that SNAP participants had a 0.10% slower decline in overall cognitive function (P < .001), or 2-3 additional years of cognitive health over the 10-year period.

“For someone starting at a healthy cognitive score, this slower decline could delay reaching the threshold for mild cognitive impairment by nearly a decade,” Da noted in a conference statement.

SNAP participants also had a slower decline in memory (P < .001) and executive function (P = .004) than peers not enrolled in SNAP.

“Our study is one of the first long-term, nationally representative studies to show that participation in a federal nutrition assistance program like SNAP is associated with slower cognitive decline in older adults,” Da told Medscape Medical News.

Da said there are several biological and social mechanisms that may explain how SNAP participation slows cognitive decline, including improved nutrition.

“SNAP increases access to nutrient-dense foods that support brain health — such as fruits, vegetables, whole grains, and lean proteins. Better nutrition is linked to reduced inflammation, improved vascular health, and preservation of cognitive function over time,” Da explained.

Reduced food insecurity and stress is another possibility. “Chronic food insecurity is a significant source of psychological stress, which can negatively impact brain function. SNAP helps alleviate financial and emotional strain, leading to lower levels of chronic stress and potentially reducing harmful stress-related effects on memory and executive function,” Da said.

“We hope healthcare providers will see that potentially delaying cognitive impairment is another reason to help their patients-in-need secure access to food assistance,” co-author Suhang Song, PhD, assistant professor, Department of Health Policy and Management, 

University of Georgia College of Public Health, added in a conference statement.

Equity Gaps

While all racial and ethnic groups benefitted from SNAP participation, the protective effects on cognitive decline were smaller among non-Hispanic Black and Hispanic older adults compared with non-Hispanic White participants.

There were “racial and ethnic disparities in the cognitive benefits of SNAP, which points to important equity gaps in how nutrition policies may impact different populations,” Da said.

“We guess, even with SNAP, living in food deserts or areas with fewer healthy food options may limit the quality of nutrition people can access. This can especially affect Black and Hispanic communities, where structural barriers to healthy eating persist,” Da said.

Commenting on this study for Medscape Medical News, Courtney Kloske, PhD, director of Scientific Engagement for the Alzheimer’s  Association, said it “highlights the importance of nutritious foods and the impact that can have on the brain.”

Maria Carrillo, PhD, chief science officer and medical affairs lead, Alzheimer’s Association, noted that food insecurity can negatively affect cognitive function, and this is one of the first long-term studies to show that food assistance programs can positively impact cognition.

“Simple, everyday actions can make a difference in brain health and may even lower the risk of Alzheimer’s disease and dementia. The Alzheimer’s Association is committed to helping all people build these habits into their daily lives, including eating right, one of our 10 Healthy Habits for Your Brain,” Carrillo said in a statement.

The authors, Kloske and Carrillo, reported no disclosures.