Higher Copper Consumption Linked to Enhanced Cognitive Function in Seniors

Cognitive decline is becoming more prevalent worldwide, with all stages of dementia characterized by reduced memory and executive function. Previous investigations have explored whether micronutrient levels might influence cognitive resilience.

Copper is a vital trace mineral that plays roles in neuronal energy metabolism, neurotransmitter production, and antioxidant regulation. Past studies have suggested both beneficial and detrimental effects of copper on neurodegenerative diseases, contingent upon its bioavailability and concentration within neural tissues.

The study "Association between dietary copper intake and cognitive function in older American adults," published in Scientific Reports, aimed to analyze the relationship between dietary copper consumption and cognitive performance through a cross-sectional assessment.

A cohort of 2,420 participants aged 60 or above was drawn from the 2011–2014 National Health and Nutrition Examination Survey (NHANES). All participants had complete dietary intake and cognitive function data.

Dietary copper intake was assessed using two averaged 24-hour dietary recalls. Cognitive function evaluations included the Digit Symbol Substitution Test (DSST), the Animal Fluency Test (AFT), immediate and delayed recall subtests of the CERAD protocol, and a composite Z score representing overall cognitive performance. Copper intake was categorized into quartiles.

Multivariate linear regression models were employed to test these associations. The fully adjusted model revealed that participants in the highest copper intake quartile (Q4, ≥1.44 mg/day) scored higher than those in the lowest quartile (Q1, <0.76 mg/day): DSST (β=3.80, 95% CI 1.90, 5.70), AFT (β=1.23, 95% CI 0.48, 1.99), CERAD-DRT (β=0.47, 95% CI 0.15, 0.80), and Z score (β=0.20, 95% CI 0.10, 0.29). There was no statistically significant link with CERAD-IRT in the fully adjusted model (β=0.58, 95% CI −0.06, 1.22).

Participants in higher copper intake quartiles were more likely to be male, non-Hispanic white, married, and have higher income, with less smoking prevalence and better nutritional profiles, including increased intake of zinc, iron, selenium, and total energy.

Spline-based regression modeling indicated an inverted L-shaped relationship between copper intake and DSST, AFT, and Z score. Cognitive performance improved with copper intake up to thresholds of 1.63 mg/day (DSST), 1.42 mg/day (AFT), and 1.22 mg/day (Z score).

Beyond these thresholds, associations with DSST, AFT, and Z score lost statistical significance, showing near zero change and wide confidence intervals.

Individuals with a history of stroke exhibited a stronger link between copper intake and global cognition. In this subgroup, Q4 intake was associated with a higher Z score than Q1 (β=0.55, 95% CI 0.24, 0.86; p for interaction=0.009). No significant interaction effects were observed for other demographic or clinical variables.

Study authors conclude that increased copper intake is associated with better cognitive test scores in older adults, with the strongest associations at moderate levels of intake and most pronounced effects found in those with a prior stroke.

While the exact mechanisms behind the relationship between dietary copper intake and cognitive function remain unclear, the authors suggest "… these findings are biologically plausible. Dietary copper is essential for brain health and may provide protective benefits to cognitive function through its role in antioxidant defense, neurotransmitter synthesis, and energy metabolism."

Written by our author Justin Jackson, edited by Sadie Harley, fact-checked and reviewed by Andrew Zinin—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you.