Association Between Mineral Intake and Cognitive Performance in Spanish Adults with Overweight and Obesity: A Cross-Sectional Study

Background/Objectives: While adequate mineral intake is essential for brain health and cognitive function across the lifespan, the potential impact of excessive consumption remains underexplored. This study aimed to examine the association between dietary intake of selected minerals, with particular focus on iron and zinc, and cognitive performance in Spanish adults with obesity, particularly in executive-related domains such as reasoning, cognitive flexibility, and working memory. Methods: A cross-sectional study was conducted in 230 Spanish adults (18–65 years) from the Tech4Diet-Person project. Sociodemographic, dietary, and cognitive data were collected between 2021 and 2024. Cognitive function was assessed using the validated computerized CogniFit battery, and mineral intake was estimated through a food frequency questionnaire (93 items). Individuals with neurological, metabolic, or psychiatric disorders, as well as pregnant or lactating women, were excluded. Results: Participants had a mean age of 45.91 (±9.92) years. Nominal differences in mineral intake were observed across specific executive cognitive domains. Higher dietary iron intake was associated with lower performance in reasoning and cognitive flexibility, while higher zinc intake was associated with lower working memory performance. In adjusted logistic regression models, higher iron intake was independently associated with increased odds of low reasoning performance (OR = 1.25; p = 0.006), and higher zinc intake was associated with increased odds of low working memory performance (OR = 1.36; p = 0.024), after controlling for age, educational level, BMI, and total energy intake. Conclusions: Higher self-reported intake of iron and zinc showed nominal associations with lower performance in specific executive domains. These findings should be considered exploratory and require confirmation in longitudinal and biomarker-based studies.