Magnesium Intake, Sociodemographic Determinants, and Memory Performance in Older Adults: A Sex-Stratified Analysis in NHANES 2011–2014

Background: Magnesium intake (MgI) has been associated with cognitive health in older adults, but the influence of sex, socioeconomic factors, and overall dietary intake remains unclear. Methods: We analyzed adults aged ≥ 60 years from the National Health and Nutrition Examination Survey (NHANES) 2011–2014. Of 3079 participants eligible before missing data exclusions, 2397 (1153 men and 1244 women) then had complete information for the final structural equation model (SEM). Total magnesium intake included dietary and supplemental sources assessed using two 24-h dietary recalls. Memory performance was derived using principal-component factor analysis of CERAD word-recall and animal-fluency assessments. Survey-weighted, sex-specific SEMs evaluated associations among magnesium intake, memory performance, age, education, household income, and total energy intake. Results: Participants had a mean age of 70 ± 6.8 years, 52% were female, and mean BMI was 29 ± 6.4 kg/m2. Without energy adjustment, total magnesium intake showed a positive but nonsignificant association with memory in men (β = 0.043, p = 0.387) and women (β = 0.080, p = 0.105). After energy adjustment, the associations were attenuated in men (β = 0.030, p = 0.486) and women (β = 0.040, p = 0.532). Energy intake was strongly associated with magnesium intake but not with memory. Education was positively associated with memory, whereas age was negatively associated in both sexes. Conclusion: Total magnesium intake was not independently associated with memory performance after accounting for energy intake and sociodemographic factors. Education and age remained the most consistent predictors of memory. These findings highlight the importance of considering overall dietary intake when examining nutrient–cognition relationships.