Investigating the relationship between select dietary elements and cognitive functioning in Gulf War veterans
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Abstract
BACKGROUND: Gulf War Illness (GWI) is a chronic multisymptom condition that affects approximately one-third of all 1990-1991 Gulf War (GW) veterans and is characterized by debilitating fatigue, chronic pain and cognitive difficulties. Cognitive decrements are some of the most common and distressing symptoms of the disorder. Although multiple studies have investigated cognitive outcomes in GWI, little is known about the relationship between dietary elements and cognitive functioning in GW veterans.
AIMS: The study aims were to investigate the relationship between select dietary elements (zinc, magnesium, and manganese) and a cognitive test battery (including attention/executive functioning, learning & memory, and mood) in GW veterans.
METHODS: Urine samples and cognitive test battery data from 187 participants of the Boston Biorepository, Recruitment, and Integrated Network (BBRAIN) study for GWI were compared in this study. Urine samples were used to assess zinc, magnesium, and manganese levels. The Conners Continuous Performance Test Third Edition (CPT3) and the Delis–Kaplan Executive Function System Color-Word Interference Test (CWIT) were used to assess for attention and executive functioning, specifically sustained attention and interference inhibition. The California Verbal Learning Test – Second Edition (CVLT-II) and the Rey-Osterrieth Complex Figure Test (ROCFT) scores were used to assess verbal and visual memory. Lastly, the Profile of Mood States (POMS) and Center for Epidemiologic Studies Depression Scale (CESD) questionnaires were used to assess for both elevated mood complaints and depression. To assess the potential relationships between the selected dietary element levels and the cognitive outcomes of interest, the 187 GW veterans were stratified into quartiles based on their element concentrations. Histograms, box plots, generalized linear models, and the stargazer function in R Studio were used to visualize and analyze the data.
RESULTS: All analyses referenced the first (lowest) concentration quartile. In assessing executive attention and function, the CPT3 results most significantly indicate an association between higher levels of Mn and potential impulsivity. For the CWIT, Zn was associated with a marginal increase in trial times, Mg was associated with a marginal decrease in trial times but significant decrease in uncorrected errors, and the highest levels of Mn were associated with an increase in trial times. For learning and memory, the CVLT-II trials 1-5 showed marginal associations between the highest quartile of Zn and the second quartile for Mg and an increase in the number of words learned and recalled, while the highest quartile of Mn was associated with a decrease in the number of words learned and recalled. For mood, on the POMS questionnaire, the fourth quartile for Mg was associated with a marginal decreased Fatigue-Inertia scale scores and the second quartile for Mn was associated with a marginal decrease in Depression-Dejection scale scores. Associations were not found between the dietary elements and the ROCFT and CESD questionnaire.
CONCLUSION: The relationship between cognitive functioning and select dietary elements (zinc, magnesium, and manganese) indicate more positive cognitive outcomes with higher levels of Zn and Mg, and lower levels of Mn. The results suggest that dietary changes or supplementation could have some potential as therapeutic targets for GW veterans’ cognitive decrements upon further investigation and validation. Key words: Gulf War Illness, Veterans’ health, cognition, elements
Description
2025
License
Attribution 4.0 International