Topical Area: Aging and Chronic Disease, Nutrition Translation. Nutrient-Gene Interactions, Carotenoids and Retinoids (CARIG)
Certain amino acids are precursors for neurotransmitters (such as tyrosine being a precursor for dopamine) or directly act on receptors in the brain (such as glutamate and aspartate), and ultimately influence brain function. This study examines the association between dietary amino acids important for neurotransmission and cognitive function in college students with and without Attention Deficit Hyperactivity Disorder (ADHD).
Methods : Undergraduate students (ADHD n=17; controls n=38; age 18-22) were recruited from a mid-Atlantic university. All participants completed a 3-day food diary and dietary data was entered into the Nutrition Data Systems for Research. Average intake estimates were evaluated for total protein and for the amino acids important for neurotransmission: glutamate, glycine, cysteine, aspartate, tyrosine, and tryptophan. Computerized cognitive testing was administered using CNS Vital Signs® software. The resulting Neurocognitive Index (NCI) was the main outcome of interest as a marker of overall neurocognitive status. Data were analyzed in SPSS. Multivariable linear regression was used to estimate the association between the intake of total protein and amino acids with the NCI. Estimates were adjusted for ADHD status, sex, age, and GPA. The protein model was further adjusted for total energy intake (kcal) and amino acid models were further adjusted for total protein intake.
Results : There were no significant differences in protein intake, amino acid intake, nor in cognitive function between the ADHD and control group, thus, these groups were combined for later analyses. The intake of total protein and of glutamate, glycine, cysteine, tyrosine or tryptophan were not significantly related to NCI. However, aspartate was found to be negatively related to NCI (β= -6.83 (SE=2.18), p=0.003).
In this college population, ADHD was not associated with significant deficiencies in cognitive function. However, intake of aspartate was negatively associated with overall cognitive function within the whole college population. Higher dietary intake of aspartate can be observed in individuals consuming the artificial sweetener aspartame or high amounts of gelatin. Future research is needed to further explore the implications of specific amino acids on cognitive function.
Funding Sources : N/A