Micronutrient Status and its Effect on Infant Neurocognitive Development

Abstract

Micronutrient deficiencies can significantly impair cognitive development, especially during critical periods in early infant life. As well, micronutrient levels that are not explicitly deficient, but at sub-clinical levels, might confer developmental risk. The present thesis aims to assess severity of thiamine, iron, and vitamin A deficiency in a sample of infants participating in a randomized control trial (RCT) in rural Cambodia (Whitfield et al., 2019), and examine possible relationships of such deficiency to infants’ neuro-cognitive development. Data were collected in Kampong Thom, Cambodia from exclusively breastfed infants (n=335) participating in a four-arm RCT; mothers were supplemented with thiamine (0, 1.2, 2.4, 10 mg/day dosage levels) across the first 6 months postpartum. Infant blood at 24 weeks was assayed for a) erythrocyte transketolase activity coefficient (ETKac) for thiamine, b) ferritin for iron, and c) retinol binding protein (RBP) for vitamin A. Neurocognition was assessed at 24 and 52 weeks via the Mullen Scales of Early Learning (MSEL). We found that infants were at higher risk for vitamin A deficiency compared to thiamine and iron (though the risk of thiamine deficiency was higher in the placebo group compared to the other supplementation groups). In addition, thiamine (ETKac) and MSEL baseline scores were significantly associated with MSEL motor and language scores at 24 and 52 weeks. However, the directionality of relationship between ETKac and MSEL scores was opposite of our expectations, which is consistent with the hypothesis that early life lack of access to adequate thiamine reduces infant ETK production. In summary, these findings underscore that infants in rural Cambodia face the risk of multiple micronutrient deficiencies and these deficiencies – even at marginal levels – can be associated with negative consequences for their neuro-cognitive development. These findings will contribute in important ways to designing nutritional interventions to protect infants’ neurocognitive outcomes.