The effect of childhood malnutrition on externalizing behavior

Purpose of review Childhood externalizing behavior (aggression, hyperactivity, and conduct disorder) has been increasingly viewed as a public health problem because of its etiology and outcome. The association between malnutrition and externalizing behavior has begun to receive attention. This review summarizes recent empirical findings on malnutrition as a risk factor for the development of externalizing behavior, with an emphasis on micronutrient deficiency, and explores brain dysfunction as a possible mechanism. Recent findings Externalizing behavior is associated with both macromalnutrition (e.g. protein) and micromalnutrition (e.g. iron and zinc). Both prenatal and postnatal malnutrition is implicated. The long-term effects of malnutrition on behavior could be reversible. The effects of docosahexaenoic acid/omega-3 long-chain essential fatty acid on externalizing behavior are more mixed. From animal and human findings, it is hypothesized that malnutrition impairs neurocognitive functioning by reducing neurons, alternating neurotransmitter functioning, and increasing neurotoxicity, and that such neurocognitive impairments predispose to externalizing behavior. Summary Different lines of evidence support the view that poor nutrition contributes to the development of child behavior problems. More randomized, controlled trials that manipulate nutritional intake and evaluate behavior in children are needed to evaluate the etiological role of nutrition in externalizing behavior in order to inform intervention and prevention efforts.