Walnuts, Long-Chain Polyunsaturated Fatty Acids and Adolescent Brain Development

Background: Adolescence is an important period for brain development as a result of increased synaptic plasticity. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) are essential nutrients for brain development and protection against oxidative stress. Walnuts have the highest n-3 PUFA concentrations of all edible plants. Objective: The investigators hypothesize that walnut intake will increase n-3 PUFA availability in the body to a level that enhances the development of the brain during adolescence. The technicians will conduct a long-term (6 months) population-based randomized controlled trial in teenagers (n=400 in each arm), and determine the effectiveness of the intervention (30 g of walnut kernels per day, \~1.5g of n-3 PUFA) in enhancing brain development. Methods: Fieldwork team will contact teenagers and families in collaboration with 20 high schools. Families will receive a basic guide on following a healthy diet in order to ensure implementation and adherence. Brain development outcomes will be measured at baseline and after the intervention. The use of computerized neuropsychological tests will provide the precision required to detect even subtle changes in brain development resulting from the nutritional intervention. Behavioral (socio-emotional) development will be assessed in order to cover a wider picture of brain development. Blood samples will be collected to measure n-3 PUFA levels before and after the intervention in a randomized subsample from both groups (control/ intervention). Linear regression models adjusted for baseline neuropsychological scores will be used to analyze the intervention effect. Implications: The outcomes of this Project are expected to be a greater understanding of the role of n-3 PUFA intake (walnut) in brain development. A major goal in public health research is to develop cost-effective health recommendations to teenagers.