The Role of Nutritional Status in Immunity of Infants and Young Children

Widespread changes in dietary fat intake have occurred over the past 150 years in most industrialized nations, marked by a decrease in consumption of marine- and plant derived n-3 fatty acids and an increase in consumption of n-6 fatty acids. As intake of n-6 fatty acids has increased, the ratio of dietary n-6n-3 fatty acids has shifted substantially. Inadequate levels of vitamins and minerals in the diet can have significant negative consequences for immune function. Key vitamins evaluated for their roles in immunity include the fat-soluble vitamins A and E and the water-soluble vitamins C, B6, B12, and folate. Of the many minerals with functions in immune cell response, iron, zinc, and selenium have been the primary focus of population-based supplementation studies. Although much insight has been gained in the past decade about how the immune system develops and how dietary factors affect that development, numerous questions remain.