The dietary requirements for essential fatty acids and the possibility of a specific role for the polyunsaturated fatty acid docosahexaenoic acid (DHA) is one of the most controversial areas in infant nutrition.

DHA is found in unusually high concentrations in the brain and is selectively accumulated during fetal and infant brain growth. DHA can be synthesised through a complex series of chain elongation-desaturation reactions from alpha-linolenic acid, but the efficiency of this process in young infants is not clear.

Clinical studies on the potential benefits to neural development of dietary DHA have yielded conflicting results. Recent studies have provided evidence that plasma DHA is available to developing brain and that DHA is involved in dopamine and serotonin metabolism.

These findings should guide clinical studies to more sensitive measures of the functional roles of dietary n-3 fatty acids and to clinical conditions where n-3 fatty acids may have benefit.