This review is part of a series intended for non specialists that will summarise evidence relevant to the question of whether causal relations exist between micronutrient deficiencies and brain function. Here, we focus on experiments that used cognitive or behavioural tests as outcome measures in experimental designs that were known to or were likely to result in altered brain concentrations of the n–3 fatty acid docosahexaenoic acid (DHA) during the perinatal period of “brain growth spurt.” Experimental designs reviewed include observational breastfeeding studies and randomised controlled trials in humans and studies in rodents and nonhuman primates. This review is based on a large number of expert reviews and commentaries and on some 50 recent studies in humans and animals that have not yet been included in published reviews. Expert opinion regarding the strengths and weaknesses of the major experimental systems and uncertainties associated with interpreting results is summarised. On the basis of our reading of this literature, we conclude that evidence from several types of studies, particularly studies in animals, suggests that, within the context of specific experimental designs, changes in brain concentrations of DHA are positively associated with changes in cognitive or behavioural performance. Additional experimental information required to conclude that a causal association exists is discussed, as are uncertainties associated with applying results from specific experimental designs to the question of whether infant formula should be supplemented with DHA.
McCann JC, Ames BN. Is docosahexaenoic acid, an n-3 long-chain polyunsaturated fatty acid, required for development of normal brain function? An overview of evidence from cognitive and behavioural tests in humans and animals. Am J Clin Nutr. 2005 Aug;82(2):281-95. View Abstract View Full Paper