The results of a new study suggest that it is not just the tissue levels of DHA that are important in cognitive development of children aged 7 to 12 years, but that the omega-6/omega-3 ratio is also important (1)

By Rob Winwood

Marine-derived, long chain, omega-3 fatty acids are widely believed to play an important role in cognitive performance throughout all life stages. Docosahexaenoic acid (DHA) is the dominant omega-3 fatty acid in the brain and a major component of neuronal cell membranes. DHA is important for the efficacy of neurological pathways and processes. A recent review of current scientific evidence suggests that consumption of DHA may enhance cognitive performance relating to learning, cognitive development and the speed of performing cognitive tasks in children and throughout adulthood (2). The DOLAB (DHA Oxford Learning and Behaviour) study demonstrated that an intervention of 600 mg algal DHA/day for 16 weeks in 493 healthy British children, aged 7 to 9 years (but who were underperforming in reading) improved reading ability and parent-rated behavior of the lower quintile (3).

A new study suggests that it is not just the tissue levels of DHA that are important in cognitive development, but that the omega-6/omega-3 ratio is also important (1). The study applied a battery of cognitive tests to 78 American children divided into two age ranges, 7 to 9 years old and 10 to 12 years old. Their dietary intake and tissue levels of DHA were also determined. The results demonstrated that both an optimal omega-6/omega-3 balance (10:1 or less) and a high DHA tissue level were required for optimal cognitive development.  Interestingly, the two age groups differed, with the omega-6/omega-3 ratio being more important for the younger children, while total tissue DHA levels were important for the older children. This may be because the onset of puberty brings about increased accretion of DHA in the hippocampus and frontal cortex, both of which are associated with high-level decision making.

1. Sheppard KW & Cheatham CL; “Executive functions and the n-6 to n-3 fatty acid ratio : a cross-sectional study”; AJCN 2016;  http://doi.org/10.3945/ajcn.116.141390.
2. Stonehouse W; “Does Consumption of LC Omega-3 PUFA Enhance Cognitive Performance in Healthy School-Aged Children and throughout Adulthood? Evidence from Clinical Trials”; Nutrients 2014, 6, 2730-2758; doi:10.3390/nu6072730
3. Montgomery P, Burton JR, Sewell RP et al.; “Low Blood Long Chain Omega-3 Fatty Acids in UK Children Are Associated with Poor Cognitive Performance and Behaviour: A Cross-Sectional Analysis from the DOLAB Study.”; PLoS ONE 2013; 8(6): e66697. doi:10.1371/journal.pone.0066697