There’s no doubt that omega-3 DHA is absolutely essential to brain and eye development … and to key functions in both organs, throughout out life.
And most studies link higher maternal DHA intakes to slightly better brain and eye function in infants and toddlers.
For too long, it remained unclear how long kids of fish-loving mothers could continue to benefit from getting ample amounts of DHA during pregnancy and nursing.
In that study, kids of fish-loving moms scored higher on tests measuring fine motor, communication, and social skills, showed better social behaviors, and were less likely to have low verbal IQ scores.
Now, a joint US-Canada team has just published a smaller study in Inuit (Eskimo) children, tying higher umbilical intake of DHA from mothers to better memory performance through age 13.
This encouraging finding follows hard on the heels of a study in the same Inuit communities, which showed better visual performance through age 11 in kids who got more DHA in the womb (Jacques C et al. 2011).
Memory gains added to likely benefits of mom-provided omega-3 DHA
The new study was led by Joseph L. Jacobson, PhD of Michigan’s Wayne State University School of Medicine, and involved 154 children (Boucher O et al. 2011).
Blood samples had been collected from the kids’ umbilical cords at birth, to provide a good picture of their intakes of omega-3 DHA, mercury, and PCBs.
Between 2005 and 2007 – when the kids were aged 10 to 13 – they took part in tests commonly used to measure the accuracy of visual and verbal memory in school-age children.
The authors’ analyses revealed that the children with higher levels of omega-3 DHA scored higher on tests of visual and verbal memory.
Brain gains not blunted by relatively high levels of mercury at birth
Importantly, as the US-Canada team reported, even the presence of relatively high levels of mercury and PCBs in babies’ cord blood didn’t blunt the size of the memory benefits seen 10 to 13 years later: “DHA–related effects [benefits] were observed regardless of seafood-contaminant amounts.” (Boucher O et al. 2011)
The Inuit kids’ cord blood mercury levels were 20 times higher than those seen in southern
Quebec which would be similar to the average U.S. baby’s cord blood mercury levels.
And levels of PCBs in the Inuit babies’ cord blood were three times higher than in southern Quebec and the U.S.
The high mercury and PCB levels flow from the fact that the Inuit eat a great deal of seafood and marine mammal (whale/seal) meat.
On average, the children in the study ate about one marine mammal meal and 1.5 fish meals per week, which was about one-half the large amount consumed by Inuit women during pregnancy.
Why the mercury in seafood is safe
We offer only seafood that’s naturally low in mercury... however, the evidence virtually proves that this policy is not essential to ensure safety.
Instead, most seafood is safe for children and adults to consume as frequently as desired… and the evidence demonstrates this in a compelling fashion.
In short, the varying – but almost entirely positive – outcomes of studies that examine the impact of seafood on child development are explained by the interactions between selenium and mercury in people’s bodies.
As long as the body has enough “available” selenium (i.e., not bound to mercury), it suffers no harm from even relatively high levels of mercury.
Almost all ocean fish contain substantially more selenium than mercury. (Fresh water fish can be very high in mercury and very low in selenium, depending on where they are caught. Consult local advisories on lake and river fish.)
In contrast, marine mammals contain significantly more mercury than selenium, and high levels of PCBs.
The criminally ignored, scientifically compelling research explains why the evidence supports the safety of eating ample amounts of seafood at any age, and during pregnancy and nursing.
Boucher O, Burden MJ, Muckle G, Saint-Amour D, Ayotte P, Dewailly E, Nelson CA, Jacobson SW, Jacobson JL. Neurophysiologic and neurobehavioral evidence of beneficial effects of prenatal omega-3 fatty acid intake on memory function at school age. Am J Clin Nutr. 2011 May;93(5):1025-37. Epub 2011 Mar 9.
Cohen JT, Bellinger DC, Connor WE, Shaywitz BA. A quantitative analysis of prenatal intake of n-3 polyunsaturated fatty acids and cognitive development. Am J Prev Med. 2005 Nov;29(4):366-74.
Jacobson JL, Jacobson SW, Muckle G, Kaplan-Estrin M, Ayotte P, Dewailly E. Beneficial effects of a polyunsaturated fatty acid on infant development: evidence from the inuit of arctic Quebec. J Pediatr. 2008;152:356–364
Jacques C, Levy E, Muckle G, Jacobson SW, Bastien C, Dewailly E, Ayotte P, Jacobson JL, Saint-Amour D. Long-term effects of prenatal omega-3 fatty acid intake on visual function in school-age children. J Pediatr. 2011 Jan;158(1):83-90, 90.e1. Epub 2010 Aug 25.
Schuchardt JP, Huss M, Stauss-Grabo M, Hahn A. Significance of long-chain polyunsaturated fatty acids (PUFAs) for the development and behaviour of children. Eur J Pediatr. 2010 Feb;169(2):149-64. Epub 2009 Aug 12. Review.