In pregnancy, the ratio of Omega-6 to Omega-3 intake affects the neurodevelopment of the fetus

Pregnancy: omega 3 and omega 6 ratio essential for healthy growth of baby's brain

A diet high in Omega-6 and low in Omega-3 during gestation is associated with abnormalities in fetal brain development. Inadequate intake of polyunsaturated fatty acids by the mother, therefore, increases the risk for the unborn child to develop cognitive and behavioral deficiencies.

This is the finding of the EDEN Mother-Child Study, a French study conducted by researchers at INSERM (Institute National de la Santè) in collaboration with the Universities of Nancy and Poiters (France). During the research, the scholars explored the relationship between maternal intake of polyunsaturated fatty acids and neurodevelopment in children, while also taking into consideration the role of breastfeeding.

Several studies confirm the link between Omega-3 and cognitive ability

Omega-3s, in which fish oil is rich, and particularly DHA (docosahexaenoic acid) are essential to ensure proper cell structure, function and communication in the brain but also in the retina. In fact, DHA is one of the basic constituents of the membranes of neurons.

During pregnancy, fatty acids are passed from the mother to the fetus. This is why there has been growing interest in the negative effects of a 'maternal diet high in Omega-6 and low in Omega-3, that is, the typical pattern of many Western diets. According to a study published in Lancet in 2007, children whose mothers had eaten a diet low in fish during pregnancy had a higher risk than children of women who consumed a lot of fish of being limited in the development of verbal intelligence, pro-social potential in motor activities and communication A Spanish research study showed that maternal consumption of 2 to 3 servings of fish per week was associated with high scores by 4-year-old offspring on the McCarthy scale, a test to assess childhood abilities In addition, a British study reported evidence of the association between low blood concentrations of Omega-3 and reduced reading and memory skills, in children aged 7 to 9 years. 

It also highlighted how supplementation with DHA improved these conditions in these. The same study also highlighted how, on the other hand, high Omega-6 concentration was associated with good reading ability, a link that, however, lost statistical significance when children's sex and socioeconomic status were also taken into account in the analysis. All these studies directly or indirectly support the hypothesis of the benefits of Omega-3s in cognitive development. In contrast, the role of Omega-6 remains uncertain.

The ratio of Omega-6 to Omega-3 influences cognitive abilities

During the study, 2002 pregnant women, between 24 and 28 weeks gestation, were recruited from prenatal clinics in the Poiters and Nancy areas. The selected volunteers, all with single pregnancies, did not have diabetes, planned to stay in the area of interest, and were able to write and read French correctly. 

At the beginning of the study, each woman reported on a special questionnaire what foods she had consumed in the last trimester of pregnancy. It was thus possible to calculate the intake of total lipids and the percentages of Omega-3 (including alpha linolenic acid) and Omega-6, (including linoleic acid and arachidonic acid) intake. Analysis of the questionnaires showed that 63% of the mothers had consumed less than two servings of fish per week and that only 54% of their DHA intake was derived from this food. Omega-3 and DHA consumption was significantly higher in women who had breastfed, and in these the ratio of Omega 6 to Omega 3 was lower than in mothers who had not breastfed. 

In contrast, no differences were evident in Omega-6 intake Of the 2002 participants, dietary information was obtained from 1585 women. The study then followed the children of the mothers under study after 2 and 3 years in order to assess their cognitive abilities. This phase of the study included the use of the McArthur Communicative Development Inventory questionnaire to assess communication and language, the Ages and Stages questionnaire to determine a developmental delay, the Peg Moving Task to assess manual skills, the Design Copying test to uncover any integrated sensory dysfunction, and a test to estimate verbal fluency In both breastfed and non-breastfed children, the results showed no correlation between mothers' fatty acid intake and the results of the Design Copying test.

In contrast, the high ratio of Omega-6 to Omega-3 was positively associated with performance on the Peg Moving Task and negatively on the Ages and Stages Questionnaire and the Verbal Fluency Test. In breastfed children, no associations were evident between maternal total fatty acid intake and neurodevelopment, just as Omega-3 intake was not found to be related to the results of any cognitive test.In children who had not been breastfed, maternal consumption of total polyunsaturated fatty acids, Omega-6 and linoleic acid was negatively associated with the results of the Communicative Development Inventory and Ages Stages tests. The ratio of Omega-6 to Omega-3 was also inversely related to the scores on these tests and also showed a significant interaction with Verbal Fluency. Also evident was a strong association between breastfeeding and the ratio of Omega-6 to Omega-3 in the Communicative Development Inventory score, and also with that for the Verbal Fluency assessment 

Breastfeeding can compensate for omega-3 deficiency 

With these findings, the researchers hypothesized that the ratio of maternal Omega-6 to Omega-3 may influence development during fetal life. In any case, breastfed infants might escape the 'negative association with Omega-6 and low Omega-3 concentration because they can get the latter from breast milk. The scientists pointed out that the subjects under study in the research, showed a higher socioeconomic status than the French standards, and that the questionnaires on eating habits did not allow them to accurately assess the intake of fatty acids, particularly Omega-3. For example, DHA intake was found to be 170 and 148 mg per day for mothers who had breastfed and who had not breastfed, respectively. Both rather low values. In spite of the study's limitations, the data obtained promote breastfeeding and push for a limitation of Omega-6 consumption in pregnancy.   

Sources: Bernard JY, De Agostini M, Forhan A, de Lauzon-Guillain B, Charles MA, Heude B; the EDEN Mother-Child Cohort Study Group. "Dietary n6:n3 fatty acid ratio during pregnancy is inversely associated with child neurodevelopment in the EDEN mother-child cohort." J Nutr 2013;143:1481-1488. Hibbeln JR, Davis JM, Steer C, Emmett P, Rogers I, Williams C, Golding J. "Maternal seafood consumption in pregnancy and neurodevelopmental outcomes in childhood (ALSPAC study): an observational cohort study." Lancet. 2007 Feb 17;369(9561):578-85. Paul Montgomery,^* Jennifer R. Burton, Richard P. Sewell, Thees F. Spreckelsen, and Alexandra J. Richardson "Low Blood Long Chain Omega-3 Fatty Acids in UK Children Are Associated with Poor Cognitive Performance and Behavior: A Cross-Sectional Analysis from the DOLAB Study" PLoS One. 2013; 8(6): e66697.