(08-10-08) Omega-3 Supplementation in Pregnancy Unrelated to Childhood Cognition at Age 7

Women who consume fatty fish or long-chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFAs) during pregnancy have offspring with improved neurodevelopmental outcomes, ranging from higher mental development scores, better infant sleep patterns, greater visual acuity, improved behaviors and more mature neurological performance. Some long-term studies have explored whether the early signs of higher cognition in infants exposed to plenty of n-3 LC-PUFAs in fetal development carries over to childhood. A maternal n-3 LC-PUFA intervention trial in Norway observed higher cognition and intelligence quotient (IQ) scores in 4-year old children, while in the Netherlands, an observational study reported no effect of n-3 LC-PUFA status at birth and cognitive performance in children of the same age. Higher cognitive performance was reported in a US study of 3-year old children whose mothers had the highest fish consumption.

At the age of 7, children in the Dutch study showed no cognitive advantage related to their n-3 LC-PUFA status at birth. Now, the same Norwegian investigators mentioned above report the effect of maternal n-3 LC-PUFA supplementation in pregnancy on the cognitive assessments of the same children at age 7. Both the Dutch and Norwegian studies used the Kaufman Assessment Battery for Children to evaluate cognition.

In this study, investigators provided cod liver or corn oil to 143 pregnant women from 18 weeks’ gestation until 3 months postpartum. The cod liver oil supplied 1.2 g of docosahexaenoic acid (DHA)/day and 800 mg of eicosapentaenoic acid (EPA)/day (total n-3 LC-PUFAs, 2.5 g/day), while the corn oil provided 4.7 g/day of linoleic acid. Approximately half the children in the cod liver oil group consumed cod liver oil regularly during their preschool years and another 27% had taken it sporadically. Among the corn oil children, 46% took cod liver oil regularly and another 23% took it occasionally.

Results from the Kaufman assessments showed no statistically significant differences between the two groups of children on the composite mental processing assessment (intelligence) and on any of the subscales measured. There were significant associations between maternal phospholipid DHA at 35 weeks’ gestation and the mental composite and sequential processing scores. Both maternal and infant phospholipid EPA and alpha-linolenic acid levels were also associated with sequential processing scores. At 3 months postpartum, breast milk EPA, but not DHA, was significantly related to sequential processing scores. These observations suggest that the cognitive advantage of higher n-3 LC-PUFAs seen at 4 years of age had largely disappeared in the subsequent 3 years.

The researchers suggested two possible explanations. One is a dilution effect by factors such as nutrients, drugs, social stimulation and diseases. This interpretation is consistent with the significant confounding effect of parental education on the relationships between DHA and alpha-linolenic acid in maternal phospholipids and the sequential processing scores. Breastfeeding and length of breastfeeding, which supplies DHA and other LC-PUFAs to the infant, was associated with higher intelligence scores in a Swedish study, findings that were linked to the provision of LC-PUFAs. Alternatively, n-3 LC-PUFA concentrations in fetal development and at birth may ultimately have no effect on cognition in later childhood. There is considerable evidence against the latter possibility. The children of mothers with high fish consumption were reported to have fewer social and learning problems at about the same age. Although this report cannot be attributed solely to DHA, it supports the value of eating plenty of fish during pregnancy, which supplies this important LC-PUFA. There is also comfort in knowing that cognitive function in childhood may benefit from other inputs besides fetal and infant nutrition.


Helland IB, Smith L, Blomen B, Saarem K, Saugstad OD, Drevon CA. Effect of supplementing pregnant and lactating mothers with n-3 very-long-chain fatty acids on children's IQ and body mass index at 7 years of age.

Source: Pediatr 2008;122:e472-e479. [PubMed]

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