Adding fatty acids to infant formula associated with slightly worse cognition at the age of nine

Adding omega-3 and omega-6 fatty acids to infant formula improves baby development during the first three months of their lives. But by the age of 9 years, these children’s brains appear to function somewhat less well than those of children fed formula without extra fatty acids. They are slightly worse in planning and organization, have a smaller vocabulary and have acquired less knowledge. These are among the findings of research carried out by Mijna Hadders-Algra, Professor of Developmental Neurology in the University Medical Center Groningen, into the long-term effects of these supplements. She and her research group just published their results in the scientific magazine Developmental Medicine & Child Neurology.

It has been known for some time that breast-fed children have a slightly higher IQ than bottle-fed children. Hadders’ study adds more weight to the adage ‘Breast is best’. The fact that mothers who breast feed are on the whole better educated than mothers who decide to bottle-feed their infants is a possible explanation, but the composition of the milk itself could also play a role. Breast milk contains omega-3 fatty acids ('fish oil'), but this type of fatty acid is not added to standard infant formula. Hadders: ‘Various studies have shown that adding omega-3 fatty acids to formula helps babies to develop during the first three months of their life. We wanted to know whether this benefit was still evident by the time the children went to school.’

Research set-up

Hadders and her colleagues looked into whether adding omega-3 and omega-6 fatty acids to the formula of healthy, full-term babies had an impact on the functioning of the brain at 9 years of age. They studied 123 children who had been fed formula without fatty acids, 91 children who had been raised on formula with fatty acids and 127 children who had been breast fed. The study also made a distinction between mothers who smoked during pregnancy and mothers who did not.

Effect of added fatty acids

The children who had been fed formula with added fatty acids scored slightly less well in planning and organizing. The impact of the fatty acids was also related to the mother’s smoking habits during pregnancy. Smoking during pregnancy is known to have a negative effect on children’s IQ. This study supported the existing evidence. Fortunately, most mothers do not smoke while they are pregnant. The children born to the mothers who did smoke and were fed formula containing fatty acids did not only have problems planning and organizing, but also had more difficulty learning and remembering things, and a lower verbal IQ. A low verbal IQ means that they have a smaller store of words and knowledge at their disposal. In the small group of mothers who continued to smoke during pregnancy, the drop in the children’s IQ caused by smoking was ‘repaired’ by the omega-3 and omega-6 fatty acids.