Effects of long-chain polyunsaturated fatty acid supplementation of infant formula on cognition and behaviour at 9 years of age.

Aim: Long-chain polyunsaturated fatty acid (LCPUFA) supplementation of infant formula may have a beneficial effect on cognitive development. This study aimed to investigate the effect of LCPUFA formula supplementation primarily on cognition and secondarily on behaviour at age 9 years. Special attention was paid to the potentially modifying effect of maternal smoking during pregnancy.

Method: A double-blind, randomized control study was performed in two groups of healthy infants born at term: one group, constituting the control group, received standard formula (n=169) and another group received standard formula supplemented with LCPUFAs (n=146). A breastfed group (n=159) served as an additional reference. At 9 years of age, 72% of the children (control group: n=123; 71 males, 52 females; LCPUFA group: n=91; 42 males, 49 females; breastfed group: n=127, 64 males, 63 females) underwent extensive cognitive and behavioural testing.

Results: An interaction between infant nutrition and smoking during pregnancy was found. Among children exposed to smoking during pregnancy, LCPUFA supplementation was associated with higher mean verbal IQ scores (p=0.007) and learning and memory (p=0.006). Among children not exposed to smoking during pregnancy, LCPUFA supplementation was associated with lower mean verbal memory scores (p=0.003). Executive function scores were significantly lower in the LCPUFA-supplemented group than in the control group (p=0.001). Breastfeeding was associated with better performance on IQ (p=0.005).

Interpretation: No consistent beneficial effect of LCPUFA formula supplementation on cognitive development in term-born infants was found. The study confirmed that breastfeeding is associated with better cognition.