Long-chain polyunsaturated fatty acids, breastmilk, and infant cognition

A lot has been written about improving infant cognition and breastfeeding, even on this blog (More evidence that breastfeeding improves cognitive development).  Formula companies in their efforts to duplicate the nutritional value of breast milk have supplemented with a number of agents, including long-chain polyunsaturated fatty acids (LCPUFA).  But, does this work?

A meta-analysis of LCPUFA supplementation failed to show any significant effect on early infant cognition (Pediatrics 2012; 129: 1141-49).  Twelve trials with 1802 infants met inclusion criteria.  Included trials were randomized clinical studies that measured cognition with Bayley Scales of Infant Development.

LCPUFAs have been hypothesized to be a potential reason for improved cognition.  LCPUFAs are vital for cell membranes and play a critical role in development and growth.  The two main LCPUFAs are docosahexaenoic acid (DHA) and arachidonic acid (AHA). “An estimated 30-fold increase in the amount of DHA and AA in the infant forebrain occurs between the last trimester of pregnancy and the first 2 years of life.”

The authors note that while breastfed babies tend to have higher intelligence, confounding factors have made it difficult to determine whether actual nutritional differences in breast milk are the reason for this difference.  On average, breastfeeding mothers have higher intelligence, larger incomes, and spend more time with their infants.  Thus, bonding/social interactions as well as other breast milk properties (eg antimicrobial, antiinflammatory, and immunomodulatory) may be important factors.

On the same subject, a second article in the same issue (Pediatrics 2012; 129: 1134-40) also showed that breastfed infants had slightly improved cognitive development compared with formula-fed babies (both cow’s milk and soy formula).  This conclusion was based on Bayley Scales of Infant Development and the Preschool Language Scale-3.  In total, this study examined 391 infants at ages 3, 6, 9, and 12 months.  The authors state that “models were used while adjusting for socioeconomic status, mother’s age and IQ, gestational age, gender, birth weight, head circumference, race, age, and diet history”  –that’s a lot of variables to adjust!

More on breast milk from previous blog entries:

Breastfed babies less likely to develop fatty liver

Breastfeeding: protection from asthma