The Impact of Breastmilk on Early Brain Development in Premature Infants
by Anne Eglash MD, IBCLC, FABM
What is the relationship between type of feeding and brain development among preterm infants?
There are several studies ( https://lacted.org/questions/0230-breastfeeding-child-iq/) demonstrating that formula fed infants have a higher risk of lower IQ. The association between infant feeding and cognition exists for both premature and term infants.
A 2022 Australian prospective study of 586 infants born <33 weeks gestation found that maternal milk feeding during the NICU stay and after discharge was associated with improved school-age performance IQ and academic achievement at 7 years of age.
The study reviewed for today’s question was done in China, where the authors report having the second greatest number of preterm births in the world. Among these preterm infants, 60.6% have cerebral palsy, 55% have learning disabilities upon entering school, and 20% need special education. Knowing the association between infant feeding and cognitive development, the researchers evaluated brain gray matter structure and function using MRI technology to detect differences based on infant feeding.
Thirty-four breastmilk-fed infants and 22 formula fed infants, all born ~ 32 weeks gestation, underwent brain MRIs at 40 weeks corrected (2 months after birth), after sedation with chloral hydrate.
They found that the formula fed infants had less activation of the R superior temporal gyrus as compared to the breastmilk fed infants. The formula fed infants had less gray matter volume in the bilateral frontal lobe, L caudate nucleus and R temporal lobe as compared to the breastmilk fed infants.
This is one of several studies showing less robust brain development and lower cognitive performance in formula fed infants. According to the authors of this study, what nutritional factors in breastmilk may account for this difference in brain development? Choose 1 or more:
- Docosahexaenoic acid (DHA)
- Long chain polyunsaturated fatty acids
- Sialic acid
See the Answer
The prevailing consensus from large epidemiological studies is that breastfeeding is associated with improved IQ and cognitive functioning in later childhood and adolescence. Current research is exploring the association between breastfeeding and early brain development in preterm infants.
To explore the differences in brain gray matter between breastmilk-fed and formula-fed preterm infants using structural and functional magnetic resonance imaging.
A convenience sample of breastmilk-fed preterm infants (n = 34) and formula-fed infants (n = 22) aged approximately 32 weeks. At near term-equivalent age, MR scanning was performed. Gray matter structural and functional differences between the two groups were assessed using MATLAB software for voxel-based morphometry (VBM) and amplitude of low-frequency fluctuation (ALFF) analysis.
Maternal and neonatal demographic characteristics showed no significant difference between the two groups. Breastmilk-fed infants had greater regional gray matter volume on MRI than formula-fed infants in multiple brain regions, including the bilateral frontal lobe (BA11, BA46), right temporal lobe (BA37), and left caudate nucleus, at a statistical threshold of p40 voxels. Compared with formulafed infants, breastmilk-fed infants showed increased brain activation on fMRI in the right superior temporal gyrus (BA41).
Breastmilk-fed infants had greater regional gray matter development and increased regional gray matter function compared with formula-fed infants at near term-equivalent age, suggesting breastmilk feeding in the early period after birth may have some degree of influence on early brain development in preterm infants.
Lactose, the major digestible carbohydrate in breastmilk, and lactoferrin, a major protein that is anti-infective, are not mentioned as central factors in brain development.
This study demonstrates concrete measurable data that supports the association between infant feeding type and cognition/brain development. It is easier to argue that cognitive differences based on feeding type may be due to nurturing, such as differences in nutrition, educational experiences, sleep quality, etc. MRI differences in brain development are harder to explain by nurturing, especially when demonstrated 8 weeks after birth and substantial time in the NICU. One limitation is that the researchers didn’t report any information on time spent skin to skin. Both groups were fed via gavage.
This is not the first study to demonstrate brain differences on MRI based on infant feeding. The authors provide a nice review of the published evidence to date that corroborates their findings.