close
Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Jan 1:184:372-385.
doi: 10.1016/j.neuroimage.2018.09.015. Epub 2018 Sep 7.

The effects of breastfeeding versus formula-feeding on cerebral cortex maturation in infant rhesus macaques

Zheng Liu  1 , Martha Neuringer  2 , John W Erdman Jr  3 , Matthew J Kuchan  4 , Lauren Renner  5 , Emily E Johnson  5 , Xiaojie Wang  1 , Christopher D Kroenke  6
Affiliations

The effects of breastfeeding versus formula-feeding on cerebral cortex maturation in infant rhesus macaques

Zheng Liu et al. Neuroimage. .

Abstract

Breastfeeding is positively associated with several outcomes reflecting early brain development and cognitive functioning. Brain neuroimaging studies have shown that exclusively breastfed children have increased white matter and subcortical gray matter volume compared to formula-fed children. However, it is difficult to disentangle the effects of nutrition in breast milk from other confounding factors that affect brain development, particularly in studies of human subjects. Among the nutrients provided by human breast milk are the carotenoid lutein and the natural form of tocopherol, both of which are selectively deposited in brain. Lutein is the predominant carotenoid in breast milk but not in most infant formulas, whereas infant formulas are supplemented with the synthetic form of tocopherol. In this study, a non-human primate model was used to investigate the effects of breastfeeding versus formula-feeding, as well as lutein and natural RRR-α-tocopherol supplementation of infant formula, on brain maturation under controlled experimental conditions. Infant rhesus macaques (Macaca mulatta) were exclusively breastfed, or were fed infant formulas with different levels and sources of lutein and α-tocopherol. Of note, the breastfed group were mother-reared whereas the formula-fed infants were nursery-reared. Brain structural and diffusion MR images were collected, and brain T2 was measured, at two, four and six months of age. The mother-reared breastfed group was observed to differ from the formula-fed groups by possessing higher diffusion fractional anisotropy (FA) in the corpus callosum, and lower FA in the cerebral cortex at four and six months of age. Cortical regions exhibiting the largest differences include primary motor, premotor, lateral prefrontal, and inferior temporal cortices. No differences were found between the formula groups. Although this study did not identify a nutritional component of breast milk that could be provided to infant formula to facilitate brain maturation consistent with that observed in breastfed animals, our findings indicate that breastfeeding promoted maturation of the corpus callosum and cerebral cortical gray matter in the absence of several confounding factors that affect studies in human infants. However, differences in rearing experience remain as a potential contributor to brain structural differences between breastfed and formula fed infants.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
An overview of image preprocessing steps for brain volume and DTI analyses. (a) For T1-weighted MP-RAGE images, the following operations were performed: (1) averaging with motion correction was used to generate a merged structural image; (2) intensity bias field correction was used to correct the intensity bias in the final structural image; (3) skull-stripping was used to extract brain region. (b) For DTI images, (1) the “topup” function in FSL was used to estimate and correction susceptibility induced distortion; (2) skull-stripping was performed by using and affine transformation of the brain mask to the corresponding MP-RAGE image; (3) the “dtifit” function was used to estimate diffusion tensor parameters, such as FA, MD, eigenvectors and eigenvalues. After these procedures, MRI data were prepared for volumetric analysis and regional analysis of DTI paremeters.
Figure 2.
Figure 2.
Brain template images for the breastfed group with anatomical labels for 2, 4 and 6 months of age. In (a)-(c), labels are overlaid on axial T1-weighted brain template slices for 2, 4 and 6 months, respectively. The overlays over the left hemisphere are six cerebral cortex regions: frontal (red), sensory/motor (green), temporal (blue), parietal (yellow), occipital (cyan), and allocortex (magenta); overlays over the right hemisphere are six WM regions: frontal (red), internal capsule (green), temporal (blue), parietal (yellow), occipital (cyan), and external extreme capsule (magenta). Images in (d)-(f) are axial T1-weighted brain template slices for 2, 4 and 6 months, respectively, (g)-(i) are average T2-weighted slices for 2, 4 and 6 months, respectively, (j)-(l) are average FA slices for 2, 4 and 6 months old, respectively, and (m)-(o) are diffusion tensor colormap images, in which the intensity indicates the degree of diffusion anisotropy, and the color indicates the direction of least restricted diffusion, with red corresponding to left/right, green corresponding to rostral/caudal, and blue corresponding to dorsal/ventral. All images are constructed from the breastfed animals and located in the same coordinates with the same locations.
Figure 3.
Figure 3.
Brain volume boxplots for breastfed, supplemented and unsupplemented formula-fed animals at 2-, 4- and 6-month time points. All data values are overlaid on boxplots. Outlier data values (greater than q3+1.5(q3-q1), or less than q1−1.5(q3-q1), where q1 and q3 are the first and the third quartiles, respectively) are indicated as red “+” symbols. No outliers were excluded from statistical analyses presented in the text. (a) Total brain volumes (TBV), (b) The percentage of TBV occupied by WM and (c) cerebral cortical GM. For all of regions, main effects of age were observed with p<0.01. After 3 post-hoc pairwise comparison, significant increases were observed for TBV and WM from 2 to 4 months and from 4 to 6 months, and significant reductions were observed for cerebral cortical GM from 2 to 4 months and from 4 to 6 months. No significant differences between diet groups, nor age-by-group interactions, in the analysis of brain volume.
Figure 4.
Figure 4.
Averaged T2 boxplots from all three groups at three time points. (a) WM, (b) corpus callosum, and (c) cerebral cortical GM. In all regions, main effects of age were observed with p<0.01. Post-hoc analyses with Tukey-Kramer adjustment identified statistically significant reductions in T2 between 2 and 4 months and between 4 and 6 months. In corpus callosum and cerebral cortical GM, T2 only decreased significantly between 2 and 4 months. No significant main effects of group or ageby-group interactions were observed. Outlier data points, as defined in the Figure 3 caption, are indicated as red “+” symbols, but were included in all analyses described in the text.
Figure 5.
Figure 5.
Analysis of FA values in the corpus callosum. Panels (a)-(c) show overlays of three corpus callosum regions with FA images for 2, 4 and 6 months of age as underlays (red=splenium, green=body, and blue=genu). Panels (d)-(f) show FA boxplots for all ages and groups in the splenium, body and genu of the corpus callosum, respectively. For all regions, main effects of age were observed with p<0.01 and post-hoc analysis with Tukey-Kramer adjustment indicate that FA increases from 2 to 4 months and from 4 to 6 months. In addition, main effects of diet group were observed in the genu and splenium (p<0.01). Post-hoc analysis with Tukey-Kramer adjustment indicates that the breastfed group has larger FA in the genu than the lutein supplemented formula-fed group, as well as larger FA in the splenium than the other two formula-fed groups (p<0.05). Outlier data points, as defined in the Figure 3 caption, are indicated as red “+” symbols, but were included in all analyses described in the text. Plots in (g)-(i) are correlations between mean corpus callosum FA values measured at different ages across individual subjects. Values are highly correlated for each pair of time points.
Figure 6.
Figure 6.
Panels (a)-(c) show the FA values with overlaid 1st eigenvectors of the same animal from the breastfed group at 2, 4 and 6 months of age, respectively. All FA maps and corresponding eigenvectors were aligned to the template space with a rigid-body linear transformation. The cerebral cortex is associated with radially-oriented diffusion anisotropy. Panel (d) shows a boxplot of cerebral cortical GM FA for each group at three time points. A significant group-by-age interaction was observed with p=0.016. In the breastfed group, mean FA was significantly larger at 2 months than at 4 and 6 months (p<0.01). However, in formula-fed groups, no significant age-related changes in FA were observed. Outlier data points, as defined in the Figure 3 caption, are indicated as red “+” symbols, but were included in all analyses described in the text. Panel (e) shows the correlations of mean FA values in the cerebral cortex GM for each animal between 4 and 6 months of age.
Figure 7.
Figure 7.
Clusters of cerebral cortical surface regions exhibiting significantly different FA between breastfed and formula-fed groups, projected onto the cortical surface. Adjusted p-values are mapped to the cortical surface and are shown in (top row) medial views (middle row) dorsal and ventral views, and (bottom row) lateral views for (a) the test for voxels in which cortical FA in breastfed animals is less than cortical FA in unsupplemented animals and (b) the test for voxels in which cortical FA in breastfed animals is less than cortical FA in supplemented animals. Arrowheads indicate stripes of reduced FA in breastfed animals in inferior temporal lobe observed on both hemispheres (see text for details).
See this image and copyright information in PMC

References

    1. A.A.o. Pediatrics, Breastfeeding and the Use of Human Milk, Pediatrics, 129 (2012) e827–e841. - PubMed
    1. Martin RM, Kramer MS, Patel R, Rifas-Shiman SL, Thompson J, Yang S, Vilchuck K, Bogdanovich N, Hameza M, Tilling K, Oken E, Effects of Promoting Long-term, Exclusive Breastfeeding on Adolescent Adiposity, Blood Pressure, and Growth Trajectories: A Secondary Analysis of a Randomized Clinical Trial, JAMA Pediatr, DOI 10.1001/jamapediatrics.2017.0698(2017) e170698. - DOI - PMC - PubMed
    1. Owen CG, Martin RM, Whincup PH, Smith GD, Cook DG, Does breastfeeding influence risk of type 2 diabetes in later life? A quantitative analysis of published evidence, Am J Clin Nutr, 84 (2006) 1043–1054. - PubMed
    1. Oddy WH, Longer duration of exclusive breastfeeding associated with reduced risk of childhood asthma up to age six, Evid Based Nurs, 16 (2013) 18–19. - PubMed
    1. Kramer MS, Kakuma R, Optimal duration of exclusive breastfeeding, Cochrane Database Syst Rev, DOI 10.1002/14651858.CD003517.pub2(2012) CD003517. - DOI - PMC - PubMed

Publication types