Increased Exclusivity of Breastfeeding Associated with Reduced Gut Inflammation in Infants

Introduction: The development of the intestinal gut is largely influenced by early nutrition. Infant immunity is challenged by the exposure of the gut to foreign bodies, which mediate inflammation of the gut. This study assessed the levels of gut inflammation in relation to the percentage of breastmilk consumed/the exclusivity of breastfeeding in South African infants. This is the first study to examine markers of gut inflammation in infants in relation to exclusivity of breastfeeding measured by a gold standard method. Methodology: Twenty-four black South African infants were included in this study. The categorization of different degrees of exclusivity of breastfeeding was made using an objective gold standard method developed by the International Atomic Energy Agency (deuterium dilution method). Markers of gut inflammation were measured noninvasively by sampling stool from the infants averaging 6 months of age. Gut inflammation was investigated by running multiple Droplet Digital (Bio-Rad, Hercules, CA) polymerization chain reaction tests profiling a panel of five mRNA probes (interleukin-8 [IL-8], S100 calcium-binding protein A8 [S100A8], Toll-like receptor-4, human leukocyte antigen on chromosome 6 region 6p21.31, and defensin alpha 8). These mRNA biomarkers expressions were tested in proportion to number of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) copies as GAPDH is constitutively expressed in most cells. Results: Two previously described robust mRNA markers of gut inflammation (S100A8 and IL-8) were found to correlate significantly to the percentage of breastmilk intake (r(2)=0.4302, p=0.0004 and r(2)=0.3633, p=0.002, respectively) in the range of 75-100% in 22 samples analyzed. Conclusions: This study using objective methodology has shown that higher percentages of breastmilk intake are associated with significantly lower levels of gut inflammation. This further supports the health benefits observed in exclusively breastfed infants.