Gastrointestinal effects of introduction of milk proteins in infant's diet

Abstract

[Introduction] Milk is a complex food with 3.3% protein content and is fundamental in the diet throughout the all life and especially during childhood. However, cow`s milk protein allergy (CMPA) is very common in infancy and the only therapeutic option is a dairy elimination diet. The impact of the absence of milk proteins and dairy products in the gut ecosystem development of the infant has rarely been assessed. [Objective] To evaluate the intestinal changes in infants with non-IgE mediated CMPA after successful standardized oral challenges (SOCs) and introduction of milk in their diet. [Methodology] Twelve allergic children (between 1 and 2 years old) that were initially on a milk restriction diet provided stool samples before SOCs, and a week and a month after introduction of milk. Changes in the intestinal microbiota populations were determined by high-throughput sequencing of the 16S rRNA gene, meanwhile diverse microbial metabolites (short chain fatty acids and indoles) were quantified by chromatographic methods. [Main findings] The introduction of milk in infants that developed tolerance acquisition increased significantly the levels of fecal lactic acid bacteria. Microbial metabolites derived from the fermentation of proteins, such as branched chain fatty acids and p-cresol diminished. Statistical differences were observed between infants that were consuming probiotics (Lactobacillus rhamnosus GG) during the restriction diet period and those that were not. [Conclusion] The introduction of dairy products in the diet is accompanied by modifications in the infant gut environment through changes in the microbiota and protein metabolic end-products. Consumption of probiotics may affect the response to SOC with milk.