Over the past few decades, an increase in the prevalence of food allergy has been reported.1,2 Specifically, cow’s milk allergy (CMA) is the most common food allergy in infancy, with an incidence of 2-3% in the first year of life.3 CMA infants and children are known to have an aberrant gut microbiota (dysbiosis) in early life compared to healthy breastfed infants.4,5 Increasing evidence shows that establishing a balanced microbiota is one of the key factors driving the development of the immune system.6,7,8,9,10,11
Clinical and Translational Allergy has published new data from the ASSIGN study. The first publication of the ASSIGN study (Pediatr Res 2018, Candy et al) reported a hypoallergenic amino acid-based formula (AAF), including specific synbiotic ingredients, being able to bring the gut microbial composition of CMA infants closer to that of healthy breastfed infants. The second publication of this study also reported beneficial effects on the gut microbiota composition over the follow up period of 26 weeks. While the first two publications focus on quantitative gut microbiota composition outcomes, the third publication of the ASSIGN study highlights in-depth faecal and salivary microbiota compositions.
This continuous research was designed to investigate the effects of an AAF including specific synbiotics on oral and gastrointestinal microbiota of non-immunoglobulin E (non-IgE) mediated CMA infants in comparison with healthy, breastfed infants.
The ASSIGN study is a prospective, randomized, and double-blind controlled trial in 71 infants with suspected non-IgE mediated CMA and a non-randomized healthy, breastfed reference group of 51 (HBR). An AAF was used as the study formula, consisting of the test formula (including synbiotics: a prebiotic blend of short-chain and long-chain fructo-oligosaccharides and a probiotic strain Bifidobacterium breve M-16V) and the control formula (without synbiotics). The AAF was shown well-tolerated and is a safe and effective approach for the dietary management of non-IgE mediated CMA infants.12,13,14 Bacterial compositions of faecal and salivary samples were profiled and analyzed by sequencing the 16S rRNA gene. The overall bacterial metabolic activity was assessed by measuring faecal sample parameters including pH, short-chain fatty acids (SCFAs), and lactic acids.
The results of this study demonstrated that the synbiotic-containing AAF had a significant impact on the gastrointestinal tract microbiota and only minimal effect on the oral microbiota in saliva samples. Overall, the results confirmed the outcomes of previous ASSIGN publications indicating the AAF including specific synbiotics rebalances the gut microbiota composition and its metabolic activity in non-IgE mediated CMA infants. It was shown to be modulated into a closer microbial composition of a healthy breastfed profile.