Effects of a specific synbiotic blend on fecal short-chain fatty acids and gut inflammation in cow's milk-allergic children receiving amino acid–based formula during early life: results of a randomized controlled trial (PRESTO study)

Abstract

Consumption of an amino acid-based formula (AAF) with added synbiotics [short-chain oligofructose and long-chain inulin (scFOS/lcFOS, 9:1 ratio) and Bifidobacterium breve M-16V] (AAF-S) beneficially impacts the gut microbiome of infants with cow's milk allergy (CMA). We assessed the effect of consuming AAF with or without synbiotics by children with CMA for 12 months on their fecal (branched) short-chain fatty acids (SCFA/BCFA) concentrations, and on gut barrier and inflammation markers (Netherlands Trial Register NTR3725). Feces and saliva were collected from 161 children (≤13 months) with IgE-mediated CMA at baseline, 6 and 12 months after enrollment, and at 24 and 36 months follow-up. Fecal SCFA and BCFA were analyzed by gas chromatography, and gut barrier and inflammation markers were measured in saliva/feces by ELISA or ImmunoCAP. At 6 months, children receiving AAF-S had significantly lower fecal propionate, valerate and BCFA concentrations compared to children consuming AAF. The percentage of propionate from the total 6 SCFA/BCFA (acetate + butyrate + propionate + valerate + isobutyrate + isovalerate) was significantly lower, while the percentage of acetate from the total 6 SCFA/BCFA was significantly higher in the AAF-S group. There were no significant differences between groups in fecal concentrations of butyrate at 6 months, nor in SCFA or BCFA at baseline and after 12, 24 or 36 months. Intestinal inflammation and barrier markers did not differ between groups. Addition of synbiotics to AAF brings concentrations of key fecal microbial metabolites more in line with patterns observed in healthy breastfed infants. The effects on SCFA and BCFA concentrations were transient and only seen at 6 months.