Discussion
weight gain, ’
MALNUTRITION
Here we illustrate an approach for characterizing the gut microbiome targets and structure–function relationships of a therapeutic food—in this case, MDCF-2. MDCF-2 produced significantly greater weight gain during a 3-month, randomized controlled study of 12- to 18-month-old Bangladeshi children with MAM compared with a conventional, more calorically dense RUSF. We focused on MAGs, specifically (1) treatment-induced changes in the expression of carbohydrate metabolic pathways in MAGs whose abundances were significantly associated with weight gain (WLZ); and (2) MS analysis of the metabolism of glycans present in the two food formulations. Quantifying monosaccharides, glycosidic linkages and polysaccharides present in MDCF-2, RUSF and their component ingredients revealed that MDCF-2 contains more galactans and mannans (for example, galactan, arabinogalactan I, galactomannan, β-mannan and glucomannan). Two types of comparisons were performed of the transcriptional responses of MAGs that were significantly associated with WLZ: one involved study participants who had consumed MDCF-2 versus RUSF, and the other focused on MDCF-2-treated children in the upper versus lower quartiles of WLZ response. The results revealed that two Using UHPLC–QqQ-MS, we were able to identify statistically significant changes in glycan composition in the faeces of children consuming a therapeutic food, even in the face of complex and varied background diets. Notably, although the intake of MDCF-2 did not differ between children in the upper and lower quartiles of clinical (WLZ) response, children in the upper quartile trended toward diets containing more legumes and nuts compared with those in the lower quartile. The legumes and nuts food group includes major components of MDCF-2. We postulate that MDCF-2 ‘kick starts’ a microbiome response that includes changes in the fitness and expressed metabolic functions of key growth-associated bacterial strains, such as One definition of ‘microbiome repair’ in children with malnutrition is a rebalancing of the representation and expressed functions of beneficial organisms so that it assumes a configuration that is more conducive to healthy microbiome–host co-development. Linking dietary glycans and microbial metabolism in this manner provides a starting point for culture-based initiatives designed to retrieve isolates of these ‘effector’ taxa for use as potential probiotic agents, or if combined with key nutrients that they covet, synbiotic formulations for repairing perturbed microbiomes that are insufficiently responsive to food-based interventions alone.The link between MDCF-2 treatment, 