Microbiota And Infant Growth

More evidence emphasizing the importance of the gut microbiota:
 

Malnutrition in children is a persistent challenge that is not always remedied by improvements in nutrition. This is because a characteristic community of gut microbes seems to mediate some of the pathology. Human gut microbes can be transplanted effectively into germ-free mice to recapitulate their associated phenotypes. Using this model, Blanton et al. found that the microbiota of healthy children relieved the harmful effects on growth caused by the microbiota of malnourished children. In infant mammals, chronic undernutrition results in growth hormone resistance and stunting. In mice, Schwarzer et al. showed that strains of Lactobacillus plantarum in the gut microbiota sustained growth hormone activity via signaling pathways in the liver, thus overcoming growth hormone resistance. Together these studies reveal that specific beneficial microbes could potentially be exploited to resolve undernutrition syndromes.

Therefore: certain phenotypes of organisms (mice, humans, etc.) are due to their gut microbiota, and these phenotypes can to some extent be mimicked by transferring the microbiota from one host to another. Replacing the unhealthy microbiota of malnourished children with that of healthy children enhanced the growth of the malnourished children. Keeping in mind that the human gut microbiota is very sensitive to diet, this underscores the important connections between a healthy diet, a healthy microbiome, and the overall health of the human being.