Feeding the microbiome to help malnourished children
Recent findings from an ongoing series of studies of malnourished children demonstrate that complementary foods (i.e., foods given in addition to those consumed in the diet) that are designed to boost maturation of their gut microbiome can improve markers of normal growth, neural development, and immune function in these children. Research has shown that adequate recovery from severe childhood malnutrition requires more than access to healthy food (or breast milk in the case of the youngest children). Even when supplemented with life-saving, so-called “complementary” or “therapeutic” foods high in calories and protein, severely malnourished children do not recover completely and remain moderately malnourished in a way that can still cause stunting and other effects on health. Studies in resource-limited populations living in Bangladesh and Malawi have shown that malnutrition leaves a lasting impression on a child’s developing gut microbiome—the collection of microbes and their genetic material—resulting in an underdeveloped, “immature” microbiome less capable of supporting human metabolism and growth. Building upon their past findings, scientists set out to identify a combination of food ingredients that would support maturation of the microbiome to encourage healthy growth and development of malnourished children. They measured health and metabolic indicators, as well as microbes present, in severely malnourished young girls and boys, ages 6 to 36 months, living in Bangladesh over the course of treatment with one of three types of “conventional” formulations of therapeutic foods, consisting of either rice and lentils, chickpeas, or a commercially available peanut-based food. This initial study provided a baseline of information on how the gut microbiome typically changes during treatment with conventional complementary foods, as children made a partial recovery from severe to moderate malnutrition with continued immaturity in their microbiomes. In parallel, to identify potential complementary foods that could be more effective in improving the gut microbiome during malnutrition, they transplanted gut microbes from severely malnourished children into male mice raised in sterile conditions, to test microbial levels in response to 12 food ingredients found in the Bangladeshi diet. Based on these findings, they identified combinations of these 12 complementary food ingredients that, given together with a representative diet consumed by malnourished children, most improved the microbiome and growth markers in these mice and also in piglets similarly given microbes from the children. Coming full circle back to humans, the investigators then conducted a randomized controlled feeding study in children ages 12 to 18 months with moderate malnourishment. This study compared three complementary food combinations with the best results on the gut microbiome in the animal models. When the complementary foods were given in addition to the children’s regular diet, one combination in particular—containing chickpea, soy, peanut, and banana—led to improved markers of growth, neural development, and immune function that more closely resembled those seen in healthy children. Through developing and testing complementary foods that are custom-designed to reverse microbiome immaturity caused by malnutrition, scientists hope to provide the means to more fully restore health to these children.
Gehrig JL, Venkatesh S, Chang HW,…Gordon JI. Effects of microbiota-¬directed foods in gnotobiotic animals and undernourished children. Science 365: pii: eaau4732, 2019.