To save a starving child, aid workers have long used one obvious treatment: food. But a new study suggests feeding their gut bacteria may be as important—or even more important—than feeding their stomachs. In a head-to-head comparison against a leading treatment for malnutrition, a new supplement designed to promote helpful gut bacteria led to signs of improved growth and more weight gain, despite having 20% fewer calories. The study also highlights how important gut bacteria—the so-called microbiome—can be to human health.
“This is an exciting study that promises to bring hope to millions of acutely malnourished children,” says Honorine Ward, a physician scientist at Tufts University School of Medicine who was not involved with the work.
About 30 million children worldwide are so hungry that their bodies are wasting away. Their growth slows, their immune systems don’t work well, and their nervous systems fail to develop properly. To combat malnutrition, health clinics often administer prepackaged, ready-to-use supplementary food (RUSF), which is easy to store and turns into goo after kneading. But malnourished children’s health improvements are rarely permanent, and many never fully recover, even after they eat enough. “It’s a problem that previously didn’t have an available solution,” says Ruslan Medzhitov, an immunologist at Yale University not involved with the work.
For more than 10 years, Jeffrey Gordon, a microbiologist at Washington University School of Medicine in St. Louis, has studied the role the microbiome plays in malnutrition recovery. He and his colleagues discovered that 15 key bacteria are needed for normal growth in mice, pigs, and to some degree people, and that children whose microbiomes fail to “mature” to include these species do not recover from malnutrition as well as children whose gut bacteria do mature. “Current therapies do not repair this disrupted microbiome,” Gordon explains.
So he and Tahmeed Ahmed, a malnutrition expert scientist who heads the International Centre for Diarrhoeal Disease Research in Dhaka, Bangladesh, tried with colleagues to find out which of a half dozen combinations of easy-to-obtain foods most encouraged the growth of these healthy bacteria. In the new study, they tested their best performing candidate: a complex mixture of chickpea, banana, soy, and peanut flours and oils that they call microbiota-directed complementary food No. 2, or MDCF-2.
About 120 malnourished toddlers from a Dhaka slum received either MDCF-2 or the standard RUSF supplement twice a day for 3 months. Every 2 weeks during treatment, and again 1 month after treatment ended, the researchers weighed and measured the children, sampled their blood, and analyzed the bacteria in their feces.
Not only did MDCF-2 boost blood components linked to growth—such as proteins needed for the proper development of bones, the nervous system, and the immune system—but it also resulted in a growth rate twice as high, measured by change in a weight-to-length score, as in those receiving RUSF, the researchers report today in The New England Journal of Medicine. What’s more, 21 types of beneficial bacteria increased in abundance. Enhanced growth in children continued even after the treatment ended. “A small amount of this food supplement can actually cure malnutrition in children,” Ahmed concludes.
But becoming standard treatment could take years, Ahmed says. First, the team needs to come up with a simpler formulation that can be stored for months—right now, the supplement is made fresh—and easy for mothers to obtain and use. Moreover, larger trials need to be conducted in other countries, with children followed for up to 5 years to see whether the beneficial effects persist, Ward says.
Meanwhile, the work offers tantalizing hints of how gut bacteria might alter growth. “Different bacteria are beneficial or detrimental at different stages of development,” Medzhitov says. For example, a bacterium linked to the beneficial effects of breast feeding, Bifidobacterium longum, was associated with less improvement in the children in the study. That finding paves the way for development of disease-specific interventions to shape the microbiome, Ward adds.
Until that happens, Gordon and Ahmed are continuing to refine their formulation, and they are eyeing other countries—and communities—for their studies. “I think the remaining challenges are mostly logistical,” Medzhitov says. Gordon agrees, adding that their findings still come down to a simple message: “Healthy children depend … on a healthy microbiome.”