To save a child who is hungry, aid workers have long used one certain treatment: food. But a new study suggested that giving their gut bacteria as food is also as important—or even more important—than feeding their stomachs. during a head-to-head comparison against a major for malnutrition, a new supplement designed to encourage helpful gut bacteria led to signs of improved growth and more weight gain, despite having 20% lower calories. The study also points on 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.
Around 30 million children around the world are starving so much that their bodies are being weakened. Their growth declines, their immune systems become less active, and their nervous systems become unable to develop in proper way. To fight malnutrition, health clinics frequently administer prepackaged, ready-to-use supplementary food (RUSF), which is easy to keep in stock and turns into goo after kneading. But malnourished children’s health improvements are rarely permanent, and many never completely recover, even after they eat a sufficient amount of food.
“It’s a problem that previously didn’t have an available solution,” said Ruslan Medzhitov of Yale University who is an immunologist but he is not involved with the work.
For over 10 years, Jeffrey Gordon of Washington University School of Medicine in St. Louis, who is a microbiologist, has conducted study on the role the microbiome plays in malnutrition recovery. He and his colleagues found that 15 key bacteria are needed for usual growth in some animals, and to some degree people, and that children whose microbiomes become unable 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 says.
So he and Tahmeed Ahmed, a malnutrition expert scientist who is leading the ICDDRB in Dhaka, Bangladesh, tried with colleagues to discover which of a half dozen combinations of easy-to-obtain foods most encouraged the growth of these healthy bacteria. In the latest 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.
Around 120 malnourished children living in a slum in Dhaka got either MDCF-2 or the standard RUSF supplement twice each day for 90 days. Every 2 weeks during treatment, and again 1 month after treatment finished, the researchers weighed and measured the children, sampled their blood, and examined the bacteria in their feces.
Not only did MDCF-2 boost blood components linked to growth— for example, proteins required 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 said. First, the team needs to introduce a simpler formulation that can be stored for months—at present, the supplement is made fresh—and easy for mothers to obtain and use. Furthermore, larger testing need to be done abroad, 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.”
