How Gut Microbes Can Combat Malnutrition

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SEATTLE — Two studies recently conducted by the Washington University School of Medicine in St. Louis demonstrated the causality between underdeveloped gut microbes and the detrimental effects of malnutrition.

Even food therapies to address malnutrition have not yet been able to solve the long-term problems it causes, which include stunted growth, abnormalities in neurodevelopment and ill-functioning immune systems. However, the findings in these studies give way to discovering solutions that address the root of the problem, not just the symptoms.

One of the studies, published in Science, tested the microbiota (or the normal, helpful gut microbes) of healthy and malnourished Malawian children six to 18 months of age by comparing two groups of mice born without microbiota. The gut microbes in malnourished children are less mature than that of well-nourished children. One group of mice was implanted with the mature microbiota of the well-nourished children and the other with that of malnourished children. Then, the two groups were fed the exact same diet, representative of a Malawian diet that did not meet full nutritional requirements that humans or mice need.

The results, according to the study, demonstrated that the mice with the microbiota from well-nourished children developed healthily and normally, while the others had problems with skeletal development, growth, and the metabolic processes in the liver, muscles and brain. Additionally, while the healthy mice gained mass in the form of lean muscle, typical in healthy development, those with the microbiota of malnourished children gained mass in the form of fat.

Speaking to the benefits and shortcomings of current nutritional therapies, Jeffrey I. Gordon, MD and one of the leaders of the study explained to The Source, “Current ‘ready to use’ therapeutic foods have reduced mortality from malnutrition, but these children continue to show lingering long-term effects, including stunted growth, impaired neurodevelopment and dysfunctional immune systems.”

When the groups of mice were placed together, microbiota were transferred between groups, as mice, like other rodents, eat each other’s feces. The researchers discovered that when the mice with underdeveloped microbiota acquired the mature microbiota, the problems they were having, representative of the long-lasting effects of malnutrition, began to correct.

The second study, published in Cell, demonstrated a link between the sugars carrying sialic acid, found in breast milk, and healthy development. These sugars, less prevalent in mothers of undernourished babies than in mothers of healthy ones, were replicated in the study using cow’s milk due to difficulties obtaining breast milk.

The researchers purified the sugars to replicate the characteristics of those found in breast milk, called sialylated bovine milk oligosaccaraides (S-BMOs). They used three groups of mice with the same microbiota. Each group ate the same kind of food with the same amount of calories. However, one group’s food contained S-BMOs, another’s contained a different sugar, not containing sialic acid, found in baby formula and the third group had no added supplements.

The group that ate S-BMOs developed substantially better than the others. When the experiment was conducted using germ-free mice, the mice eating S-BMOs no longer grew substantially more than the other two; the effects were cancelled by the lack of microbiota. When the experiment was tested with piglets, who are more similar to humans than mice according to The Source, it yielded the same results.

According to Nature, malnutrition leads to approximately 50 percent of mortality rates for children under the age of five, since the weakened immunity caused by malnutrition makes people substantially susceptible to infection and contracting diseases.

Gordon optimistically expressed to The Source what this could mean for the future of food therapy: “We hope that these next-generation, food-based interventions will produce durable repair of microbiota immaturity in malnourished children and produce better long-term clinical outcomes.”

Laura Isaza

Photo: Flickr

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Laura Isaza

Laura writes for The Borgen Project from Seattle and her favorite quote is found in the first three sentences of the fifth chapter of Hemingway's A Moveable Feast.

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