Gut microbes can cause severe malnutrition

Study on Malawian children suffering from kwashiorkor establishes the link

By Jyotsna Singh
Published: Friday 01 February 2013

A study of young twins in Malawi in south eastern Africa reveals that simple food intake will not improve the health of some of the world’s malnourished children. Their health depends more on the kind of microbes that inhabit their guts, the study shows. Understanding the role of the gut microbiota in under-nutrition could help devise new ecologically inspired strategies for correcting this problem. Malnutrition is common in Malawi, and children afflicted with kwashiorkor (acute protein deficiency) suffer oedema, liver damage, skin ulceration and anorexia, in addition to wasting.

The study of young twins in Malawi in Africa, reveals that severe, acute form of malnutrition called kwashiorkor is associated with certain gut bacteria, and not nutrition alone. By conducting the study on twins, the researchers could isolate the impact of genetics and household environment.

The study was conducted by Michelle Smith of Center for Genome Sciences and Systems Biology at Washington University in St. Louis, USA, in collaboration with many other researchers and scholars. The conclusions were published in the journal Science on February 1, 2013.

Smith and her team studied 317 pairs of Malawian twins during the first three years of life. During this time, half of the twin pairs were well-nourished. In others, either one or both of the twins developed kwashiorkor. Children with the disorder and their twins were treated with a peanut-based, therapeutic food for nine weeks, as per the standard of care.
Change of treatment protocol

Studies of their gut microbiota revealed that the acutely malnourished children had a different profile of microbes, which became more similar to that of the well-nourished children during the treatment. However, once the treatment stopped and children were put back on village diet, the combination of microbes returned to its earlier state.

To investigate further, the researchers transferred the fecal flora from each of the healthy and sick twins into germ-free mice. The mice that received the microflora from the kwashiorkor twin developed symptoms of malnutrition like their human counterparts. Changes in metabolite profiles and indications of abnormal sulfur metabolism accompanied these shifts in the microbial makeup.

In a related comment in the journal, David A Relman of the Departments of Medicine and of Microbiology and Immunology, Stanford University School of Medicine, says that the understanding could lead to "possible therapeutic approaches that include delivery of defined microbial strains—either alone or as collectives—key nutrients for host and microbiota, molecules that exploit microbiota-host signalling or trigger self-regenerative responses in the gut mucosa and epithelia, and modulator of mucosal immune function."


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