Kwashiorkor is a form of malnutrition that triggers swelling in the belly and vulnerability to diseases. But no one knows why if afflicts some and not others.
New research transplanting gut bacteria from human twins into mice could help explain why it develops.
Study researcher Michelle Smith of Washington University in Saint Louis looked at kwashiorkor in Malawi – where tens of thousands of children are affected. Up to 15% of these cases are fatal.
Poor diet is a cause, but no one knows why some children are afflicted while others living in the same condition aren’t. Nature reports:
In tracking 317 pairs of twins in Malawi for the first three years of their lives, the group found that kwashiorkor affected both twins in a pair in only 7% of cases, and in 50% of cases, only one of the twins.
Researchers took fecal samples from a set of Malawian twins – one who had kwashiorkor and one who didn’t – and used them to create gut bacteria for mice raised in clean, air-tight, germ-free environments. Using this near-perfect mimic, the researchers observed how the bacteria react to changes in diet.
- First, the mice had 3 weeks of a typical Malawian diet of mostly corn flour and some vegetables.
- Then for 2 weeks, they feasted on a diet of ready-to-use therapeutic food, which is a high-calorie peanut buttery, milky, sugary food. It packs in 8 times as many calories as the above fare.
- And then they spent 2 weeks back on the Malawian diet.
The mice with gut bacteria from the sibling with kwashiorkor lost more weight on the corn diet and gained more on the peanut butter diet – compared with the mice with gut bacteria from the healthier sibling.
Differences in gut bacteria might affect how susceptible people are, since they change how people absorb minerals and vitamins from their food. So one possible conclusion is that the gut bacteria of the sick twin make it difficult to absorb the limited nutrients and calories of the meager diet.
They also found that the species composition of those bacteria from the kwashiorkor child fluctuated more with changes in diet, as did the makeup and abundance of bacterial enzymes [Science].
The mice findings suggest that the makeup of the gut bacteria is important in the response to starvation, says Andrew Serazin of the Bill & Melinda Gates Foundation, which funded the work.
But Smith cautions: “I don’t think it’s not involved. But I can’t say it is, yet.”
Ultimately, Smith would like to identify a bacterium or set of bacteria that protects children from kwashiorkor, and add it to the emergency rations handed out to starving children, or give it to them beforehand.
The study was presented at the International Human Microbiome congress in Vancouver this week.
Image: CDC via wiki
