Malnutrition and the Gut Microbiota

Here's an interesting case of malnourished identical twins who present with two distinct types of malnutrition: one's got kwashiorkor, and the other has marasmus. Kwashiorkor is characterized by edema (swelling) and a distended belly (actually a compromised liver) and associated with protein-poor diets; marasmus is more of a wasting disease associated with starvation. Kwashiorkor is a bit more mysterious as a disorder and difficult to treat, for it doesn't always respond to protein supplementation.

Both brothers had identical genomes and were fed the same diet. Researchers found 13 other cases similar to this one, where one twin had kwashiorkor and the other didn't. By transplanting gut microbes from both healthy and kwashiorkor kids into germ-free mice, they found that "a child with kwashiorkor can effectively transmit their symptoms to a mouse by donating their gut microbes." However, mice with the kwashiorkor microbes were fine when fed a normal diet. Only when they ate a starchy diet low in protein did they begin to develop symptoms.

The sample size was small, but I think this is a really interesting development in our understanding of the disorder. I wouldn't be surprised if we started to see enterotypes associated with kwashiorkor in the next couple of years. Fecal transplantation, rather than dietary supplementation with nutrient-dense food packets, might become the norm. Maybe we'll even see the best of both worlds: calorie rich probiotic supplements with specific bacteria added to confer stability to the microbiota and maximize nutrient absorption. Surprisingly enough, that kind of technology might also be applicable to treating obesity, another metabolic disorder with its own set of associated microbes.