Kwashiorkor

Interesting and even promising if this holds up: A study using sterile mice given different diets and transplants of gut bacteria from children with and without kwashiorkor suggests that the presence of some bacteria, or (more promisingly) the absence of others, has a strong effect on how well nutrients are absorbed from food. The ones given the bacteria from kwashiorkor children lost more weight on a low nutrition diet of corn flour and a few veggies, and gained it faster on a high nutrition one based on peanut butter. To try to control some of the variables, the children selected were siblings, one of whom got kwashiorkor and the other who did not on the same diet.

The possibility is obvious, and stated in the article--perhaps kwashiorkor can some day be prevented with an innoculating pill.