Twins in Malawi helped scientists discover a role the gut microbiome appears to play in severe malnutrition. Photograph courtesy of Tanya Yatsunenko hide caption

itoggle caption Photograph courtesy of Tanya Yatsunenko

Many Haitian children suffer from "stunting" due to inadequate nutrition. Health experts now are trying to prevent this with snacks made from peanut butter, fortified with vitamins and minerals. Alex E. Proimos/via flickr hide caption

itoggle caption Alex E. Proimos/via flickr

Families wait for hours to register at the Yida refugee camp in South Sudan along the northern border in early July. Within a few weeks, the population of the camp more than doubled, leading to shortages of food, water and medicine. Paula Bronstein/Getty Images hide caption

itoggle caption Paula Bronstein/Getty Images

A man prepares an aye-aye, a rare type of lemur found only on the island of Madagascar, for dinner. These primates are an important source of iron and protein despite being critically endangered. Christopher Golden hide caption

itoggle caption Christopher Golden