Despite screaming into the night, babies’ discomfort rarely includes problems digesting lactose, the sugar in milk. But globally, around 75% percent of adults have some amount of lactose intolerance, also called lactose malabsorption. That’s because as we grow and start eating other foods, most people’s bodies decrease production of lactase, the enzyme that breaks down lactose.
Lactose intolerance is usually harmless, but its symptoms may be quite uncomfortable, including diarrhea, nausea/vomiting, cramps, bloating, and gas. And avoiding foods with lactose can lead to insufficient calcium consumption, which can cause many other problems.
Managing lactose intolerance doesn’t necessarily mean giving up or avoiding all dairy products. Small amounts of dairy—such as a cup of milk—may not cause any symptoms at all. For some people, the solution is to take lactase supplements whenever they consume foods with lactose.
But there may be another way. As microbiologist M. Andrea Azcarate-Peril and her team at the University of North Carolina, Chapel Hill is finding, the microbiota in the intestines can profoundly affect a person’s capacity to consume lactose. Her team is engaged in a clinical trial to increase the numbers of lactose-metabolizing bacteria that live in the gut, which also can be encouraged simply by changing a person's diet in specific ways.
I spoke with Azcarate-Peril about that diet and her team’s research at a chapter meeting of Sigma Xi, which publishes American Scientist.