21. People who are lactose intolerant often produce "bubbles" when they eat dairy products. What causes this reaction to milk, cheese, and other dairy products?
From Quiz I'm Forever Blowing Bubbles
Answer:
They don't produce enough lactase
Lactose is a sugar that is found in milk, cream, cheese, ice cream, and many other dairy products. In order to digest lactose, humans need an enzyme known as lactase that digests the sugars. If an individual does not produce enough lactase, they are not able to digest dairy products. Symptoms of lactose intolerance include bloating, nausea, diarrhea, stomach cramps, and gas. Many non-dairy products can be found in supermarkets that allow those who suffer from lactose intolerance to enjoy dairy-like food items without having to worry about developing "bubbles".