I have lactose intolerance, a decreased ability to digest lactose in dairy products. Gives me pretty awful gas, honestly.
That sounds bad, can you eat cheese or that cause symptoms too?
Cheese is no good, although honestly it depends on how much I eat or drink of a given dairy product. If I eat a little, I'm usually fine.
Do you take anything to help you digest lactose?
Yeah, I can eat Lactaid, which basically is just supplemental lactase, the enzyme that breaks down lactose. With that, I'm golden.
Do you know what percentage of population is lactose intolerant in the U.S.?
I can't speak to the US specifically, but about 65% of the world's population has lactose intolerance to SOME degree.
That is a lot!  Thank god I don't have trouble with lactose I love dairy!
Lactose intolerance
Lactose intolerance is a condition in which people have symptoms due to the decreased ability to digest lactose, a sugar found in dairy products. Those affected vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pain, bloating, diarrhea, gas, and nausea. These symptoms typically start thirty minutes to two hours after eating or drinking milk-based food. Severity typically depends on the amount a person eats or drinks. Lactose intolerance does not cause damage to the gastrointestinal tract.
differ in severity. Most people are able to digest a small quantity of milk, for example in tea or coffee, without suffering any adverse effects. Fermented dairy products, such as cheese, also contain significantly less lactose than plain milk. Therefore, in societies where tolerance is the norm, many lactose intolerant people who consume only small amounts of dairy, or have only mild symptoms, may be unaware that they cannot digest lactose. 
Eventually, in the 1960s, it was recognised that lactose intolerance was correlated with