By Stephen E. Goldfinger, M.D., Harvard Medical School, for MSN Health & Fitness 

Q: I'm 48-years old and have suddenly started suffering from lactose intolerance. I am avoiding all kinds of dairy to prevent the bloating and pain. I thought that was the end of it, but other foods are bothering me now, like peanuts and meats. The list of foods I can eat is shrinking by the day. Do you think I might have a serious problem in my digestive system? Should I go for intensive testing?  

A: Lactose intolerance is caused by a deficiency of the enzyme lactase, which is present at the surface of cells that line the small intestine. This enzyme cleaves lactose, which cannot be absorbed, into two smaller sugars that are readily taken up into the body. If there is not enough lactase present, undigested lactose passes into the colon, where bacteria ferment it into smaller molecules that can cause gas pains, bloating, and loose bowel movements. 

When lactase deficiency is inherited, as is often the case, the symptoms I describe come on early in life. But when lactose intolerance begins at your age, one must consider an acquired disorder that might be affecting the cells that line the small intestine. For example, one possibility could be celiac disease. Celiac disease, also called celiac sprue, is a disorder of the intestine caused by a reaction to dietary gluten.  

Especially considering the other food intolerances you have recently noticed, my recommendation would be that you seek medical evaluation to unravel what might be going on. The symptoms you described are not usually associated with a serious medical condition. But, the situation definitely deserves attention.

Generally, when new and prominent digestive symptoms arise for the first time in an adult, they ought to be checked out.