Stomach gurgling and flatulence can be unwelcome rewards for having healthfully upped your intake of fruits, vegetables and other high-fiber foods that produce gas in your intestines. These symptoms can also be a sign of lactose intolerance, even if you've never had it before. “We are all much more likely to become lactose intolerant after age 40 because as we get older, there's a marked decrease in the amount of lactase [the enzyme needed to digest the lactose in milk and other dairy products] that's produced in our intestines,” says Dr. Cynthia Yoshida, a professor of gastroenterology at the...