Q: Why do beans cause gas? How can I prevent this?
A: Beans contain complex sugars called oligosaccharides, which are fermented by bacteria in the intestines, producing gas. Navy and lima beans are the worst offenders. Eating beans more often can lessen the problem.
Soaking the beans and changing the water before cooking reduces the amount of flatulence-producing substances. Adding some baking soda to the soaking water may also help a bit—but can increase the loss of B vitamins.
You can also use products such as Beano (available in generic form), which come as tablets or drops that you swallow with the beans or add to them. These contain an enzyme called alpha-galactosidase, which breaks down some of the complex sugars in beans that we don’t digest.