Beans of all kinds are a natural gas causing substance. They are the only products in nature that will swell to several times their size and appear to be filled with air when they come in contact with water. It is due to this nature of the product that it goes into the human body and behaves likewise as well. Many people do not eat beans as a regular part of their diet. This is the reason that when they do eat beans, they cause noxious flatulence.
However, this condition has nothing to do with any kind of enzymes or anything else. When everyone else eats beans, they also cause noxious flatulence. In this, your friend and his family are not alone. They just feel the difference because they probably eat beans very rarely. One of the ways to get rid of the problem is to simply walk off the gas. A good 20-minute walk when the flatulence is felt most strongly will probably release all the gas trapped in the body and make the person feel better. One reason for the noxious odor could also be that your friend has the general problem of indigestion. In such a case, not only do beans aggravate the problem, the gas released is also strong and bad smelling.
answered by M W