HOW MUCH LACTOSE FOR MILK DIARRHEA?

Report #7119; 5/26/97

One out of every two people on this earth develops gas and cramping after drinking milk. Most can drink milk without suffering gas, provided that they don't take too much at one time and take the milk with food.

Milk contains lactose, a molecule containing two single sugars, tied together. The intestines of humans allow only single sugars to pass into the bloodstream, so lactose, a double sugar in milk, cannot be absorbed, and therefore passes to the large intestine, where bacteria ferment the double sugar to cause gas and cramping. The intestines of most humans contain an enzyme called lactase, that splits the double sugar into single sugars which are easily absorbed into the bloodstream and never reach the large intestine and therefore, do not cause gas.

If you have lactose intolerance, treatment is to keep the double sugar from reaching the bacteria in your colon. You can buy an over- the- counter preparation called lactase, the enzyme that splits the double sugar in milk to single sugars. Add the powder to the milk, leave it in the refrigerator overnight and you can drink the milk safely on the next morning. Many milk-intolerant people can drink small amounts of milk with each meal safely (1,2).

By Gabe Mirkin, M.D., for CBS Radio News