* Find a Gastroenterologist Lactose Intolerance * What Is Lactose Intolerance? * Lactose Intolerance Causes * Lactose Intolerance Symptoms * Lactose Intolerance Diagnosis * Lactose Intolerance Treatments Related to Digestive Disorders -- Crohn's Complications What Is Lactose Intolerance? Articles OnLactose Intolerance Lactose Intolerance Lactose Intolerance - What Is Lactose Intolerance? * What Is Lactose Intolerance? * Lactose Intolerance Causes * Lactose Intolerance Symptoms * Lactose Intolerance Diagnosis * Lactose Intolerance Treatments Millions of Americans can’t digest a certain sugar in milk and milk products called lactose. If you’re one of them, you have lactose intolerance. -- much milk or milk products you drink or eat. Being lactose intolerant is not the same as being allergic to milk. What Is Lactose? Lactose is the sugar that’s in milk. Our bodies use an enzyme called lactase to break down that sugar so we can absorb it into our bodies. But people with lactose intolerance don’t have enough lactase. It’s produced in the small intestine. Even with low levels of lactase, some people can digest milk products just fine. For people who are lactose intolerant, their low lactase levels gives them symptoms after they eat dairy. What Happens In My Body If I’m Lactose Intolerant? When we drink milk or have a milk-based product, lactase in our small -- body through the small intestines. But people who are lactose intolerant don’t have it so easy. In them, the lactose doesn’t get broken down. Instead, it goes on to the colon, where it mixes with normal bacteria and ferments. It can cause things like gas, bloating and diarrhea. -- In the United States, it’s estimated that just over one-third of people are lactose intolerant. It is most common among: * Asian-Americans * African-Americans -- Continued How Do I Know If I’m Lactose Intolerant? Our bodies react to milk in ways that are easily measured. Two common tests for adults are: * Breath test. This will show if you have high levels of hydrogen when you exhale. If you do, you might be lactose intolerant. That’s because hydrogen is given off when lactose is broken down in the colon. The hydrogen gets taken by the blood up to your lungs, and then you exhale it. * Blood test. This can show how your body reacts after you drink something with a lot of lactose. However, this test is usually not done. -- products, like hard cheese or yogurt, may be easier to digest. Also, there are lots of lactose-free dairy products at the supermarket. Or you can take commonly found over-the-counter supplements (like Lactaid) to break down the milk sugars if you still want the real -- * Beef liver If you have symptoms of lactose intolerance, see your doctor. And if you’re diagnosed with it, talk with her about how to be sure you’re eating right. -- SOURCES: Cleveland Clinic: “Lactose Intolerance.” Mayo Clinic: “Lactose intolerance.” Johns Hopkins Medicine: “Lactose intolerance.” National Institutes of Health: “Lactose intolerance.” National Institutes of Health: “Evolution of lactase persistence: an -- National Institute of Diabetes and Digestive and Kidney Diseases: "Definition & Facts for Lactose Intolerance." -- Pagination Next In Lactose Intolerance Lactose Intolerance Causes Top Picks -- further reading * Slideshow: Lactose Intolerance – How to Get Calcium and Vitamin D * Slideshow: Lactose Intolerance -- 14 Ways to Still Love Dairy * Quiz: Getting Calcium When You’re Lactose Intolerant * Tolerate Lactose Intolerance * Lactose: How Much Can You Take? * Lactose-Free Entree and Snack Recipes * Why Is Almond Milk Good For You? * Lactose Intolerance Topics Today on WebMD