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Diarrhea and Lactose Intolerance: When Dairy Is the Problem

Milk may do a body good, but not if you’re one of 30 million to 50 million people who suffers from lactose intolerance. Lactose intolerance results from an inability to digest the natural sugar (lactose) found in milk and milk products. Lactose intolerance symptoms can include bloating, diarrhea, gas, and cramping. But there are ways to manage lactose intolerance while reaping the nutritional benefits of dairy products.

What Causes Lactose Intolerance?

Lactose is the natural sugar found in milk and dairy products. Lactase, an enzyme in the small intestine, is needed to break down the sugars for full digestion and absorption into the body. If you don’t have enough of the enzyme, you may get diarrhea and upset stomach when you eat or drink dairy products – although not everyone with a lactase deficiency has lactose intolerance symptoms. You may experience mild, moderate, or severe symptoms, depending on how much lactase your body produces.

Most people develop low lactase levels during mid-childhood (around age 5). In some people, low levels continue into adulthood.

Lactase deficiency can also be caused by:

  • Genetics: Although rare, some people may be born with a gene mutation that prevents them from producing lactase. Affected babies usually have diarrhea from birth.
  • Premature birth: Premature babies may not produce enough lactase at first. In these cases, the amount of lactase produced increases with time.
  • Other health conditions: Certain diseases, such as celiac disease, inflammatory bowel syndrome, cystic fibrosis, and Crohn’s disease, as well as injuries to the small intestine, can lead to a reduction in the production of lactase.

Lactose intolerance is less likely to affect people of northern European descent. Those most likely to experience lactose intolerance symptoms include:

  • African-Americans: They are up to 80% more likely to be lactose intolerant that others.
  • Asian-Americans: They are 90%-100% more likely to be lactose intolerant.
  • Native Americans: They are 80%-100% percent more likely to be lactose intolerant.

How Can I Control Lactose Intolerance Symptoms?

If you are lactose intolerant, you may experience mild to severe symptoms, including diarrhea, between 30 minutes to two hours after eating or drinking dairy products. Other symptoms may include nausea, bloating, stomach cramps, and gas.

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