lactose intolerance can be mild or severe, depending
on how much lactase your body makes. Symptoms usually begin 30 minutes to 2
hours after eating or drinking milk or milk products. If you have lactose
intolerance, your symptoms may include:
Loose stools or diarrhea. Sometimes the
stools are foamy.
Many people think they are lactose-intolerant, because the
symptoms of lactose intolerance are very common symptoms. If you feel sick
after drinking a glass of milk one time, you probably do not have lactose
intolerance. But if you feel sick every time you have milk, ice cream, or
another dairy product, you may have lactose intolerance.
Sometimes people who have never had problems with milk or dairy products
suddenly have lactose intolerance. This is more common as you get older.
Symptoms of the most common type of lactose intolerance—adult
lactose intolerance—often start during the teen or adult years and continue
for life. Symptoms of acquired lactose intolerance last as long as the small
intestine does not make lactase.
In rare cases, newborns are
lactose-intolerant. Symptoms in newborns include severe foamy diarrhea, diaper
dehydration, weakness and irritability, and slow
Lactose intolerance is not the same thing as a food allergy to milk. Symptoms of a milk allergy are usually more severe than those from lactose intolerance. People who have a milk allergy cannot eat or drink any milk products. For more information, see the topic Food Allergies.
If you think you might have lactose intolerance, talk
it over with your doctor. Your doctor can make sure that your symptoms are
caused by lactose intolerance and not by another problem. Other conditions can
cause symptoms similar to those of lactose intolerance, including
irritable bowel syndrome,
inflammatory bowel disease, overuse of laxatives, and
problems digesting foods that contain
fructose and sorbitol.