![Woman with lactose intolerance holding a glass of milk in one hand and making a](https://images.medicinenet.com/images/article/main_image/how-do-i-know-if-i-am-lactose-intolerant-or-allergic-to-milk.jpg?output-quality=75)
Lactose intolerance is a condition in which the body does not produce enough of the enzyme lactase to break down the sugars in dairy products (lactose).
Lactose intolerance is not a food allergy, in which the body’s immune system reacts to the protein in dairy products, rather than the sugars.
It is possible to become lactose intolerant all of a sudden due to:
- Injury to the small intestine (secondary lactose intolerance)
- Infections, diseases, or other conditions that injure the small intestine
- Inflammatory bowel disease (IBD)
- Crohn’s disease
- Ulcerative colitis
- Celiac disease
- Diabetic enteropathy
- Human immunodeficiency virus (HIV) enteropathy
- Inflammatory bowel disease (IBD)
- Infections, diseases, or other conditions that injure the small intestine
- Certain treatments
- Some medicines
- Chemotherapy
- Surgery
- Radiation therapy
- Prolonged abstinence from dairy triggers
- Aging: tolerance to lactose normally decreases with age
Other causes of an inability to produce adequate lactase include:
- Certain genetic conditions
- Lactase nonpersistence (also called primary lactase deficiency), the most common cause of low lactase levels
- Congenital lactase deficiency, starts at birth (rare)
- Premature birth
What Are Symptoms of Lactose Intolerance?
Symptoms of lactose intolerance occur only after eating foods that contain dairy and can include:
How Is Lactose Intolerance Diagnosed?
Lactose intolerance is diagnosed with a patient history and physical examination along with tests such as:
- Lactose hydrogen breath test
- Lactose tolerance test
What Is the Treatment for Lactose Intolerance?
Treatment for lactose intolerance includes:
- Limiting or avoiding dairy products
- Enzyme supplementation to help break down the lactose in dairy foods
- Lactaid (tablets or liquid), Lactrase, LactAce, Dairy Ease, and Lactrol
- Enzyme supplements should be taken right before eating
- Supplements may be taken during a meal, but might not work as well
- These products can’t always break down all the lactose so symptoms may still occur even when a supplement is used
- Talk to your doctor before using enzyme supplements
- They may not be recommended for some people, such as children and pregnant or breastfeeding women
- Lactaid (tablets or liquid), Lactrase, LactAce, Dairy Ease, and Lactrol
- Supplementing nutrients such as calcium, vitamin D, and protein with non-dairy sources
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https://www.uptodate.com/contents/lactose-intolerance-the-basics?search=Lactose%20Intolerance&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2
https://www.niddk.nih.gov/health-information/digestive-diseases/lactose-intolerance