Lactose Intolerance

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Basics

• Summary
• Start Here
• Diagnosis and Tests

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• Related Issues
• Genetics

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Research

• Clinical Trials
• Journal Articles

Resources

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• Patient Handouts

Summary

Lactose intolerance means that you cannot digest foods with lactose in them. Lactose is the sugar found in milk and foods made with milk. After eating foods with lactose in them, you may feel sick to your stomach. You may also have

• Gas
• Diarrhea
• Swelling in your stomach

Your doctor may do a blood, breath or stool test to find out if your problems are due to lactose intolerance.

Lactose intolerance is not serious. Eating less food with lactose, or using pills or drops to help you digest lactose usually helps. You may need to take a calcium supplement if you don't get enough of it from your diet, since milk and foods made with milk are the most common source of calcium for most people.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

Start Here

• Lactose Intolerance (Mayo Foundation for Medical Education and Research)
• Lactose Intolerance (National Institute of Diabetes and Digestive and Kidney Diseases) Also in Spanish
• Problems Digesting Dairy Products? (Food and Drug Administration)

Diagnosis and Tests

• Lactose Tolerance Tests (American Association for Clinical Chemistry)

Related Issues

• Dairy Dilemma: Are You Getting Enough Calcium? (National Institutes of Health)
• Food Intolerance vs. Food Allergy: What's the Difference? (Mayo Foundation for Medical Education and Research) Also in Spanish
• Milk Allergy (Mayo Foundation for Medical Education and Research)
• What FDA Learned About Dark Chocolate and Milk Allergies (Food and Drug Administration) Also in Spanish
• What People with Lactose Intolerance Need to Know about Osteoporosis (National Institute of Arthritis and Musculoskeletal and Skin Diseases)

Genetics

• Genetics Home Reference: lactose intolerance (National Library of Medicine)

Clinical Trials

• ClinicalTrials.gov: Lactose Intolerance (National Institutes of Health)

Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)

• Article: World-wide distributions of lactase persistence alleles and the complex effects...
• Article: Peroxisome proliferator-activated receptor gamma (PPARγ) regulates lactase expression and activity...
• Article: Medicines, excipients, and dietary intolerances.
• Lactose Intolerance -- see more articles

Find an Expert

• National Institute of Diabetes and Digestive and Kidney Diseases

Children

• Lactose Intolerance (For Kids) (Nemours Foundation)
• Lactose Intolerance (For Parents) (Nemours Foundation) Also in Spanish

Teenagers

• Lactose Intolerance (For Teens) (Nemours Foundation)
• Lactose Intolerance: A Guide for Teens (Children's Hospital Boston) Also in Spanish

Patient Handouts

• Lactose intolerance (Medical Encyclopedia) Also in Spanish
• Lactose Intolerance (National Institute of Diabetes and Digestive and Kidney Diseases) - PDF