Lactose Intolerance
Also known as: Lactase Deficiency, Dairy Intolerance
Lactose intolerance is a common digestive condition in which the body cannot fully digest lactose, the sugar in milk and dairy, due to lactase enzyme deficiency. Undigested lactose causes gas, bloating, and diarrhea. It is distinct from milk allergy, which is an immune-mediated and potentially life-threatening condition.
Symptoms
Causes
- Primary lactase deficiency (genetically programmed decline after weaning — most common)
- Secondary lactase deficiency from small intestine injury (celiac, Crohn's, gastroenteritis)
- Congenital lactase deficiency (rare genetic condition)
- Developmental lactase deficiency in premature infants
Risk Factors
- African, Asian, Hispanic, and Native American descent
- Increasing age
- Premature birth
- Diseases affecting the small intestine
Diagnosis
- Hydrogen breath test (gold standard)
- Lactose tolerance blood test
- Elimination diet trial
- Genetic testing for lactase persistence gene
Treatment
- Dietary lactose reduction
- Lactase enzyme supplements taken with dairy meals
- Lactose-free dairy products
- Calcium and vitamin D supplementation if dairy is significantly reduced
- Gradual reintroduction to determine personal tolerance level
Prevention
- Primary lactose intolerance cannot be prevented
- Secondary forms may be prevented by treating underlying intestinal conditions
- Lactase supplements can prevent symptoms before consuming dairy
When to See a Doctor
- Digestive symptoms consistently occur after consuming dairy
- You need help determining if symptoms are lactose intolerance or another condition
- Concerned about calcium and vitamin D intake
- A child has persistent diarrhea or poor growth related to dairy
Frequently Asked Questions
Related Conditions
Related from the Supplement Library
Probiotics (Lactobacillus)
StrongProbiotic · Gut microbiome balance and diversity
Digestive Enzymes
ModerateCompound · Improved protein, fat, and carbohydrate digestion
Calcium
StrongMineral · Bone and dental health (99% of body calcium)
Vitamin D
StrongVitamin · Bone health and calcium absorption
L-Glutamine
ModerateAmino Acid · Gut lining repair and intestinal integrity
These supplements have been studied in relation to Lactose Intolerance. Always consult your healthcare provider before starting any supplement, especially if you take medications.
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