Management of Lactose Intolerance
The primary management of lactose intolerance is dietary modification with reduction or elimination of lactose-containing foods until symptoms resolve, while preserving yogurt and hard cheeses which are generally well-tolerated. 1, 2
Diagnostic Confirmation Before Treatment
Before implementing dietary changes, confirm the diagnosis objectively rather than relying on patient self-report, as self-reported lactose intolerance correlates poorly with actual lactase deficiency 1:
- Hydrogen breath test is the most widely recommended diagnostic method, involving ingestion of 25-50g lactose after overnight fasting with breath samples collected every 15-30 minutes for three hours 1
- A rise in hydrogen concentration >20 parts per million from baseline indicates positive diagnosis 1
- Be aware that false negative rates can reach 25% due to hydrogen non-excretion in approximately 18% of subjects 1
- A 2-week dietary restriction trial with symptom resolution is a simple, economical alternative diagnostic approach 1
- Reserve testing for patients consuming more than 280 ml (0.5 pint) of milk or dairy equivalent daily, as those consuming less typically tolerate moderate amounts even if lactose intolerant 1, 2
Primary Dietary Management Strategy
Foods to Eliminate
- Avoid fresh milk and most dairy products during symptomatic periods 1, 2
- Check for "hidden lactose" in non-dairy products including baked goods, breakfast cereals, drinks, and processed meats 3
Foods That Can Be Retained
- Yogurt and firm/hard cheeses are generally well-tolerated and should NOT be eliminated unnecessarily, as they contain negligible lactose 4, 2
- Hard cheeses contain no lactose or negligible amounts, making them universally tolerable 2
Calcium Preservation Strategy
Complete dairy elimination risks osteopenia and osteoporosis development, so ensure adequate calcium intake through 3, 5:
- Low-lactose or lactose-free milk products
- Bacterially fermented dairy products
- Plant-based milk supplemented with calcium and vitamin D
- Mineral water with calcium
- Certain vegetables high in calcium
Special Clinical Contexts
Secondary Lactose Intolerance
Consider reversible causes that require treatment of the underlying condition 1, 2:
- Celiac disease
- Gastroenteritis
- NSAID use
- Small bowel disease (particularly proximal Crohn's disease) 2
- Chemotherapy-induced bowel mucosal injury (fully reversible after therapy discontinuation) 4, 2
Cancer Patients on Chemotherapy
In patients with diarrhea during chemotherapy, avoid milk and dairy products (except yogurt and firm cheeses) to reduce symptom intensity and duration 4, 2
Infants with Acute Diarrhea
Use lactose-free or lactose-reduced formulas immediately upon rehydration for bottle-fed infants 2
Pharmaceutical Considerations
Do NOT unnecessarily avoid lactose-containing medications, as most people with lactose malabsorption tolerate lactose amounts <12g, and medications rarely contain enough to induce symptoms 4, 2
Broader Differential: FODMAP Intolerance
At least 50% of patients with presumed lactose intolerance actually have broader intolerance to FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) 1, 6:
- If lactose restriction alone doesn't resolve symptoms, consider a low FODMAP diet trial 1, 6
- This is particularly relevant in patients with irritable bowel syndrome 6
- Visceral hypersensitivity can cause symptoms independent of lactose malabsorption 1
Additional Therapeutic Options
Beyond dietary modification, consider 6, 7:
- Exogenous lactase enzyme supplementation for occasional dairy consumption
- Probiotics to induce colon microbiome adaptation
- Consuming milk with food and fiber components, which improves symptom tolerance 8
Critical Pitfall to Avoid
Never rely on patient self-reports alone—objective testing or systematic dietary elimination is essential, as symptom reports are poor predictors of actual lactase deficiency or response to dietary restriction 1, 2