What is Lactose Intolerance?

Lactose intolerance is a common digestive disorder where the body struggles to digest lactose, the natural sugar found in milk and dairy products. This occurs when the small intestine does not produce enough lactase, the enzyme needed to break down lactose into simpler sugars (glucose and galactose) for absorption. Without sufficient lactase, undigested lactose passes into the large intestine, where bacteria ferment it, causing uncomfortable symptoms.

Types of Lactose Intolerance:

Primary Lactose Intolerance: The most common form, where lactase production naturally decreases after childhood, typically in adulthood. It is more prevalent in certain ethnic groups, such as Africans, Asians, Hispanics, or Native Americans.
Secondary Lactose Intolerance: Caused by illness, injury, or surgery affecting the small intestine, such as celiac disease, Crohn’s disease, or infections. Treating the underlying condition may restore lactase levels.
Congenital or Developmental Lactose Intolerance: Rare, present from birth due to genetic factors or in premature infants due to an immature gut.

While generally harmless, lactose intolerance can impact quality of life and nutrient intake, such as calcium and vitamin D. Risk factors include age, ethnicity, premature birth, small intestine diseases, and certain cancer treatments.

Lactose Intolerance Symptoms

Symptoms typically appear 30 minutes to two hours after consuming dairy and vary in severity. They include:

Bloating
Diarrhoea
Gas
Nausea, sometimes with vomiting
Abdominal cramps or pain

These symptoms arise from the fermentation of undigested lactose in the large intestine. Not everyone reacts with the same intensity; some tolerate small amounts of lactose, while others experience severe symptoms. If you consistently notice these symptoms after consuming dairy, consult a doctor to rule out other conditions.

Lactose Intolerance Diet

Managing lactose intolerance involves dietary adjustments to reduce or eliminate lactose while maintaining a balanced diet. Most people don’t need to completely avoid dairy, as small amounts or specific types may be tolerated.

Foods to Avoid or Limit:

Milk (cow, goat, sheep)
Ice cream, soft cheeses (e.g., ricotta, cottage)
Cream, buttermilk, whey-based products
Processed foods like baked goods, cereals, soups, margarine, and salads containing dairy

Foods You Can Eat:

Lactose-free milk, yogurt, and ice cream
Hard cheeses (e.g., cheddar, Swiss) with minimal lactose
Plant-based milks (e.g., almond, soy, oat—check for added sugars)
Non-dairy calcium sources: broccoli, leafy greens, fortified juices, canned salmon, almonds, oranges, dried beans
Fruits, nuts, plain potato chips, oat/rice cakes, dark chocolate, lactose-free spreads

Dietary Tips for Low-Lactose Eating:

Consume dairy with meals to slow digestion.
Use lactase enzyme supplements before eating dairy.
Experiment to find your tolerance level—many can handle up to 120 ml of milk at a time.

Consult a dietitian for a personalized plan to ensure adequate nutrient intake.

lactose intolerance foods dairy cheese yogurt

Lactose Intolerance Treatment

There is no cure for lactose intolerance, but it can be managed through lifestyle changes, primarily by reducing lactose intake. Treatment options include:

Lactase Enzyme Supplements: Products like Lactaid tablets or drops break down lactose.
Probiotics: Found in some yogurts or supplements, they may aid digestion, though results vary.
Treating Underlying Causes: For secondary lactose intolerance, addressing conditions like celiac disease may improve symptoms.

In rare, severe cases, a completely lactose-free diet may be necessary. Consult a doctor for personalized advice.

Lactose Intolerance FAQs

Does lactose intolerance go away? Primary lactose intolerance is usually permanent, but secondary forms may improve with treatment of the underlying cause.
How do I know if I have lactose intolerance? Track symptoms after consuming dairy and consult a doctor for tests like the hydrogen breath test.
Is lactose intolerance hereditary? Yes, primary lactose intolerance often has a genetic basis and is more common in certain ethnic groups.
Can I eat dairy if I’m lactose intolerant? Many tolerate small amounts or lactose-free products with enzyme supplements.
Should I avoid all dairy during pregnancy if lactose intolerant? Not necessarily; opt for lactose-free options or small portions and consult a doctor.
Can children have lactose intolerance? It’s less common in young children but can occur, especially if congenital or due to illness.

Useful Links: National Institutes of Health (NIH) International Foundation for Gastrointestinal Disorders

Lactose Intolerance Test

Diagnosis begins with discussing symptoms, medical history, and diet with a doctor. A simple elimination test—avoiding dairy for a short period and monitoring symptoms—can provide clues. The hydrogen breath test is commonly used, where you drink a lactose-rich liquid, and hydrogen levels in your breath are measured. High hydrogen levels indicate poor lactose digestion.

Genetic Testing for Lactose Intolerance

Genetic testing detects the C13910T and G22018A polymorphisms in the MCM6 gene, which regulates the LCT gene responsible for lactase production.

Advantages of Genetic Testing:

- Accuracy: Provides clear results for the presence of polymorphisms.
- Non-Invasive: No need to consume lactose, unlike breath or blood tests.
- Definitive: Confirms genetic predisposition to lactose intolerance.