Cow's milk problems

Lactose Intolerance or Milk Allergy? How to Tell the Difference

Milk can cause digestive problems for some people, but the underlying cause may vary. The most common issues are either lactose intolerance or a cow's milk protein allergy. Although these terms are often confused, they refer to two very different mechanisms.

🥛 What is lactose and why can it cause problems?

Lactose is a milk sugar found in both human and animal milk (cow, goat, sheep). To digest it properly, our body needs an enzyme called lactase, which breaks it down in the small intestine.

After birth, we all have high levels of this enzyme – which makes sense, since milk is our first food. But in most mammals, the ability to digest lactose decreases after weaning. In humans too, lactase production can drop by up to 90% during the first four years of life.

Nevertheless, we are the only species that continues to consume milk into adulthood – and not every body can handle it.

❗ What is lactose intolerance?

It is the inability to break down lactose due to a lack of the enzyme lactase. As a result, undigested lactose reaches the large intestine, where it's fermented by bacteria – causing various unpleasant symptoms.

📊 In Central Europe, about 15–20% of people suffer from lactose intolerance. In Scandinavia, it's rare (around 2%), while in southern Europe (e.g., Sicily), the rate is as high as 70%.

🔍 How does lactose intolerance present itself?

Symptoms depend on several factors:

• Amount of lactose consumed

• Type of food (fermented dairy is better tolerated than plain milk)

• Speed of digestion

• Composition of gut microbiota

• Residual lactase activity

🧠 Everyone has a different tolerance level – some can manage a small piece of cheese, others cannot. Symptoms may include:

• Abdominal pain

• Cramping, bloating

• Diarrhea, sometimes sour-smelling and frothy

• Nausea, occasionally vomiting

• In children: food refusal, weight loss, poor growth

🧪 How is lactose intolerance diagnosed?

The most accurate tests include:

• Biopsy of the small intestinal lining – directly determines the level of lactase (performed during endoscopy) – complex, invasive, expensive, requires hospitalization, and is not used in children when lactose intolerance is suspected.

• Lactose tolerance test or hydrogen breath test – suitable for children who can cooperate, but in my opinion unnecessarily complicated and available only through certain specialists (typically an immunologist or allergist).

• ✅ Elimination-exposure test (gold standard) – involves removing lactose from the diet for 2 weeks (the child consumes only lactose-free milk, butter, yogurt). If symptoms disappear and return after reintroducing dairy products, lactose intolerance is very likely.

❌ Lactose intolerance is not an immune response, so it cannot be confirmed by blood antibody tests.

⚠️ Some commercial labs offer IgA or IgG antibody tests for lactose – these results are not meaningful and may be misleading.

🍽️ What to do if lactose intolerance is confirmed?

• Avoid or limit dairy products (plain milk is most problematic)

• Try lactose-free alternatives, which are widely available

• Lactase enzyme tablets before meals can also help

🧬 Milk Allergy – What's the Difference?

Unlike intolerance, this is an immune reaction to cow's milk protein, not lactose.

👶 Most common in children under 1 year old; becomes rare with age.

🧠 Even small amounts of milk can trigger an allergic reaction – often affecting multiple systems:

• Skin (eczema, rashes)

• Digestive system (diarrhea, vomiting)

• Respiratory tract (runny nose, cough, wheezing)

• Poor growth overall

🩸 Diagnosis:

• Blood test for specific IgE antibodies

• Elimination-exposure test is also used for confirmation

⚠️ With allergy, avoiding lactose isn't enough – all forms of milk protein must be avoided. Lactose-free products are still unsuitable, as they still contain the protein that causes the reaction.

🏡 A Simple Test You Can Do at Home

If you suspect a milk-related problem, whether intolerance or allergy (especially in young children), try the elimination-exposure test:

1. Avoid all dairy products for 2 weeks (for allergy, also exclude lactose-free ones!)

2. Observe for improvement.

3. After 2 weeks, reintroduce dairy products.

4. If symptoms return, the diagnosis is very likely.

In most cases, complex and expensive testing is not necessary.