Bloating, stomach cramps and unpleasant diarrhoea are symptoms familiar to many people after a hearty lunch containing milk and sour cream. Although these complaints are extremely common, many people are unaware that they may be caused by an underlying digestive problem: lactose intolerance. This condition affects millions of people worldwide, yet there are numerous misconceptions surrounding it, which make it difficult to diagnose correctly and treat effectively.
In this article, we take an in-depth look at the topic of lactose intolerance. Our aim is to set the record straight, dispel the most common misconceptions, and present the modern diagnostic and treatment options that enable patients to lead a full and healthy life. We will look at exactly what happens in the body in cases of lactose intolerance, how it can be reliably diagnosed, and what steps can be taken to alleviate the symptoms. The Endomedix Gastroenterology Centre With the help of our experts, we also provide practical advice to make your day-to-day life easier.
What exactly is lactose intolerance?
Lactose intolerance, also known as milk sugar intolerance, is a digestive disorder that occurs when the body is unable to digest lactose properly. Lactose is a type of sugar (a disaccharide) found in milk and most dairy products.
A special enzyme, lactase, is required to digest it. This enzyme is produced by the cells of the small intestine’s mucous membrane. The role of lactase is to break down lactose into two simpler sugar molecules (glucose and galactose) that the body can absorb. If there is not enough lactase in the body, the lactose passes undigested into the large intestine. There, the gut bacteria begin to ferment it. The by-products of this process are various gases (hydrogen, carbon dioxide, methane) and short-chain fatty acids, which cause the characteristic symptoms.
It is important to distinguish between lactose intolerance and milk protein allergy. Whilst lactose intolerance is a digestive problem, a milk allergy is an abnormal reaction of the immune system to the proteins found in milk (e.g. casein or whey protein). The symptoms of a milk allergy can be much more severe and may even cause life-threatening anaphylactic shock.
Types of lactose intolerance
We distinguish between three main types, each of which arises for different reasons.
- Primary lactase deficiency: This is the most common form. It has genetic causes and means that the production of the lactase enzyme gradually decreases as a person gets older, following infancy. This is a natural process that affects a significant proportion of the human population, although its prevalence varies by geographical region. In Europe, for example, it is less common amongst northern populations, whilst it is almost universal in southern countries, as well as in Asia and Africa.
- Secondary lactase deficiency: In this case, lactase deficiency develops as a result of another disease or condition affecting the small intestine. Such underlying causes may include, for example, Crohn’s disease, coeliac disease (gluten sensitivity), a severe intestinal infection (gastroenteritis), chemotherapy or surgery affecting the small intestine. The good news is that if the underlying condition is successfully treated, lactase production may be restored.
- Congenital lactase deficiency: This is an extremely rare, hereditary genetic disorder in which the baby produces no lactase enzyme at all, or only minimal amounts, from birth. As a result, the baby is unable to digest breast milk, which leads to immediate and severe symptoms. The condition can be managed with a special, lactose-free formula.
The most common symptoms of lactose intolerance
The severity of symptoms varies from person to person. It depends on the amount of lactose consumed and the individual’s level of sensitivity – in other words, how much lactase enzyme the body still produces. Symptoms typically appear between 30 minutes and 2 hours after consuming a food or drink containing lactose.
The most common clinical symptoms are as follows:
- Abdominal pain and cramps: Gas and fluid accumulating in the bowel put pressure on the bowel wall, causing pain.
- Bloating, abdominal distension: It is caused by the gases (hydrogen, methane) produced during bacterial fermentation.
- Increased intestinal gas formation (flatulence): This, too, is a direct consequence of gas production.
- Diarrhoea: Due to the osmotic effect of undigested lactose, water is drawn into the bowel, which makes the stools looser and speeds up bowel movements. The stools may be characteristically watery, frothy and have a sour smell.
- Nausea and occasional vomiting: This can occur particularly after consuming larger amounts of lactose.
- Gurgling, rumbling bowel sounds (borborygmus): It is caused by the movement of fluid and gases that have accumulated in the bowel.
These symptoms may overlap with those of other digestive disorders, such as irritable bowel syndrome (IBS) or small intestinal bacterial overgrowth (SIBO). This is why it is crucial to establish an accurate diagnosis, for which the assistance of a specialist gastroenterologist is essential.
Diagnostic methods: How can we be sure?
As the symptoms are non-specific, any suspicion of lactose intolerance must be confirmed by objective diagnostic methods. The Endomedix Gastroenterology Centre uses the most advanced and reliable methods.
Exhalation test for hydrogen (H2):
This test is the „gold standard” for diagnosing lactose intolerance. The patient must drink a water-based solution containing a specific amount of lactose. They must then breathe into a special device at specified intervals (usually every 20–30 minutes, for 2–3 hours). The device measures the hydrogen concentration in the exhaled air.
If the body is unable to break down lactose, it passes into the large intestine, where bacteria produce hydrogen gas from it. This gas is absorbed into the bloodstream, reaches the lungs and is exhaled. If the hydrogen level rises above a certain value (typically 20 ppm) compared with the baseline value, the test is positive, indicating lactose intolerance. The test is painless and safe.
Genetic testing:
This method involves a simple buccal swab or blood sample. It investigates the genetic basis of primary (adult-onset) lactase deficiency. It looks for a point mutation in a neighbouring regulatory region (the MCM6 gene) of the gene (LCT) that regulates the production of the lactase enzyme. In Europe, testing for the C/T-13910 polymorphism is the most common.
- C/C genotype: In this case, lactase production decreases with age, meaning that the individual is lactose intolerant.
- C/T or T/T genotype: These genotypes indicate lactase persistence, that is, the ability to produce the lactase enzyme in adulthood. Such individuals are not lactose intolerant.
It is important to note that the genetic test only provides a result for the primary, genetically determined form. It does not detect secondary lactose intolerance, as this is not caused by a genetic factor but by another medical condition.
Facts and myths about lactose intolerance
There is a great deal of misinformation circulating about this condition, which can lead to misunderstandings and unnecessary anxiety. Let’s take a look at the most common ones!
Misconception: Lactose intolerance is the same as a milk allergy.
Fact: As mentioned earlier, the two are completely different conditions. Lactose intolerance is a digestive disorder (enzyme deficiency), whilst a milk allergy is an immune reaction to milk protein. A milk allergy is more serious and can cause symptoms that are even life-threatening.
Misconception: Anyone who is lactose intolerant must completely eliminate all dairy products from their diet.
Fact: This is not true for most people. Individual tolerance levels vary. Many people can consume small amounts of lactose without experiencing any symptoms. Furthermore, many dairy products are naturally low in lactose. In mature cheeses (e.g. Parmesan, Cheddar), most of the lactose is broken down during the maturing process. Fermented products, such as yoghurt or kefir, contain bacterial cultures that aid the digestion of lactose, so these are often better tolerated by those affected.
Misconception: Lactose-free products do not contain milk.
Fact: Lactose-free products (milk, yoghurt, quark, etc.) are made from cow’s milk in exactly the same way as their conventional counterparts. The difference is that during production, the enzyme lactase is added to them, which breaks down the milk sugar in advance. Therefore, people with a milk protein allergy must not consume these products!
Misconception: Lactose intolerance can be treated.
Fact: Primary, genetically determined lactose intolerance is currently incurable, as we are unable to „reactivate” the production of the lactase enzyme. However, the condition can be managed very effectively through diet and enzyme supplements. In the case of secondary lactose intolerance, however, lactase production may be restored once the underlying condition has been resolved.
Modern treatment options and lifestyle advice
The basis of treating lactose intolerance is preventing symptoms and ensuring an adequate intake of nutrients. The Endomedix Gastroenterology Centre Its specialists and dietitians draw up a personalised treatment plan for each patient.
1. Dietary changes
The cornerstone of the treatment is reducing lactose intake in line with the individual’s tolerance level.
- Elimination diet: Following diagnosis, it is advisable to completely eliminate lactose from your diet for a short period (around two weeks) to allow the symptoms to subside.
- Back to: After this, foods with varying lactose content can be gradually reintroduced in small quantities so that the patient can determine their own tolerance threshold. It may be helpful to keep a food diary.
- Consumption of lactose-free products: Nowadays, there is a wide range of lactose-free milks, yoghurts, cheeses, spreads and other products available, which offer a fully-fledged alternative.
- Plant-based alternatives: Almond, soya, rice or oat milks can also be good alternatives, but it is important to check their nutritional value (protein and calcium content).
2. Lactase enzyme supplementation
Lactase enzyme preparations (available in tablet, drop or capsule form) sold in pharmacies and chemists’ are an extremely practical solution. These should be taken immediately before a meal containing lactose. The enzyme helps break down lactose in the gut, thereby preventing symptoms. This can be particularly useful when eating out or in situations where you are unsure of the lactose content of a meal.
3. Calcium and vitamin D supplementation
As dairy products are the main sources of calcium in our diet, people who are lactose-intolerant are at risk of calcium deficiency and, consequently, osteoporosis. It is therefore particularly important to ensure an adequate intake of calcium from other sources.
- Foods rich in calcium: broccoli, kale, spinach, sardines (with bones), almonds, sesame seeds, tofu, calcium-enriched plant-based milks and orange juice.
- Dietary supplements: If necessary, taking calcium and vitamin D supplements may also be advisable on medical advice. Vitamin D is essential for the absorption of calcium.
When should we see a doctor?
If you experience symptoms typical of lactose intolerance, it is strongly recommended that you consult a gastroenterologist. This is particularly important if your symptoms are severe, persistent, or if you notice warning signs such as unintentional weight loss, blood in the stools, night-time diarrhoea or iron-deficiency anaemia. These symptoms may, in fact, indicate a more serious condition.
An accurate diagnosis is essential for initiating the appropriate treatment and for ruling out other conditions that cause similar symptoms (e.g. IBS, coeliac disease, inflammatory bowel diseases). The Endomedix Gastroenterology Centre Its highly qualified specialists use modern diagnostic tools and provide personalised advice to help patients lead symptom-free, fulfilling lives. Don’t let unpleasant symptoms dictate your daily life! With the right expert help, lactose intolerance is a condition that can be effectively managed and does not limit your ability to enjoy life.
