Abdominal discomfort, bloating and diarrhoea are common complaints for many people, often experienced after a hearty meal containing milk or cream. These symptoms may be signs of lactose intolerance, or sensitivity to milk sugar. This is a common digestive problem that makes everyday life difficult for millions of people worldwide. Many are unaware of their condition and attribute the unpleasant symptoms to other causes.
In this article, we explain in detail exactly what lactose intolerance is, how it develops, and what symptoms it involves. We’ll look at the diagnostic methods that can clearly identify the problem and review the available treatment options, ranging from lactase enzyme supplements to dietary changes. Our aim is to provide you with all the information you need to understand and manage this condition effectively. The Endomedix Gastroenterology Centre They provide expert assistance in making a diagnosis and drawing up a personalised treatment plan.
What is lactose intolerance?
Lactose intolerance is a digestive condition that occurs when the body is unable to fully digest lactose, the type of sugar found in milk and dairy products. This inability stems from a lack of, or reduced production of, an enzyme called lactase. The lactase enzyme is produced in the small intestine, and its role is to break down lactose into two simpler sugars, glucose and galactose, which are then easily absorbed into the bloodstream.
If there is an insufficient level of the lactase enzyme, lactose passes undigested into the large intestine. Here, gut bacteria begin to ferment it, leading to the formation of gases (hydrogen, methane), short-chain fatty acids and other by-products. These substances cause the characteristic and unpleasant symptoms of lactose intolerance. It is important to emphasise that lactose intolerance is not the same as a milk allergy, which is an abnormal reaction of the immune system to milk proteins and can cause much more severe, even life-threatening, symptoms.
Types and causes of lactose intolerance
We distinguish between several types based on the severity of the condition and its cause.
Primary lactase deficiency
This is the most common form. The majority of people are born with sufficient levels of the lactase enzyme, which is essential for infant nutrition, as breast milk also contains lactose. After weaning, however, lactase production may gradually decrease. This is a genetically determined process, which occurs to varying degrees among different ethnic groups. In Europe, for example, it is less common among northern populations, whilst it is much more common among southern, Asian and African populations. Symptoms usually appear during adolescence or adulthood.
Secondary lactase deficiency
In this case, the reduction in lactase enzyme production is caused by a disease, injury or surgical procedure affecting the small intestine. Such causes may include, for example:
- Gastroenteritis (inflammation of the stomach and intestines)
- Coeliac disease (gluten sensitivity)
- Crohn's disease
- Surgery involving the small intestine
- Certain medicines or chemotherapy
The good news is that secondary lactase deficiency is often temporary. If the underlying condition is successfully treated and the lining of the small intestine regenerates, lactase production may be restored.
Congenital lactase deficiency
This is an extremely rare, inherited genetic disorder in which the newborn produces no lactase enzyme at all, or only in very small quantities. As a result, the infant is unable to digest even breast milk. The condition causes severe diarrhoea and dehydration within days of birth, and therefore requires immediate feeding with a special lactose-free formula.
Typical symptoms of lactose intolerance
Symptoms usually appear between 30 minutes and 2 hours after consuming a food or drink containing lactose. The severity of the symptoms varies from person to person and depends on the amount of lactose consumed and the degree of lactase deficiency in the individual.
The most common symptoms are:
- Bloating: Gases that build up in the bowels cause a feeling of bloating.
- Stomach ache and cramps: They typically appear in the lower part of the abdomen.
- Diarrhoea: Undigested lactose draws water into the large bowel, resulting in osmotic diarrhoea. The stools are often watery and frothy in consistency.
- Gas formation (flatulence): The release of gases produced by bacteria.
- Nausea, occasional vomiting: A less common symptom.
These symptoms are non-specific, meaning they may also be caused by other digestive disorders, such as irritable bowel syndrome (IBS) or small intestinal bacterial overgrowth (SIBO). It is therefore essential to undergo a specialist examination in order to establish an accurate diagnosis.
Diagnosis of lactose intolerance
If the symptoms suggest lactose intolerance, a gastroenterologist can confirm the diagnosis using a range of different diagnostic methods.
Exhalation test for hydrogen (H2)
This is the most commonly used, reliable and non-invasive diagnostic procedure. During the test, the patient is asked to drink a solution containing a specific amount of lactose. They must then breathe into a special device at regular intervals (usually every 20–30 minutes), which measures the concentration of hydrogen gas in their exhaled breath.
In cases of lactose intolerance, undigested milk sugar reaches the large intestine, where bacteria produce hydrogen gas from it. This gas is absorbed into the bloodstream, travels to the lungs and is then exhaled. If the level of exhaled hydrogen rises above a certain value (usually 20 ppm) compared with the baseline value, the test is positive, confirming lactose malabsorption. The test takes approximately 2–3 hours.
Lactose tolerance test
This test measures changes in blood glucose levels following the consumption of lactose. The patient is asked to drink a lactose solution, and blood samples are taken at specific intervals (usually 30, 60 and 120 minutes) before and after the test. If the body is able to break down the lactose, the absorbed glucose raises blood sugar levels. If blood glucose levels do not rise as expected, this indicates lactose intolerance. It is used less frequently nowadays because it is less specific and more uncomfortable for the patient than the breath test.
Genetic testing
The gene variant responsible for primary lactase deficiency can be detected from a blood sample or a buccal swab. This test reliably indicates a genetic predisposition, but does not provide information on the current extent of lactase deficiency or the severity of symptoms. It is not suitable for detecting secondary lactase deficiency.
Treatment options and medicines
The aim of treating lactose intolerance is to alleviate symptoms and improve quality of life. Although primary lactase deficiency cannot be cured, the symptoms can be effectively managed.
Lactase enzyme replacement preparations
One of the simplest and most common ways of treating lactose intolerance is to use preparations containing the lactase enzyme. These are tablets, capsules or drops available over the counter in pharmacies and chemists, which replace the missing enzyme. The preparation should be taken immediately before or at the same time as consuming a food or drink containing lactose. The enzyme thus begins to break down the lactose in the stomach, preventing the onset of unpleasant symptoms.
These products can be extremely useful if you’re eating out, visiting friends, or simply don’t want to give up your favourite dairy products. The required dose varies from person to person, depending on the amount of lactose consumed and the enzyme content of the product, so it is worth experimenting to find the effective dose.
Dietary management and lifestyle advice
Another key element of treatment is to reduce or eliminate the intake of foods containing lactose. The strictness of the diet depends on the individual’s level of tolerance.
1. Identifying foods containing lactose:
It is important to learn which foods contain lactose. The most obvious sources are milk (cow’s, goat’s and sheep’s milk), cream, sour cream, yoghurt, kefir, quark, cream cheeses and soft cheeses. However, lactose can also be found in hidden forms in a number of processed foods, such as:
- Bakery products, cakes, biscuits
- Sliced meats, sausages
- Salad dressings, sauces, soup powders
- Chocolates, sweets
- Certain medicines and dietary supplements
Always read the list of ingredients on products carefully! Look out for the following words: milk, milk powder, whey, whey powder, lactose.
2. Reducing lactose intake:
Many people with lactose intolerance can consume small amounts of lactose without any problems. It is worth experimenting to find out what amount does not cause symptoms. It often helps to eat foods containing lactose alongside other foods rich in fat or fibre, as this slows down digestion. Mature, hard cheeses (e.g. Parmesan, Cheddar) and butter generally contain very little lactose, so most people can eat them.
3. Lactose-free and plant-based alternatives:
Nowadays, there is a wide range of lactose-free dairy products available, from which the lactose has been removed or pre-digested during production. These are identical in taste and texture to standard products. In addition, there are numerous plant-based alternatives, such as soya, almond, rice, oat or coconut milk, as well as yoghurts and creams made from these.
4. Calcium and vitamin D supplementation:
Dairy products are important sources of calcium and vitamin D. If you significantly reduce or completely stop consuming them, you must ensure that you obtain these nutrients from other sources in order to prevent osteoporosis. Excellent sources of calcium include green leafy vegetables (e.g. spinach, kale), broccoli, almonds, sesame seeds, tofu, and calcium-fortified plant-based milks and fruit juices. If necessary, your doctor may also recommend calcium and vitamin D supplements.
The next steps
Lactose intolerance is a manageable condition which, with the right care and lifestyle changes, need not affect your quality of life. The most important step is an accurate diagnosis, which rules out the possibility of other, more serious digestive disorders. Unpleasant bloating, stomach ache and diarrhoea are not something you simply have to put up with.
If you experience the symptoms described above and suspect that you may be lactose intolerant, do not hesitate to consult a healthcare professional. The Endomedix Gastroenterology Centre Its experienced doctors use modern diagnostic procedures, such as the hydrogen breath test, to help establish an accurate diagnosis. They will then provide personalised advice on diet and the use of lactase enzyme supplements, so that you can once again enjoy your food without any discomfort.
