Lactose intolerance

This is one of the most common food intolerances

Like many mammals, many people lose the ability to break down lactose (milk sugar) in the small intestine throughout the course of life. In this sense, it is therefore not a real disease but a normal development for most people. Seventy-five percent of the world’s population have a lactose intolerance with more than 90% in Asia. However, due to the high consumption of dairy products in our culture, many people suffer from symptoms such as bloating, diarrhoea or abdominal pain. One can distinguish between the genetic form of lactose intolerance (blood test determination), the so-called primary lactose intolerance, and an acquired form known as secondary lactose intolerance (e.g. can occur in the presence of infections, coeliac disease, etc.).

Depending on the severity of the intolerance, the enzyme (lactase) which cleaves lactose in the villi of the small intestine is reduced or completely absent. The milk sugar (lactose) then passes undigested into the large intestine where it is fermented. This can lead to gas and the uptake of water in the intestines, which can cause bloating, diarrhoea and stomach pain. However, there are other non-specific symptoms such as chronic fatigue, depression, body aches, anxiety, dizziness, sweating, headache, nervousness, insomnia, acne, poor concentration, and the impaired absorption of minerals, trace elements and vitamins.


Tests for lactose intolerance

The genetic form of lactose intolerance can be diagnosed by a blood test (NB: this test is not covered by health insurance!). If the test is positive, no further tests need to be carried out. Primary lactose intolerance is the diagnosis.

A breath test can show whether the hydrogen content of exhaled air rises after ingesting 25 g lactose (milk sugar); this would prove a lactose intolerance and more specifically,  a secondary lactose intolerance). We perform this test in our practice. This test requires you to fast for a minimum of 12 hours prior to the test, which takes approximately 2-3 hours.

There is also a test of lactase activity from biopsies of the small intestine that can be taken during a gastroscopy. This test is very accurate.

The simple omission of lactose-containing foods for a period of time is also a possible test, but has the least significance.

If the existence of lactose intolerance is proven, but is associated with a lack of symptoms during the consumption of lactose-containing products, this is known as lactose malabsorption.



If you are tested positive for lactose intolerance, it is important to understand that this is not a serious illness. There are no long-term consequences for the gastrointestinal system (in contrast to the effects of coeliac disease). It may be useful to exclude the causes of a possible secondary lactose intolerance (for example, due to coeliac disease or an infection). The treatment possibilities involve the reduction of lactose products or switching to lactose-free products and/or the use of enzymes (e.g. Lacdigest) prior to consuming a lactose-containing meal.


Diet for lactose intolerance

Depending on the severity of symptoms, a lactose intolerance can be successfully treated by a lactose-free or low lactose diet. A lactose intolerance without discomfort (lactose malabsorption) does not necessarily have a treatment or diet.

A lactose-free diet should contain < 1 g lactose per day, and a low-lactose diet: 8-10 g lactose per day.

On average, healthy adults consume about 20-30 grams of lactose daily, mainly through milk and dairy products. When on a lactose-free or low lactose diet, it is important to entirely or partially avoid these foods. The requirement of calcium must be met by targeted food selection, but can be sufficiently covered by lactose-free milk and cheeses in general.

Lactose content of selected foods (4 groups):

1. Lactose-free

All foods that contain no milk and dairy products are lactose free. These include for example:

Eggs, meat, fish, ham, roast beef, sausage, potatoes, rice, polenta, all cereals, bread and biscuits without milk, rusk crackers, pasta, vegetables, fruits, fruit and vegetable juices, fruit syrups, jams, honey, sugar, soy products such as: soy milk, soy milk desserts, soy yogurt, tofu, etc.

As a substitute for conventional milk, lactose-free rice milk, coconut milk, oat milk, vegetable milk powder can be used.

2. Low lactose foods (under 1 g lactose/100 g)

Butter, clarified butter, all hard and sliced cheeses and almost all soft cheeses. During the maturation process, the largest proportion of lactose disappears.

Examples of food with a lactose content of less than 1 g/100 g:

  • butter 0.6 g
  • camembert (45% fat [dry matter]) 0,1 g
  • ricotta 0.3 g
  • brie 0.1 g
  • feta (from sheep milk) (45% fat [dry matter]) 0.5 g
  • parmesan 0.06 g
  • cheddar (50% fat [dry matter]) 0.3 g
  • Emmentaler, Tilsiter, pizza cheese, mountain and farm cheeses, Edam, Gorgonzola 0-1 g
  • mozzarella 0.5-1.5 g

3. Lactose containing foods (1.0 - 4.5 g lactose/100 g)

Small amounts of yogurt, buttermilk or sour milk and kefir, which are among the acidified milk products (e.g. 100 mL/day), are still tolerated in mild lactose intolerance because the lactose is broken down partially by the added lactic acid bacteria. The lactose content is, therefore, lower in older, more mature yogurts.

Examples of foods with a lactose content of 1 - 4.5 g/100 g

  • Yoghurt 3.5% fat 4.1 g
  • nougat nut creme (Nutella) 1.9 g
  • fruit yoghurt with varied fat content 3.1 g
  • sour milk 4.0 g
  • butter milk 4.0 g
  • creme fraiche 2.4 g
  • sour cream 15% fat 4.0 g
  • cream cheese 50% fat [dry matter] 3.4 g
  • cottage cheese 3.3 g
  • coffee cream 10% fat 4.0 g
  • goat milk 4.2 g

4. Foods with a high lactose content (over 4.5 g lactose/100 g)

Milk (cow, goat, sheep, horse), whey, drinking cocoa, condensed milk, coffee cream as well as flour-based and sweet desserts, foods prepared with milk (e.g. milk rice, sweet casseroles, puddings) are rich in lactose.

Examples of foods with a lactose content of over 4.5 g/100 g

  • whey powder 70.0 g
  • ice cream (on average) 6.7 g
  • skimmed milk powder 50.5 g
  • skimmed milk 4.8 g
  • full cream milk powder 35.1 g
  • milk chocolate 9.5 g
  • full cream milk 3.5% fat 4.6 g
  • condensed milk 7.5% fat 9.3 g
  • milk (sheep) 4.6 g
  • low-fat yoghurt 5.2 g

Processed food which often contain lactose

  • ready-made meals (e.g. creamed spinach, creamed vegetables, dairy ice cream, etc.)
  • frozen meals; prepared mashed potatoes, processed puddings, processed dumplings (potato), packet soups, etc.
  • instant sauces, salad and grill sauces, mayonnaises, conventional margarines
  • pastries, cakes, waffles, toast, some milk breads
  • sausage and meat spreads, often found in low-fat sausages
  • instant cacao such as Ovomaltine®, Nesquick®, etc.

Nutritional tips for lactose intolerance

After the diagnosis, a 4-week exclusion period of all lactose products (i.e. lactose-free diet) can be undertaken. With this process, the individual tolerance of different products can be tested. We can arrange for you to begin this diet with the help of a dietician. For the preparation of soups, sauces and muesli, lactose-free milk or soy milk products should be used. Packaged foods should be carefully checked for their lactose content as it is often normal in the food industry to add lactose. Adequate calcium intake is usually not a problem because of the possibility to eat certain cheeses and drink lactose-free milk. Other foods that are rich in calcium such as broccoli, fennel, cabbage, swedes, celery, leeks, etc. (calcium-rich vegetables), raspberries, blackberries, kiwi, figs, oranges, etc. (calcium-rich fruits), calcium-rich mineral water, and calcium-fortified products can additionally be taken into account in your diet.

Lactose preparations

These preparations contain pure lactase, the enzyme able to split lactose into the monosaccharides, glucose and galactose. There are various preparations with similar and adequate effects (i.e. Lacdigest, Lactrase, lactase, etc.). In this case, the capsule form acts best and should be taken when considering a lactose-rich meal.

Do not hesitate to contact us if you have any further questions.