Nature and incidence of the disease
Lactose intolerance, or hypolactasia, is caused by the human body’s inability to produce enough lactase, the enzyme that breaks down milk sugar, or lactose.
Lactose is a disaccharide that cannot be absorbed through the wall of the small intestine, so it must first be broken down into two simple sugars – glucose and galactose. After ingestion of foods containing lactose, in the absence of lactase, lactose enters the large intestine, where it is broken down by the microflora of the large intestine to produce gases (hydrogen, methane and carbon dioxide) and acids. Symptoms can vary from mild abdominal pain to cramps and diarrhoea.
People with low lactase activity tolerate lactose differently. For example, a glass of milk can cause symptoms in 50-60% of lactose intolerant people. However, if milk is drunk with food, the lactose is better tolerated because lactose absorption is slower. The same is true for fatty milk, as fat slows down the emptying of the stomach.
Lactase appears in the intestine of the foetus about 8 weeks before birth and is most active in infancy. When other foods enter the baby’s diet and there is no need for such a large amount of lactase, the activity of the enzyme decreases.
Around three quarters of the Earth’s population, especially the yellow and black races, have very low lactase activity, which is why they cannot tolerate milk. The peoples of northern Europe and their descendants in North America, who have long been pastoralists, have better preserved this activity. It is thought that about a quarter of the Estonian population is lactose intolerant, but many are not aware of this and do not have a problem because they do not drink as much milk.
2 forms of lactose intolerance
Lactose intolerance comes in two forms. Primary lactose intolerance is genetically inherited, age-dependent and usually occurs between 5 and 20 years of age. Typically, 50-70% of lactase activity is preserved. The disease is not curable. Secondary lactose intolerance is caused by temporary damage to the small intestine, which in turn may be the result of malnutrition, coeliac disease, inflammation of the small intestine, gastroenteritis or other diseases. Secondary lactase deficiency also occurs in babies and young children following bowel disease. Symptoms usually disappear within 2-4 weeks.
Diagnosing and managing lactose intolerance
Lactose intolerance can be guessed from the symptoms. Since lactose intolerance is a condition in which dairy products containing lactose should be avoided, and lactose plays a significant role in the human diet, there is good reason to be certain that it is the disease.
Indirect methods are widely used to diagnose lactose intolerance by feeding a person 50 g of lactose (equivalent to about a litre of milk) and measuring blood glucose levels after 10-15 minutes. If the blood glucose level does not rise, the patient is lactose intolerant. The other option is to analyse the breath. If there is an increase in hydrogen in the air, this indicates that lactose is being fermented by the microflora of the large intestine and that lactose intolerance is present.
Depending on the severity of the disease, the amount of lactose in the diet must be reduced to a greater or lesser extent. Usually, a person suffering from hypolactasia can tolerate 2-3 g of lactose per day. Preference should be given to sour milk products, in which part of the lactose has fermented into lactic acid, and to foods containing probiotic bacteria in particular, since some of the bacteria secrete lactase. In the case of lactose intolerance, a calcium deficiency may develop. Long-ripening cheeses with minimal lactose content are a good source of calcium. Capsules containing lactase are also available which can be consumed with foods containing milk sugar, i.e. lactose. Caution should be exercised when taking food supplements or medicines as lactose is often used as a filler.
Recommendations for a lactose intolerant person
A lactose intolerant person must not exclude dairy products from the menu under any circumstances! Calcium in milk is essential at all ages. It is very important to get enough calcium in the diet to prevent osteoporosis, otherwise bone regeneration is slowed down.
Lactic acid bacteria oxidise lactose to lactic acid and the resulting sour milk no longer contains lactose. This is why acidified dairy products such as sour milk, sour cream, kefir, yoghurt, curd and cheese are tolerated in hypolactasia. There is also a wide range of lactose-free products (milk, sour cream, yoghurt, cottage cheese, butter, cheese) available for consumption.
To prevent digestive upsets associated with lactose intolerance, follow these recommendations:
Acidified, fermented or lactose-free (LV) dairy products are recommended:
- buttermilk
- kefir
- yoghurt
- cheese
- milk LV
- Cottage cheese LV
- yoghurt LV
- or LV
- Cottage cheese LV
Foods that should be consumed in moderation:
- processed cheese
- cheese
- sour cream
- curd
- got from
- or
- mayonnaise
Foods that should be avoided or consumed in very low amounts:
- Milk
- cocoa with milk
- ice cream
- pett
- milkshake
- milk chocolate
- cakes made from pancake flour mixed with milk powder
If a person has an absolute intolerance to milk or sour milk products, nuts and seeds, beans, oranges, broccoli and soya products are good alternatives for calcium supplementation.
It is important to bear in mind that calcium cannot be absorbed without the presence of fat-soluble vitamin D. Calcium can also be absorbed in the diet. The main sources of this vitamin are fish (salmon, mackerel, tuna) and eggs. So if you can get calcium from plant foods, you should eat something fatty containing vitamin D as a side dish. The best choice is fish, which at the same time supplies the body with omega-3 fatty acids.
Attention should also be paid to other foods that are not made from milk, and to medicines. In the food industry, lactose is added to sausages, for example, to improve consistency, flavour and aroma, while in the pharmaceutical industry it is used as a filler in certain medicines. For this reason, people with lactose intolerance should carefully examine the composition of each food and medicine.
Based on national dietary recommendations.
This information has been confirmed by
Chairman of theBoard of Directors of theEastTallinn Central Hospital
6 July 2009 and supplemented by Riin Jõgi (former ETS Board member).