BlogWhat is really lactose intolerance?
June 11, 2021by BIOLAN HEALTH

Many people feel some discomfort, or even become ill, when they drink or eat dairy products, without being aware of it until they discover that, in fact, they are lactose intolerant. But, what is really lactose intolerance?

In this post, we will try to offer some information about the causes, symptoms, diagnosis and treatment of this pathology, as well as a series of dietary recommendations for the prevention and treatment of it.

Let us start by understanding the disease itself.

Among the components of dairy there is a sugar called lactose; it is a disaccharide made up of glucose and galactose. Lactose is the main sugar in milk and dairy products. Milk contains 5 g of lactose per 100 mL. This amount is practically the same in whole or skim milk, regardless of whether the milk is from cow, sheep or goat.


In our digestive system, the one in charge of breaking down lactose into simple sugars that can be efficiently absorbed by the intestine is an enzyme called lactase, produced by the small intestine. When the levels of this enzyme are very low, we are not able to digest lactose, since, by not being able to break it down, it reaches the large intestine, where it undergoes bacterial fermentation, generating a set of symptoms known as intolerance to lactose.

These symptoms, which can appear between 30 minutes and two hours after the intake of dairy products, although they are not life threatening, they can be quite uncomfortable for those who suffer them. The variety and intensity of symptoms depends on each person, and may include shortness of breath, nausea, vomiting, abdominal pain or bloating, flatulence, allergic rash, abdominal cramps, or diarrhoea.

If these symptoms have been experienced after the consumption of dairy products not only occasionally, but also repeatedly, a greater or lesser degree of lactose intolerance may be suspected. To confirm the diagnostic, it is necessary to go to your specialist, who will advise you on the diagnostic tests that can be performed to confirm the pathology.

Traditional diagnostic tests to confirm lactose absorption capacity are:

  • duodenal biopsy,
  • lactose tolerance test, or
  • hydrogen breath test.

The first one consist on a highly invasive procedure. The other two tests, despite not being particularly invasive, consist on the intake of a high amount of lactose. In the lactose tolerance test, an increased blood glucose is related with an appropriate digestion of lactose. In the case of the hydrogen test, an increase in the exhaled hydrogen amount is related with lactose malabsorption, which generates fermentation producing an increase in hydrogen levels.


In recent years, the urine gaxylose test has been incorporated into the market, a test that, unlike those mentioned, is non-invasive and does not generate, in lactose intolerant people, the discomfort of ingesting a high amount of lactose. This new method is based on the oral administration of a small amount (only 0.45 g) of gaxylose, a lactose analogous that can be broken down by intestinal lactase into glucose and xylose. The amount of xylose excreted in the urine is therefore correlated with intestinal lactase activity, which represents a direct measure for the diagnosis of lactose intolerance. Despite being a precise and non-invasive method, the measurement of xylose in urine requires expensive and voluminous equipment, which limits its use to the central laboratories of hospitals with the consequent delay of the results.

In this sense, BIOLAN HEALTH has developed, together with VENTER PHARMA, a Point of Care (PoC) solution for xylose measurement in urine: the OSAXYL system. A portable, precise and easy-to-use device that in just 30 seconds is capable of quantifying the xylose excreted in urine and indicate whether the patient is lactose intolerant. A very valuable tool that allows an immediate diagnosis to be obtained at the specialist office.

One frequent asked questions after a diagnostic confirmation is: why am I not generating enough lactase? Insufficient intestinal lactase production can appear in three different situations:

  • Congenital lactase deficiency, in which the absolute absence of lactase from the first days of life is due to a genetic issue.
  • Secondary lactase deficiency, which occurs when the ability to produce this enzyme is temporarily lost because of an intestinal disease.
  • Primary acquired lactase deficiency, in which lactase is correctly expressed from birth, but the production capacity of this enzyme is lost while aging.

It is estimated that at least 65% of the world population is lactose intolerant, with populations or regions in which the frequency of this disease is significantly higher than in others.

Although there is no cure for this disease by the moment, symptoms can be reduced by controlling the intake of products with high lactose content.

However, it must be kept in mind that milk and dairy products in general are a very complete and balanced food group, whose consumption is recommended at all ages of life since they provide proteins of high biological value, fat, vitamins, potassium and calcium. In fact, milk and its derivatives, such as cheese or yogurt, are the main group of foods to cover the needs of calcium and vitamin D in the diet, essential for a good bone health, so limitation or completely avoiding dairy products can lead to malnutrition, so it is best to adapt eating habits to your pathology.

Dairy products have different amounts of lactose, and lactose intolerants can still tolerate small amounts of lactose, so they can experiment with different dairy products to find adequate nutritional options that do not cause them stomach upset. For instance, low-fat hard cheeses have very little lactose. Another option is to opt for yogurts or other fermented dairy products such as kefir, which, in addition to having lower lactose content than milk, their living bacteria can aid in the lactose digestion. Another option is to replace normal dairy products with lactose-free dairy, in which lactose has previously been degraded to simple sugars to facilitate its digestion.

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