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Lactose intolerance: test your own predisposition

Do you sometimes suffer from symptoms such as tiredness, stomach pain or a bloated feeling after eating or drinking dairy products? And do you want to find out whether you may have lactose intolerance?

An iGene DNA test will allow you to learn a lot about yourself, including your predisposition to lactose intolerance.

In this blog article you can find out more about lactose intolerance, the traditional lactose intolerance test, DNA tests that can be ordered online and other personal traits that you can check or discover by taking a DNA test.

What is lactose intolerance?

Lactose is a sugar found in milk. Although most of us are perfectly capable of digesting lactose when we are babies, only 25% of people around the globe can digest it properly as adults. The other 75% of people experience symptoms of lactose intolerance (tiredness, a bloated feeling, etc.) after eating or drinking dairy products.

There are considerable differences between one part of the world and another. In Western Europe, for example, just 5 to 15% of people suffer from lactose intolerance, but the figure is a good deal higher in Asia, South America and Africa.

 lactose intolerance test

Primary and secondary lactose intolerance

We distinguish between primary and secondary causes of lactose intolerance. In the case of primary lactose intolerance your genetic predisposition plays a significant role; a certain mutation means that the enzyme lactase, which breaks down lactose, is not or is no longer produced. You can find out whether you suffer from this form of lactose intolerance by testing your predisposition to this condition.

With secondary lactose intolerance the intestinal wall produces insufficient lactase for other reasons. This may be a result of Crohn’s disease, for example.

The development of the lactose intolerance test

In the past the most accurate way of testing for lactose intolerance involved taking a biopsy to examine the tissue of the small intestine. This test looked at how much lactose was being converted to glucose by the enzyme lactase (the more glucose that was being produced, the better lactose was being broken down).

As this method was rather invasive, at a certain point this lactose intolerance test was replaced by an endoscopy, which involves taking images of the tissue using a flexible camera.

What other lactose intolerance tests are there?

In addition to the above methods, there are also various other ways of testing people for lactose intolerance, including the elimination/provocation diet, the hydrogen breath test and the DNA test.

Elimination/provocation diet

In the case of a so-called elimination/provocation diet you start eating a lactose-free diet and add increasing amounts of dairy (and other products containing lactose) over the period of the diet.

If you have no symptoms when not eating dairy, but experience symptoms when you incorporate dairy and other lactose-containing products into your diet, there is a fairly good chance that you are lactose intolerant. However, you should check whether other components of your diet could be triggering the symptoms of lactose intolerance.

Hydrogen breath test

A test that is commonly used to test people for lactose intolerance is the hydrogen breath test. This test involves measuring your breath after you have consumed 50 grams of lactose (the quantity contained in approximately five glasses of milk).

The hydrogen breath test is based on the fermentation of undigested lactose by your gut flora. This means that in some cases this lactose intolerance test can deliver inaccurate results, for example if someone is taking antibiotics or has abnormal bacterial activity for another reason.

DNA test

A simple and convenient alternative to the hydrogen breath test is a DNA test. Unlike most other tests, this test does not involve triggering symptoms of lactose intolerance. For adults of European origin in particular, a DNA test is an excellent alternative to a primary lactose intolerance test during the first stage of screening. An additional lactose intolerance test is needed in the case of children and for patients suspected of having secondary lactose intolerance.

Can you take a lactose intolerance test online?

For a short time now we have been offering the possibility of taking a lactose intolerance test on the basis of your DNA. Each variant of the iGene DNA test provides information on your predisposition to lactose intolerance. You can order all our tests online here.

iGene provides you with information not only on your predisposition to lactose intolerance, but also on countless other personal traits: from how likely it is that you will have red hair through to possible gluten intolerance, and from your blood group through to your predisposition to alcohol hypersensitivity.

Interested to find out if a DNA test is right for you? These seven questions will help you decide!


Mattar, R., de Campos Mazo, D. F., & Carrilho, F. J. (2012). Lactose intolerance: diagnosis, genetic, and clinical factors. Clinical and experimental gastroenterology, 5, 113-121.

Ridefelt, P., & Håkansson, L. D. (2005). Lactose intolerance: lactose tolerance test versus genotyping. Scandinavian journal of gastroenterology, 40(7), 822-826.

Swagerty, D. L., Walling, A. D., & Klein, R. M. (2002). Lactose intolerance. American family physician, 65(9), 1845-1860.

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