Lactose Intolerance

Description of Lactose Intolerance

Lactose intolerance is a widespread metabolic disorder caused by the inability to digest lactose due to a shortage of the lactase enzyme. Lactase activity is high during infancy, when milk is the main source of nutrition, and declines after the weaning phase in most mammals.

Approximately 75% of the world’s population loses the ability to digest lactose. The prevalence of adult type lactose intolerance varies depending on ethnicity, from less than 5% in north-western Europe to almost 100% in some Asian populations. Clinical symptoms of lactose intolerance usually begin 30 minutes to 2 hours after eating or drinking foods that contain lactose, such as dairy products.

The onset of symptoms is directly related to the quantity of ingested lactose. The severity of symptoms varies, depending on the amount of lactose each individual can tolerate.

It is important to distinguish lactose intolerance from other conditions, for example irritable bowel syndrome, which have very similar symptoms.

Common symptoms of lactose intolerance and conditions with similar symptoms

Typical symptoms after consuming food or drink containing lactose

Abdominal bloating

Abdominal pain



Failure to thrive

Nausea Steatorrhea (excess fat in stool)

Stomach cramps


Conditions with similar symptoms

Celiac disease

Cows’ milk protein allergy (casein and whey)

Crohn’s disease

Irritable bowel syndrome

Ulcerative colitis


Treatment for lactose intolerance includes a lactose-restricted diet.

The extent of dietary changes depends on how much lactose a person can consume without exhibiting symptoms.

Additionally, a lactose-intolerant individual may use commercially available lactase (LactAid, Lactase, DairyEase etc.), which reduces the lactose to glucose and galactose.


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What is important to consider about intolerance testing

It’s important to understand that not all intolerance tests that you find on the internet are scientifically validated or accurate. Additionally, the interpretation of test results can be complex, and false positives or false negatives can occur.

That said, there are a few aspects to consider when evaluating intolerance tests:

  1. Scientific Validity: Look for tests that have been scientifically validated and have undergone rigorous testing to ensure accuracy. Tests that use evidence-based methods and have been published in reputable scientific journals are generally more reliable.
  2. Laboratory Accreditation: Choose tests offered by laboratories that are accredited by relevant authorities or have certifications indicating adherence to quality standards. This can help ensure the reliability of the test results.
  3. Comprehensive Analysis: Some tests may offer a more comprehensive analysis by testing for a wide range of potential intolerance or sensitivities, including food, environmental factors, and other triggers. This can provide a more holistic view of potential triggers for symptoms. Unfortunately based on the currently available knowledge comprehensive tests are only available for allergy but not for intolerance.
  4. Professional Guidance: It’s advisable to seek professional guidance from a healthcare provider, such as an allergy consultant or a registered dietitian, before and after undergoing intolerance testing. They can help interpret the results, provide recommendations for further testing if needed, and assist in developing an appropriate management plan. Please be aware that if you are promised to receive  interpretation of the results without a detailed history taken by a healthcare professional, such interpretation might not be addressing the nature of your concerns and might not be relevant.
  5. Cost and Accessibility: Consider the cost and accessibility of the test, as well as any additional fees for interpretation or follow-up consultations. Keep in mind that some tests may be expensive and not covered by insurance. Please think twice before ordering cheap tests covering everything as they might not be worth it.

It’s important to remember that intolerance testing is just one tool in the diagnostic process and should be used in conjunction with a thorough medical history, physical examination, and possibly other diagnostic tests. Ultimately, the goal is to identify and manage any underlying causes of symptoms effectively, which may require a multidisciplinary approach involving healthcare professionals.

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