Little Known Symptoms of Lactose Intolerance

Lactose intolerance isn't too serious but its symptoms can affect the life of those who have it.
Little Known Symptoms of Lactose Intolerance

Last update: 26 May, 2022

The symptoms of lactose intolerance aren’t life-threatening but the discomfort can certainly interfere with a person’s life. Are you ready to find out more about it? Go on reading then because you’re about to discover what the little-known signs for this condition are — it’s an increasingly common disorder.

Lactose intolerance is a disorder that manifests due to a deficiency in the enzyme (lactase) responsible for digesting lactose. This lactase deficiency, produced in the small intestine, leads to malabsorption and the milk sugar goes straight to the colon, where it ferments and generates gas.

To understand this a little better, experts indicate that “all infants have lactase in their intestines to digest breast milk and almost everyone produces less lactase as they get older. When the amount of lactase is no longer sufficient, people begin to show symptoms of lactose intolerance after consuming dairy products.”

Symptoms of lactose intolerance


A woman with a belly ache.

The U.S. National Library of Medicine informs that symptoms begin between 30 minutes and 2 hours after eating or drinking dairy products.

The severity of symptoms depends on the person and the amount of dairy consumed. How much (or little) lactase is present in the stomach also determines their intensity. In general, the symptoms are:

  • Gases
  • Diarrhea
  • Cramps
  • Nause or vomit
  • Bloating or stomach pain
  • Perianal reddening

In addition, kids and teens who are lactose intolerant often experience nausea and vomiting.

In addition to the above-mentioned signs of lactose intolerance, chronic cases (secondary lactase deficiency), may also manifest as:

  • Explosive stool movement
  • Abdominal spasms
  • Perianal redness
  • Noticeable weight loss

Additionally, patients with secondary lactase deficiency may present with skin problems, extreme tiredness, and pain in the extremities.

How to detect lactose intolerance


Do you think you may have this problem? Then, it’s important that you see a specialist. A professional can diagnose your symptoms. The most common tests are:

A glycemic response test for lactose intolerance

  • First, blood is drawn to measure initial glycemia levels
  • Then an overload of lactose is given: 50 grams every 30 minutes for 2 hours (4 doses)
  • After that, blood is drawn again to measure glucose

If the measurements are the same, there is something wrong with lactase. However, this test is not very specific. There are other disorders that can alter glycemia. An example is diabetes mellitus.

Hydrogen Breath Test


A man with foul breath.

This is the test doctors order the most often to diagnose lactose intolerance. The National Institute of Diabetes and Digestive and Kidney Diseases explains that people must drink milk, and then blow into an airtight bag every 15 minutes.

When the small bowel can’t digest milk sugar, it moves into the large bowel. The bacteria present there to use it as food and produce hydrogen. Therefore, if your breath has a good amount of hydrogen, maybe it’s due to a problem digesting lactose.

Small Bowel Biopsy

The samples necessary for this study are obtained by esophageal or gastrointestinal endoscopy. These fragments of intestinal tissue are subsequently analyzed in the laboratory for the presence or absence of lactase in the mucosa.

Stool Acidity Test

This test is mostly for small children. Because of their young age, other studies can be risky or impractical. It detects lactic and other fatty acids in the stool. Its presence is the result of lactose fermented by bacteria in the colon.

A genetic test for lactose intolerance

The goal of this test is to detect primary lactose intolerance due to a variant of a gene called MCM6A blood or saliva sample is all it takes to analyze the two polymorphisms related to this condition.

You still don’t know if you’re lactose intolerant?

Consult a doctor and have a check-up as soon as possible if after reviewing the list of signs of lactose intolerance you suspect that you may have this problem. It’s the best way to find out for sure and learn how to deal with it in order to avoid discomfort.

Be sure to tell your doctor about any doubts you might have so he can clear them. It’ll help you understand the best daily course of action to follow.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.