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Symptoms of lactose intolerance include:

People with lactose intolerance may feel uncomfortable 30 minutes to 2 hours after consuming milk and milk products. Symptoms range from mild to severe, based on the amount of lactose consumed and the amount a person can tolerate.



Bloated stomach (abdomen)

Abdominal pain


Cold sweat

There are people , however, who can experience these symptoms for other reasons than food intolerance. For this reason it is absolutely essential to have a test done by a medical professional, if a person believes they may be suffering from food intolerance

How is lactose intolerance diagnosed?

Lactose intolerance can be hard to diagnose based on symptoms alone. People may think they suffer from lactose intolerance because they have digestive symptoms; however, other conditions such as irritable bowel syndrome can cause similar symptoms. After taking a medical history and performing a physical examination, the doctor may first recommend eliminating all milk and milk products from the person’s diet for a short time to see if the symptoms resolve:

'The home method'  

This involves avoiding eating foods that contain lactose for a couple of days and then drink two to three glasses of milk. If you get a stomach ache or diarrhoea within half an hour, you may be lactose intolerant.

Hydrogen Breath Test. 

The person drinks a lactose-loaded beverage and then the breath is analyzed at regular intervals to measure the amount of hydrogen. Normally, very little hydrogen is detectable in the breath, but undigested lactose produces high levels of hydrogen. Smoking and some foods and medications may affect the accuracy of the results. People should check with their doctor about foods and medications that may interfere with test results.

Stool Acidity Test. 

This is  is used for infants and young children to measure the amount of acid in the stool. Undigested lactose creates lactic acid and other fatty acids that can be detected in a stool sample. Glucose may also be present in the stool as a result of undigested lactose.

Lactose tolerance test.

This requires measuring blood sugar levels after drinking lactose. If sugar levels rise the patient is not lactose intolerant.

Directly measuring lactase activity

This requires obtaining a sample of small intestinal lining obtained during endoscopy. This test requires inserting a tube into the stomach

This information has been sourced, in part from the following sources: Net Doctor UK  Dietitians of Canada  Food Intolerence Network  Web MD National Digestive Diseases Information Clearinghouse