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Understanding Lactose Intolerance

Article written by Christine Arulappen.

Lactose intolerance is a common problem.  Genetic factors are a major cause, with an increased prevalence in Africa, South America and Asia where over 50% of the population are affected by this condition, and reaching almost 100% in some Asian countries.  This is compared to Australia and New Zealand, where only 6-8% of the population are affected.3

What is lactose intolerance?

Lactose intolerance occurs when the body produces insufficient amounts of lactase enzyme to breakdown lactose (milk sugar). Consequently, lactose remains largely undigested and results in unpleasant symptoms. Symptoms vary but may include1:

  • Abdominal pain and swelling
  • Flatulence
  • Diarrhoea
  • Nausea 
  • Vomiting

Foods containing lactose include milk and dairy products although the amount of lactose contained depends on the product.

Causes of Lactose Intolerance

There are three main types of lactose intolerance:

  • Congenital - is when someone is born with lactose intolerance and is related to genetic factors. 
  • Primary - is when someone develops lactose intolerance after childhood. 
  • Secondary - occurs after developing conditions such as Crohn’s disease, gastroenteritis or as a result of having chemotherapy2 

Diagnosing Lactose Intolerance

There are a number of ways to diagnose lactose intolerance, including: 

Hydrogen Breath Test
Hydrogen is produced when lactose reaches the colon because it has not been digested beforehand.2 This test measures the hydrogen levels in a person’s breath after they consume lactose.  If hydrogen levels are above normal the person has tested positive for lactose intolerance. This test can be obtained by getting a referral from your doctor. 

Elimination Diet
This involves removing all foods that contain lactose, gauging if your symptoms have improved and then re-introducing these foods back into your diet to see if symptoms return.2

If you don't have lactose intolerance yourself, it is likley that you know someone who does. A future article will look at how to manage this condition.

 

 

References

  1. Lomer, M.C.E. et al, 2008.  Review Article: Lactose Intolerance in Clinical Practice – Myths and Realities.  Alimentary Pharmacology and Therapeutics [Online] 27(2) p.93-103. Available at http://www.medscape.com/viewarticle/568556 [Accessed 9th June 2010].
  2. Praveen, Roy K., 2008.  Lactose Intolerance [Online]. Available at http://emedicine.medscape.com/article/187249-overview [Accessed 9th June 2010].
  3. Tuula, Vesa H. et al, 2000. Lactose Intolerance. Journal of the American College of Nutrition [Online] 19(2) p.165S-175S. Available at http://www.jacn.org/cgi/content/full/19/suppl_2/165S [Accessed 8th June 2010].


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Last updated 3/21/2011 1:37:09 PM