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Lactose Intolerance

Last updated May 21, 2016

Lactose Intolerance is a condition that occurs when the body cannot digest or absorb lactose (a type of sugar) that is commonly found in milk and other dairy products, because it lacks the enzyme lactase.


What are the other Names for this Condition? (Also known as/Synonyms)

  • Dairy Product Intolerance (Lactose Intolerance)
  • Disaccharidase Deficiency (Lactose Intolerance)
  • Lactase Deficiency Disorder

What is Lactose Intolerance? (Definition/Background Information)

  • Lactose Intolerance is a condition that occurs when the body cannot digest or absorb lactose (a type of sugar) that is commonly found in milk and other dairy products, because it lacks the enzyme lactase
  • Consumption of products containing lactose would result in the signs and symptoms of Lactose Intolerance, which includes bloating and abdominal cramps. Severe and untreated Lactose Intolerance may lead to complications such as osteopenia and osteoporosis
  • The condition is caused when the body cannot produce an enzyme to breakdown the milk sugars. A few risk factors for Lactose Intolerance include advancing age, certain racial groups, certain health conditions, and cancer treatment
  • There is no cure for Lactose Intolerance, but its symptoms can be adequately controlled. Individuals who avoid dairy products from their diets have a favorable outcome

Who gets Lactose Intolerance? (Age and Sex Distribution)

  • Lactose Intolerance is generally observed in adults of all ages
  • No gender disparity is observed and both males and females are affected
  • Individuals of different racial and ethnic backgrounds are affected and no specific preference is generally seen
  • Some studies indicate the following about Lactose Intolerance:
    • Caucasians may develop Lactose Intolerance after the age of 5 years
    • African Americans may develop the condition as early as 2 years
    • Adults of Asian and Native American descent are more likely to be affected than Caucasians

Research has not established the reason behind such a behavior.

What are the Risk Factors for Lactose Intolerance? (Predisposing Factors)

The risk factors for Lactose Intolerance include:

  • Advancing age: The older one gets, the more likelier the condition may occur
  • Asians and American Indians have a higher risk for the condition
  • Premature birth: Premature babies do not develop the enzymes in sufficient quantities (within the cells) in the small intestine that produce lactase
  • Certain health conditions affecting the small intestine
  • Cancer therapy: Individuals undergoing radiation therapy to the abdomen have an increased risk

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Lactose Intolerance? (Etiology)

Lactose Intolerance is caused by the inability of the small intestine to produce enough quantities of the enzyme lactase that digests sugars (lactose) in milk and other milk products.

What are the Signs and Symptoms of Lactose Intolerance?

The signs and symptoms of Lactose Intolerance may include:

  • Bloating
  • Abdominal cramps
  • Gas
  • Diarrhea
  • Vomiting
  • Nausea

How is Lactose Intolerance Diagnosed?

Lactose Intolerance is diagnosed through the following methods:

  • A thorough physical examination and evaluation of medical history
  • Lactose tolerance test: The individual is given a liquid with high levels of lactose and blood glucose level is measured 2 hours later. If glucose levels do not increase, then it may indicate that the body is unable to properly absorb or digest lactose
  • Hydrogen breath test: The test measures greater than normal amounts of hydrogen in one’s breath, which occurs when lactose is not properly digested
  • Stool acidity test: A measurement of the acidity of stool can be used to detect Lactose Intolerance

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Lactose Intolerance?

The complications of Lactose Intolerance may include the following:

  • Osteopenia, which is low bone mineral density
  • Osteoporosis, in which the bones become thin and weak increasing the risk for fractures
  • Malnutrition

How is Lactose Intolerance Treated?

Presently, there is no cure for Lactose Intolerance. However, the symptoms may be controlled by the following measures:

  • Changing diets to control symptoms that includes eliminating or reducing the consumption of dairy products
  • Avoiding or discontinuing medications that contain lactose
  • Taking lactase substitutes, since lactase is the enzyme that breaks down lactose

How can Lactose Intolerance be Prevented?

Currently, there are no definitive methods to prevent Lactose Intolerance. However, avoiding lactose and lactose products can decrease the severity of the signs and symptoms.

What is the Prognosis of Lactose Intolerance? (Outcomes/Resolutions)

Lactose Intolerance has a generally good prognosis once the dairy products causing the condition are removed from the diet.

Additional and Relevant Useful Information Lactose Intolerance:

Custard made with milk, yoghurt, ice creams, and cheeses are some of the products that contain lactose.

What are some Useful Resources for Additional Information?

National Institute of Diabetes and Digestive and Kidney Disorders (NIDDK)
Office of Communications and Public Liaison
Building 31, Room 9A04 Center Drive, MSC 2560
Phone: (301) 496-3583
Fax: (410) 689-3998
Email: NDDIC@info.niddk.nih.gov
Website: http://www.niddk.nih.gov

References and Information Sources used for the Article:

https://www.nlm.nih.gov/medlineplus/ency/article/000276.htm (accessed on 3/28/16)

http://www.nhs.uk/Conditions/lactose-intolerance/Pages/Treatment.aspx (accessed on 3/28/16)

http://www.niddk.nih.gov/health-information/health-topics/digestive-diseases/lactose-intolerance/Pages/facts.aspx#who (accessed on 3/28/16)

http://www.mayoclinic.org/diseases-conditions/lactose-intolerance/basics/lifestyle-home-remedies/con-20027906 (accessed on 3/28/16)

Helpful Peer-Reviewed Medical Articles:

Pazgal, I., Brown, M., Perets, T. T., Niv, Y., Rachmilewitz, E., & Stark, P. (2014). Lactose intolerance is not the cause of gastrointestinal adverse effects in beta thalassemia patients treated with deferasirox. American journal of hematology, 89(9), 938-939.

Cellini, M., Santaguida, M. G., Gatto, I., Virili, C., Del Duca, S. C., Brusca, N., ... Centanni, M. (2014). Systematic appraisal of lactose intolerance as cause of increased need for oral thyroxine. The Journal of clinical endocrinology and metabolism, 99(8), E1454-E1458.

Mummah, S., Oelrich, B., Hope, J., Vu, Q., & Gardner, C. D. (2014). Effect of raw milk on lactose intolerance: a randomized controlled pilot study. Annals of family medicine, 12(2), 134-141.

Savaiano, D. A., Ritter, A. J., Klaenhammer, T. R., James, G. M., Longcore, A. T., Chandler, J. R., ... Foyt, H. L. (2013). Improving lactose digestion and symptoms of lactose intolerance with a novel galacto-oligosaccharide (RP-G28): a randomized, double-blind clinical trial. Nutrition journal, 12, 160-160.

Setty Shah, N., Maranda, L., Candela, N., Fong, J., Dahod, I., Rogol, A. D., & Nwosu, B. U. (2013). Lactose intolerance: lack of evidence for short stature or vitamin D deficiency in prepubertal children. PLoS One, 8(10), e78653-e78653.

Yang, J., Deng, Y., Chu, H., Cong, Y., Zhao, J., Pohl, D., ... Fox, M. (2013). Prevalence and presentation of lactose intolerance and effects on dairy product intake in healthy subjects and patients with irritable bowel syndrome. Clinical gastroenterology and hepatology, 11(3), 262-268.e1

Ojetti, V., Gigante, G., Gabrielli, M., Ainora, M. E., Mannocci, A., Lauritano, E. C., ... Gasbarrini, A. (2010). The effect of oral supplementation with Lactobacillus reuteri or tilactase in lactose intolerant patients: randomized trial. European review for medical and pharmacological sciences, 14(3), 163-170.

He, T., Priebe, M. G., Harmsen, H. J., Stellaard, F., Sun, X., Welling, G. W., & Vonk, R. J. (2006). Colonic fermentation may play a role in lactose intolerance in humans. The Journal of Nutrition, 136(1), 58-63.

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: May 21, 2016
Last updated: May 21, 2016

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