Lactose is a sugar present in milk and milk products. The lactase enzyme is required to digest lactose into glucose and galactose, the simplest forms of carbohydrates. When there is a lack of this enzyme present in the intestine, lactose passes through the intestinal colon unprocessed. This deficiency is called lactose intolerance. This condition can be the result of genetic inheritance, surgery, or an illness that alters the intestinal cells that produce the lactase enzyme. Typically, lactose intolerant sufferers should avoid dairy completely; however, a study conducted by the U.S. Department of Health and Human Services suggests that lactose intolerant individuals are able to tolerate 12 to 15g of lactose per day.

Symptoms of lactose intolerance include the following:

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

The severity of these symptoms may depend on the amount of lactose consumed.

There are certain diagnostic methods for detecting lactose intolerance:

• Lactose tolerance test: Two hours after ingesting milk, blood glucose (one of the carbohydrates broken down from lactose) is tested. If the blood sugar does not rise as it normally does, it is indicative of improper lactose digestion.
  
• Hydrogen breath test: Milk or milk products that are not digestible begin to ferment in the colon and produce hydrogen with many other gases that are absorbed by the intestines and exhaled with breath. This can cause the breath to smell like hydrogen a few hours after diary is ingested and would indicate a positive result.
  
• Stool acidity test: This test determines the acid content in stools due to the colonic fermentation. It is usually a test done in small children who are unable to complete the other diagnostic tests.
  

Congenital intolerance may be treated by gradually increasing the dairy product intake. This technique requires medical and nutritional supervision and may not work for all. For those individuals who are unable to raise their tolerance to dairy products, there are several other options:

• Avoid lactose completely by consuming lactose free or reduced lactose food.
  
• Ingest miniscule dairy portions or have them with major meals to slow down digestion and ease lactose digestion.
  
• Consuming lactase enzyme tablets or drops as recommended by a doctor.
  
• Reading food labels carefully is extremely important before the purchase of food, for they may contain dairy products.
  

A 2001 study by Anna and co-authors projected the small help that probiotic consumption can do in promoting lactose digestion. In fact, probiotics are more beneficial for the treatment of bowel symptoms associated with lactose intolerance.

Thus, individuals intolerant or less tolerant to lactose could follow some simple steps to make sure that they get proper nutrition and lead a healthy lifestyle.

References:

Lactose Intolerance. Retrieved from http://www.hopkinsmedicine.org/healthlibrary/conditions/digestive_disorders/lactose_intolerance_85,P00388/

Lactose Intolerance. Retrieved from http://my.clevelandclinic.org/health/diseases_conditions/hic_Lactose_Intolerance

What is Lactose Intolerance? Retrieved from http://www.lactoseintolerant.org/understanding-lactose-intolerance/what-is-lactose-intolerance/

(2015 Apr 14). Lactose Intolerance. Retrieved from http://www.mayoclinic.org/diseases-conditions/lactose-intolerance/basics/alternative-medicine/con-20027906

(2010 Feb). Lactose Intolerance and Health. Retrieved from http://www.ahrq.gov/research/findings/evidence-based-reports/lactint-evidence-report.pdf

Lactose Intolerance and Dairy. Retrieved from http://www.nationaldairycouncil.org/educationmaterials/healthprofessionalseducationkits/pages/lactoseintoleranceanddairy.aspx

De Vrese, M., Stegelmann, A., Richter, B., Fenselau, S., Laue, C. & Schrezenmeir, J. (2001). Probiotics-compensation for lactase insufficiency. American Journal of Clinical Nutrition, 73(2): 421s-429s. Retrieved from http://ajcn.nutrition.org/content/73/2/421s.full