L’intolérance au lactose


Lactose intolerance is a malabsorption of lactose caused by a deficiency in lactase, the enzyme responsible for its digestion. Lactose is a disaccharide made up of two monosaccharides, glucose and galactose. During digestion, lactose is divided into its two components under the action of the enzyme lactase. With lactase deficiency, lactose cannot be digested or absorbed and remains whole in the intestine. This causes a lot of water to enter the intestine, followed by bacterial fermentation of lactose and production of hydrogen gas, carbon dioxide and methane resulting in gas and abdominal pain.bdominales.


There are three types of lactase deficiency:

  • Congenital lactase deficiency eg. : rare lactase deficiencies.).
  • Primary or acquired lactase deficiency. This is the most common form of lactase deficiency. It is due to the decrease in lactase levels with age.e.
  • Secondary lactase deficiency. This is a lactase deficiency which can be caused by a disease that affects the ex intestinal lining. : celiac disease, by intestinal infection eg. : gastroenteritis or by surgery on the intestines.stins.


Symptoms of lactose intolerance may include abdominal pain and cramping, abdominal bloating or distension, gas or gas, diarrhea, nausea, and rumbling rumblings due to the movement of gas in the intestine.in).

Intolerance versus allergy

It is important to differentiate lactose intolerance from milk allergy. Lactose intolerance is a poor digestion of lactose due to lactase deficiency and accompanied by symptoms eg. : diarrhea, gas, abdominal pain. Milk allergy is a reaction of the immune system to proteins in milk. People who are allergic to milk can digest lactose normally, it is the milk proteins that trigger the allergic reaction.gique.

Individual tolerance

The degree of lactose intolerance can vary between individuals. Indeed, depending on individual tolerance, the speed of gastric emptying, the time of intestinal transit and the absorption capacity of the colon may be different from one person to another. Finally, factors such as age decrease in the enzyme lactase with age, the ex. : over 90 of Asians are lactose intolerant and the ex food form. : milk versus yogurt, naturally less rich in lactose can also have an influence on the degree of lactose intolerance.rance au lactose.

Nutritional treatment

Lactose intolerance can be controlled with a lactose free diet. However, as mentioned above, the degree of lactose malabsorption can vary from individual to individual. In addition, many people with lactase deficiency can tolerate up to 250-375 mL of milk before experiencing symptoms. As a result, nutritional recommendations should be personalized according to the needs and tolerance of each individual. In general, strategies that can be implemented to prevent the symptoms of lactose intolerance include:uent:

  • Ingest small amounts of lactose at a time.
  • Consume milk or dairy products with other foods during meals and / or snacks..
  • Choose dairy products containing less lactose, such as yogurts and hard or aged cheeses.
  • Opt for milk and dairy products without lactose or with a reduced lactose content.
  • Take lactase enzyme tablets as needed..

It is also important to ensure that individuals with lactose intolerance meet their calcium and vitamin D needs. This can be done through diet and / or supplementation. Finally, the strategies listed above are general recommendations, it is always best to consult a dietitian to obtain personalized nutritional recommendations based on your specific needs.s.



Bouthillier, Lise. January 2019. Diseases of the digestive tract. NUT 2047 Clinical nutrition 2. Montreal: University of Montreal.al.





Article written by:

Marie-Noël Marsan, Nutritionist