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Lactase Deficiency (Disaccharidase Deficiency)

Generalized disease of the intestinal mucosa causes commonly a non-selective disaccharidase deficiency as these enzymes are present normally in the intestinal mucosa. In simple terms, Lactose Intolerance (Lactase Deficiency) is the inability to digest and absorb lactose.

Common Names

  • Disaccharidase Deficiency
  • Lactase Deficiency
  • Lactose Intolerance
  • Milk intolerance
  • Dairy products intolerance

What is Lactose and Lactase?

Lactose is the predominant sugar found in dairy products such as milk, cheese etc. Lactose is a larger sugar that is formed by two smaller sugars, glucose and galactose. Lactase is an enzyme found in the intestine that breaks down lactose into glucose and galactose which is then absorbed by the intestines and used by the body. When there is lactase deficiency, the lactose stays in the intestine, and is excreted in bowel movements.  This leads to Diarrhea, flatulence, abdominal bloating, and other abdominal discomforts.

Lactase breaksdown Lactose into glucose and galactose.

Lactase Deficiency

During recent years, several investigators have reported the occurrence of lactose intolerance in children due to lactase deficiency.

Three main types of lactase deficiency have been recognized:

(1)    Congenital lactase deficiency occurring in new born infants

(2)    Lactase deficiency associated with premature infants and

(3)    Acquired lactase deficiency occurring in adults and children

1. Congenital Lactase Deficiency

The infant cannot tolerate lactose due to the absence of the enzyme lactase in the intestinal mucosa. In the absence of lactase, lactose is not hydrolyzed to glucose and galactose. The accumulation of free lactose in the intestines causes fermentation, abdominal pain and loose motions.

Treatment: The treatment consists in giving a diet free from lactose. Milk substitutes, e.g., soybean milk containing glucose should be given.

2. Lactase Deficiency in Premature Infants

This condition occurs in premature infants due to decreased activity of the enzyme lactase in the intestinal mucosa. Initially these infants do not tolerate milk as they cannot utilize lactose effectively. However, the lactase content of the mucosa steadily increases in a month and the infants are able to tolerate and digest milk in adequate amounts.

3. Acquired Lactase Deficiency

This occurs in adults and older children and adolescents in many Asian and African countries. These subjects do not habitually consume milk and hence the activity of the enzyme lactase in the intestinal mucosa is low. When large amounts of milk are consumed they do not tolerate milk as lactose cannot be hydrolyzed and absorbed in the intestines. It is likely that the production of lactase, like many other induced enzymes, in the intestinal mucosa is stimulated by the presence of lactose. When lactose is not consumed, the synthesis of the enzyme is reduced.

Sucrase and Isomaltase Deficiency: Congenital sucrase-isomaltase deficiency has been reported to occur in some subjects. Acquired sucrase-isomaltase deficiency rarely occurs. In congenital sucrase-isomaltase deficiency, these enzymes are not present in the intestinal mucosa and the subjects do not tolerate sucrose or isomaltose.


  • Abdominal cramps
  • Abdominal bloating
  • Frequent Diarrhea
  • Floating stools
  • Foul-smelling stools
  • Gas (flatulence)
  • Malnutrition
  • Unusual Weight loss
  • Nausea
  • Slow growth

Lactase is formed in small intestine and the color intensity shows the amount of lactase enzyme.


1. Elimination of most of the dairy products (milk, yogurt, cheese, ice cream) from diet mostly improves the symptoms.  Studies have shown even with severe lactase deficiency some patients are able tolerate milk product. Most patients with low lactase levels can tolerate upto a half cup of milk. Anything more than this may cause problems.

2. Calcium supplements and Calcium rich foods should be taken to compensate the loss of calcium given by milk. Milk supplies Calcium, riboflavin, vitamin D and proteins so see to that you are able to get it from other foods.

3. Lactase supplementations have been proved to be effective for a majority of patients suffering from this condition.  Lactase is available in the form of Lactaid pills which are taken before consuming dairy.  Lactaid added milk is also available nowadays in many grocery stores.  Many people like this option because they feel frustrated if they have to completely eliminate dairy products.

Nutrition Details

Rich Calcium Sources: Leafy greens, Spinach, sardines, canned salmon, Baked Beans , oysters, Green peas, shrimp, orange juice and broccoli.

Milk Products that are little easier to digest: Buttermilk, Soy milk (for infants under 2 years), Hard Cheese, Goat’s Milk, Lactose free milk.

When to call the Doctor?

  • If the lactose intolerance symptoms are clearly seen
  • If the symptoms continue or gets worse


At present there no prevention methods. Just have a healthy diet routine and be fit. Try to do Yoga regularly, it’s the greatest naturally remedy.

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