Lactose intolerance in children

What is lactose intolerance?

The most common symptoms include bloating, gas, abdominal pain, and diarrhea.

Lactose intolerance is a disorder caused by the inability to digest the sugars in milk due to a deficiency of an enzyme called lactase.

Also known as lactase deficiency or hypolactasia.

Lactase facilitates the digestion of lactose, a sugar present in milk and its derivatives.

What are the causes of lactose intolerance?

Lactase is an enzyme produced by cells that line the small intestine, and takes care of break down lactose in glucose and galactose, two more easily digestible sugars that pass into the blood.

Most children produce lactase at birth, which allows them to digest lactose as babies. Lactose is the main sugar in breast milk.

Most mammals stop producing lactase when weaning occurs, however humans continue to produce lactase throughout life.

Sometimes not enough lactase is produced to break down all the lactose that is ingested, so the unabsorbed lactose passes through the intestine without being digested. The undigested lactose, is partially broken down by bacteria in the intestine. This fermentation process produces the bowel irritation and causes the accumulation of gas and diarrhea.

A child can become lactose intolerant due to:


Lactose intolerance can occur at any age and in children of any ethnic group, although it is very rare for it to appear from birth.

In many cases, lactase deficiency developsspontaneously over time. When children reach 3 to 6 years of age, lower amounts of lactase begin to be produced.

In some children, production continues to decline or even stops altogether. Symptoms of lactose intolerance often appear in adolescence or early adulthood.

Some ethnic groups (particularly black, Hispanic, Asian) are more likely to develop lactose intolerance.

Infections or allergic reaction

Damage to the small intestine occurs, leading to a temporary reduction in lactase levels.

Usually this damage is temporary, and after a few weeks or even months, the child can tolerate dairy products again.

Chronic diseases

Such as celiac disease, Crohn's disease, or parasite infection can also cause temporary lactose intolerance.

Lack of iron

Lack of iron in the diet can interfere with lactose digestion and absorption.

Symptoms of lactose intolerance

Many people with lactose intolerance have a different tolerance level, meaning they can consume a certain amount of lactose with minimal symptoms.

Symptoms of lactose intolerance include:

  • Abdominal pain
  • Abdominal swelling
  • Flatulence
  • Diarrhea

Diagnosis of lactose intolerance

It is a very common but very poorly diagnosed disease, both by excess and by default.

When a child has symptoms of lactose intolerance, one of the ways is removing dairy products from the diet for a few weeks. After this time, you can begin to reintroduce milk into the diet in small amounts.

If the child's symptoms improve during the dairy-free diet and return hours after he has returned to drinking milk, the diagnosis of lactose intolerance is considered.

Another way to diagnose lactose intolerance is by testing hydrogen test. When lactose is not properly digested in the gut, it is eventually fermented by bacteria in the gut, causing more hydrogen to be produced.

This test consists of checking the amount of hydrogen that is exhaled in the breath at regular intervals. A first collection is made on an empty stomach, then a lactose solution is ingested and the expired air is collected again every 30 minutes, for a total of 3 hours.

Although they are less frequent, other tests such as the stool acidity analysis or one biopsy.

Treatment of lactose intolerance

It depends on the intensity of the symptoms.

When symptoms are mild, they can improve just by reducing the amount of dairy in your diet.

But when the child is very sensitive to small amounts of lactose, it will be necessary to eat a lactose-free diet, including any derivative of milk. Therefore, it will be necessary to take extreme precautions by checking all foods and the labels of packaged products to ensure that they do not contain milk in their composition.

Milk is a good source of nutrients

If the child must eat a lactose-free diet, it is important to supplement it with calcium, vitamin D, and riboflavin.

Related Reading:

  • Food allergies
  • Foods to avoid allergies in children