The lactose intolerance is the partial or complete inability of some individuals to digest lactose, a sugar found in milk and dairy products. This is because these people produce in sufficient quantity or produce lactase enzyme responsible for breaking down and decompose lactose in the human body. Thus, lactose reaches the large intestine unchanged and has to be fermented by bacteria that produce lactic acid and gases.

It is important to differentiate intolerance to lactose of milk allergy. The first is a digestive disorder that occurs due to deficiency of the small intestine to produce lactase. The latter, moreover, is averse immune reaction to milk proteins, which usually occurs after the individual ingest a certain amount of milk or dairy products.

The degree of intolerance varies widely, but the disorder is very common. In Brazil, 70% of people have it to some degree, whether mild, moderate or severe.

Types and classification:

There are three main types where lactose intolerance is divided. Are they:

Congenital deficiency: it is a genetic problem, so the child is born with a problem that prevents the production of lactase, this type is considered chronic and very rare to happen.

Primary deficiency: it turns a natural and progressive decrease in the production of the enzyme lactase, beginning in adolescence to the end of life, such type is the most common to happen.

Secondary Deficiency: In this type, the lactase production is affected by any intestinal disease such as diarrhea, irritable bowel syndrome, Crohn’s disease, celiac disease or allergy to milk protein. In these situations, the intolerance is temporary and disappears along with causing disease problem.


Symptoms only appear if someone who is lactose intolerant consume any product containing the substance. Generally, they happen from 30 minutes to 2 hours after ingestion. They pass naturally, but if the patient continues ingesting lactose, the symptoms tend to get worse.

The most common symptoms are: abdominal bloating, cramping, diarrhea, flatulence, nausea, anal burning, rashes and slower growth or weight loss for babies or children.


The lactose intolerance is not a disease, so there is no specific treatment for it. The patient can live normally adapting your diet and using certain medications.

Some dairy products are more digestible and can be eaten in moderation by who has the disorder. They are: butter and cheese milk; fermented dairy products such as yogurt; goat milk, which must be ingested together with meals and supplemented with essential amino acids and vitamins if offered to children; ice cream, milkshakes, and aged or hard cheeses; milk and dairy products without lactose; cow’s milk treated with lactase to older children and adults; soy formulas for children less than 2 years; soy milk or rice for small children.

Furthermore, there is the option of adding lactase enzyme to normal milk before ingesting it or take enzymes in capsules.

Milk is an important food in calcium, so it’s important that people who are intolerant to lactose find other ways to meet the need of the body’s calcium.