From an epidemiological point of view, there is great variability of lactase deficiency disease known as lactose intolerance, depending on geographic area. Populations who do not consume milk (Australian Aborigines, Eskimos, American Indians, the Chinese) have an incidence of lactose intolerance in the adult population at the rate of 40% – 90%. Populations which, throughout history, have grown animals (Europeans and their descendants) have an incidence of lactose intolerance in the adult population at a rate of 5% -15%.
Congenital lactose intolerance, occurs immediately after birth and is manifested by diarrhea. Primary lactase deficiency late-onset or late-onset lactose intolerance is a relatively normal situation. Thus, after weaning, in the infant has place a repression of the lactase activity. An adult has about 5% – 10% of the lactase activity of the newborn. The primary deficit is a hereditary condition regarded to ethnic group without implication of geographical location, environmental conditions and current milk consumption. It is believed that persistence of lactase activity is an adaptive genetic mutation (produced in populations that are growing animals and consuming milk), and lactase deficiency is a relatively normal condition.
Acquired lactase deficiency or lactose intolerance secondary to inflammatory bowel disease: celiac disease, Crohn’s disease, etc.
On microscopic examination the intestinal mucosa has a normal aspect, only the use of immunohistochemical techniques can highlight a decrease or absence of the enzymatic equipment. Only in secondary lactose intolerance will appear changes which are characteristic for the primary disease.
Clinical signs of disease are relatively typical and yet are ignored by the patient for years. Signs of disease may vary, depending on lactase deficiency and the amount of lactose that is consumed. Typically, after consuming milk or milk derivatives, in patient with lactose intolerance will occur in a few tens of minutes bloating, gurgling, explosive watery stools and flatulence.
From obvious clinical signs or clinical suspicion, may be done a food sample, asking the patient to ingest 250-300 ml of milk on an empty stomach, and to follow the effect for 2 or 3 hours. If there are clinical signs described, the diagnosis is certain.
Lactose tolerance test, which consists of three phases: clinical, biological and radiological. First is determined the patient fasting plasma glucose, then is given 50 g lactose in 400 ml water and a package of barium sulphate. Will be taken glucose level at 1 and 2 hours and will be performed a abdominal X-ray at one hour. Interpretation of results:
- Clinical: diarrhea, flatulence will indicate a positive clinical test;
- Biological: the absence of glucose increased more than 25% of the fasting value is a positive test;
- Radiological: in the lactose intolerance will appear a dilution of the barium, relaxed bowel loops and accelerated bowel movements.
Lactose intolerance generally has a favorable evolution, because patients restrict their diet, avoiding milk products In some cases, especially undiagnosed malabsorption can occur because of prolonged diarrhea.
In the case of lactose intolerance, the treatment is clearly dietetic, and consists of a reduction or complete removal of milk and dairy foods.A solution is represented by the appearance of lactase preparations of bacterial origin, such as Lact-Aid. Coadministration with a meal of 2 or 3 tablets will ensure the assimilation of the lactose and prevent symptomatology.