What are the most common food intolerances, what symptoms do they cause, how are they diagnosed and how are they treated : lactose intolerance, celiac disease and favism .
Food intolerant: lactose intolerance
Lactose intolerance is the most frequent food intolerance, with an incidence of 50% in Mediterranean populations reaching 80-95% in black people.
Lactose intolerance is generally caused by the progressive loss of lactase activity .
Lactose is the sugar contained in milk and its derivatives; it is a disaccharide composed of galactose and glucose which, to be absorbed, must be split into the intestine by an enzyme called lactase: this enzyme decreases with increasing age and in the adult the lactase activity is reduced to 5-10 % compared to birth.
Lactase deficiency leads to failure to break down lactose into glucose and galactose: undigested lactose is fermented by intestinal bacterial flora causing diarrhea and meteorism.
More rarely lactose intolerance can be congenital or secondary to intestinal damage due to infectious or inflammatory processes.
The diagnostic test that shows the deficiency of the enzyme and the consequent lactose intolerance is the breath test - breath test - which is used to measure the concentration of protons in the breath: the protons are the result of the fermentative activity of the intestinal flora.
To avoid the symptoms caused by lactose intolerance it is necessary to exclude foods that contain lactose, paying attention to hidden lactose sources: lactose can in fact also be present in cured meats, chocolate, bread and pre-cooked foods. It is therefore necessary to replace milk with vegetable alternatives such as soy milk, coconut, almond or rice and carefully read the labels of the foods you buy at the supermarket.
Read also Food intolerances what they are and how they are treated >>
Food intolerances: celiac disease
Celiac disease, or celiac disease, is another quite frequent intolerance also known as gluten intolerance. Gluten is the protein fraction of wheat, barley, rye, oats, spelled, kamut, triticale; it is composed of gliadin and glutein and gluten intolerance is a chronic intolerance to gliadin.
Celiac disease causes lesions of the intestinal mucosa and partial or total atrophy of the intestinal villi, causing diarrhea, malabsorption and anemia.
The procedure to diagnose gluten intolerance consists of an objective examination to assess absorption disorders, serological tests to measure the presence of gliadin antibodies in the blood and an intestinal biopsy to assess villus damage.
When celiac disease is diagnosed, the cure consists in avoiding all foods that contain gluten : in addition to the cereals already mentioned, it is necessary to pay attention to the gluten present in other foods, including beer, breaded products, melted cheeses, nuts, salsa di soy and sauces in general, cocoa paste.
It is therefore good to read food labels carefully, avoid sauces, condiments, beer and food additives - the EC has established that the presence of gluten must be reported on the food packaging - and also pay attention to the contamination of utensils and surfaces intended for food preparation, frying oil, cooking water and grill.
Naturally gluten-free foods include rice, corn, quinoa, buckwheat, amaranth, millet, potatoes, chestnuts and legumes; there are also gluten-free dietetic-therapeutic foods on the market and supplied free by the National Health System. The Italian Celiac Association has prepared a handbook with food and safe medicines.
Food intolerances: favism
Favism is a less known hereditary intolerance than the previous ones that is diagnosed through serological tests. Favism is caused by a genetic enzyme deficiency: the deficiency of the enzyme glucose-6-phosphate dehydrogenase (an enzyme involved in a metabolic cycle called the pentose phosphate cycle) is a hereditary deficiency, frequent in tropical and subtropical regions.
Individuals with this enzyme deficiency may experience serious problems after taking some drugs and ingesting beans, hence the name favism. In fact, the beans contain substances that in the presence of the enzyme deficiency destroy red blood cells causing anemia and consequent weakness, pallor, vomiting and haemolytic crises.
In the most serious cases there is hemolytic anemia, which can only be resolved by transfusions. In case of favism it is necessary to avoid the intake of beans, especially raw, and oxidizing drugs.
