Lactose intolerance




Food intolerances constitute a large group of disorders defined as adverse reactions to food and, unlike allergies, they do not involve the immune system.

While food allergies can manifest themselves, sometimes even in a violent way, immediately after eating the offending food, the disorders (symptoms) due to food intolerance can appear even after hours, in rare cases even after a few days making more difficult to relate them to responsible food.

There are different types of food intolerances. Some are determined by the body's inability to digest certain substances (enzyme intolerances). They are numerous and include a number of disorders related to the metabolism of carbohydrates, proteins and lipids due to the insufficient quantity of certain enzymes, ie proteins that they facilitate and increase the speed of chemical reactions (catalysts) Food intolerance on an enzymatic basis is generally already present at birth (congenital) but, sometimes, can be acquired over time.

The most frequent enzyme intolerance is that of lactose, the sugar present in the milk of all animal species (cow, sheep, goat, donkey, in addition to breast milk), and is due to the lack of the enzyme lactase which breaks down lactose into glucose and galactose. In the absence of the lactase enzyme, the body is unable to digest lactose and, consequently, in intolerant people it reaches the colon in quantities greater than the absorption capacity of the intestinal wall; the lactose that remains in the intestine ferments with the consequent production of gas and the onset of diarrhea.

Forms of lactose intolerance

Forms of lactose intolerance

There are three main types of lactose intolerance known:

  • lack, from birth, of the lactase enzyme which usually appears when the baby drinks milk for the first time. The infant must therefore be fed lactose-free infant formula. In fact, it is a very rare occurrence, not to be confused with the allergy to cow's milk proteins, more frequent during the first months of a child's life
  • lactose intolerance in preschool-school age, due to a progressive reduction in the activity of the lactase enzyme. This decrease is a normal (physiological) process that occurs after weaning. In some people, however, it leads to the disappearance of the enzyme in adulthood. It is the most common form of lactose intolerance
  • transient lactose intolerance, can occur due to acute diarrhea caused by an infection. This type of intolerance usually subsides in 3-4 months
Foods containing lactose

Foods containing lactose

Lactose is present in many foods. It is not contained, in fact, only in milk and its derivatives but also in many other products in which milk is present as an ingredient and lactose as an additive to soften or add taste, or as a preservative. For intolerant people this can be a real problem.

In our daily diet we find lactose in:

  • bread and other baked goods, snacks, biscuits
  • creams, margarine, salad dressings
  • precooked soups
  • meat preparations and sausages
  • drinks for breakfast
  • corn flakes, candies and other snacks
  • lactose powder found in some drugs
  • whey powder as a protein source in sports supplements

Although lactose is often present in these products only in minimal quantities, attention must be paid to the sum of the hidden (occult) quantities. It is therefore important to always check product labels before buying them. With the entry into force of regulation (EU) 1169/2011 on food labeling, in fact, it is mandatory to inform the consumer about the presence of so-called allergens in packaged products, highlighting it with a different character, such as size, style or color, compared to the others ingredients to allow quick viewing.



The symptoms (symptoms) caused by lactose intolerance are: gas in the stomach or intestines (flatulence), abdominal swelling, tummy rumbling (borborygmi), abdominal pain, diarrhea. Their severity depends on both the amount of lactose ingested and the extent of the enzymatic defect: some people cannot tolerate even the amount used to stain the coffee, others could safely drink a full glass of milk without having problems.

In fact, lactose intolerance often does not require the permanent elimination of the foods that contain it from the diet, but rather their reduction based on individual tolerance. The disorders (symptoms) caused by lactose intolerance can be common to many other diseases. To find out the cause, before removing milk and dairy products from the diet, it is important to visit the family doctor. symptoms that have appeared are, or not, related to lactose intake, the doctor may suggest eliminating all products that contain it from the diet for a couple of weeks and, subsequently, after assessing whether the disorders have improved, may prescribe the specific test to ascertain lactose intolerance.



The presence of milk and dairy products in the diet helps to meet the daily requirement of some nutrients necessary in all ages (read the Buffalo) such as, for example, calcium, zinc, phosphorus, selenium, vitamin A and B12 but, also, proteins of high biological value. People who do not consume milk and dairy products, because they are lactose intolerant, may experience deficiencies in the nutrients these foods are rich in. It is therefore recommended to introduce in the diet foods that can compensate for these deficiencies.

Some cheeses (for example, taleggio, gorgonzola, fontina, provolone, pecorino, parmigiano reggiano, grana padano, swiss cheese) can generally be consumed in moderation because they are rich in lactic bacteria or because they are subjected to prolonged aging. The enzymes and bacteria present, in fact, break down lactose into glucose and galactose making it digestible, as well as an excellent source of calcium.

Even yogurt, containing bacteria that partially digest lactose, is a food that can be consumed in moderate quantities even by people with intolerance.

Products for lactose intolerant subjects:

On the market you can find milk, and the products that contain it, with lactose already broken down into glucose and galactose (delactose). The milk thus treated acquires a sweeter taste, since galactose and glucose have a much higher sweetening power than lactose. In some of these types of milk calcium is added (added) to avoid dangerous deficiencies of this element in people who cannot eat the various foods based on cow (cow) milk, which is the most commonly consumed.

Good alternatives to cow's milk consist of different types of plant milk which also have the advantage of not containing cholesterol. However, they cannot be considered 100% substitutes because they are calcium deficient.

They include:

  • soya milk
  • rice milk
  • spelled milk
  • almond milk

If, for various reasons, even lactose-free foods cannot be taken, calcium supplements may be considered, if prescribed by the doctor.

In some cases, under medical supervision and prescription, it is possible to take tablets based on lactase, the enzyme that helps the body digest lactose; the tablets are taken immediately before eating the food that contains it.

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