Lactose intolerance: what it is, symptoms, how to diagnose it

What is lactose

The lactose it is the sugar naturally present in milk. Unlike other sugars, it has a lower sweetening power than sucrose, about 40%. His too glycemic index is low: corresponds more or less to half that of white bread. Lactose is digested by a specific enzyme, lactase, naturally present in our intestine.

Lactose intolerance

Lactose intolerance – we read on the website of the Ministry of Health – it is a disorder that can appear in a person at any age and can manifest itself in a more or less important way depending on the subject and depending on the type and quantity of food ingested.

Intolerance is caused by absence or by low presence of lactasewhich is the enzyme that breaks down lactose into glucose and galactose.

We remember that intolerance is different from allergybecause while intolerance is a reaction that does not involve the immune system, allergy is a much more serious condition, which involves the immune system and can even reach to put in danger the life.


Disorders caused by lactose intolerance can include gas in the stomach or intestines (flatulence), abdominal bloatingrumbling belly, abdominal pain, diarrhea.

Their severity – the ISS experts underline – depends on both amount of lactose ingested than by 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.

However, before removing the milk and dairy products from the diet, it is important to visit the family doctor. The symptoms caused by lactose intolerance can in fact be common to many other diseases. To understand whether or not the symptoms that have appeared are linked to lactose intake, the doctor may suggest eliminating all products that contain it from the diet for a couple of weeks and, subsequently, after evaluating whether the disorders have improved, could prescribe the specific test to ascertain lactose intolerance.

Therefore, it is important to pay attention not to confuse generic symptoms (for example a little swelling after drinking milk) with an intolerance, which should always be diagnosed with specific clinical tests and evaluated by specialists.


The most common diagnostic test is the breath test, also called Breath Test. It is an exam non-invasive which consists in the analysis of the air exhaled by the subject examined, before and after having ingested a dose of lactose.

Genetic examination, on the other hand, can ascertain any predisposition to the disorder.

Where is lactose contained

The higher health institute on its site provides very useful information to recognize the foods that contain lactosea substance, as we will see below, present in many foods.

Lactose, in fact, is not only contained 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 preservative.

In our daily diet we find lactose in:

  • bread and other baked goods, snacks, biscuits
  • creams, margarine, salad dressings
  • pre-cooked 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 sum of hidden quantities (occult). 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 font, such as size, style or color, compared to the other ingredients to allow a quick visualization.

What to eat

Some cheesesfor example, taleggio, gorgonzola, fontina, provolone, pecorino, parmigiano reggiano, grana padano, swiss cheese – we read on the ISS website – can generally be eaten in moderation because rich in lactic bacteria or because they have been subjected to prolonged seasoning. 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.

Also it yogurtcontaining bacteria that partially digest lactose, it is a food that can be consumed in moderate quantities even by people with intolerance.

However, on the market there is milk, and the products that contain it, with lactose already broken down into glucose and galactose (delactosed). 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, the soccer to avoid dangerous deficiencies of this element in people who cannot eat the various foods based on cow’s milk (cow’s milk), which is the most commonly consumed.

Good alternatives to cow’s milk consist of several types of Vegetable “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, they can be taken into consideration calcium supplementsif prescribed by your doctor.

In some cases, under medical supervision and prescription, it is possible to take lactase-based tablets, the enzyme that helps the body digest lactose. The tablets should be taken just before eating the food that contains it.

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Lactose intolerance: what it is, symptoms, how to diagnose it

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