After the many articles written on the LactoSolution blog and many questions received from lactose intolerant people like us, we have understood that it is necessary to write a short guide - but as complete as possible - on the topic "lactose intolerance". Here you will find all the answers you are looking for and, if you have any further questions to ask, you can do so in the comments of the Lactosolution blog.

We will cover the following points:

  1. Lactose intolerance: what it is.
  2. Intolerance happens, let's frame lactose
  3. Symptoms and disorders that characterize lactose intolerance
  4. Tests to diagnose lactose intolerance
  5. Foods that contain lactose, what to eat and what not to eat when lactose intolerant
  6. The solution to the problems of lactose intolerance
  7. Who to rely on to understand the state of lactose intolerance and investigate any other pathologies?
  8. Medicines containing lactose
  9. Online stores that deal with lactose-free products
  10. Lactose intolerance in infants and children
  11. Legislative situation and associations in support of lactose intolerant
  12. Some theories on lactose intolerance

1) Lactose intolerance: what it is.

Lactose intolerance is a dysfunction of the organism that involves the mal-digestion of lactose , the sugar present in milk and its derivatives. It is given by the lack of the enzyme lactase , the catalyst responsible for processing lactose, or to divide it into glucose and galactose to complete the digestion of the same in the intestine. It is not an allergy, so it is not correct to say “lactose allergy”. An allergy can occur to milk proteins but it is a different thing (and, alas, with no solution).

Unfortunately, almost all people will experience intolerance in their lifetime because it has been so for hundreds of thousands of years. In fact, until a few thousand years ago (about 7,000 people think) we as a human race did not have genes capable of keeping the lactase enzyme functioning after breastfeeding. That is, we were designed to take milk only in the very first phase of our life.

Due to the increasingly massive use of milk and milk derivatives even in adulthood, the human body is adapting and therefore evolutionism is pushing us to maintain the lactase enzyme even after childhood.

Today about 25% of people in the world have these modified genes, adapted to "modern" times, being able to digest milk and dairy products well. The remaining 75% is predisposed to lactose intolerance and therefore will become intolerant over the course of life. The lack of genes used to create the lactase enzyme is called primary lactose intolerance .

Regardless of the genes, intolerance is transient in some cases. It may be due to antibiotic therapies that have decimated the presence of the lactase enzyme or non-chronic diseases and inflammations. In this case the body could go back to producing the enzyme and this is called secondary lactose intolerance.

2) Intolerance happens, let's frame the lactose

Lactose is a disaccharide, a molecule made up of carbon and water which is also called a carbohydrate or sugar. It is part of the carbohydrates oligosaccharides and is composed of two monosaccharides: glucose and galactose.

Other simpler carbohydrates are monosaccharides (glucose and galactose precisely) and others more complex are polysaccharides, composed of more than ten monosaccharides each (such as starch, glycogen and cellulose).

The only natural source of lactose is human or animal milk which represents 98% of the sugars present in milk as well as about 5% of the total milk mass.

Lactose is used in the pharmaceutical industry as an excipient and in the food industry for the production of infant formula. Lactose is also used as a thickener, softener and sweetener in some specific recipes.

3) Symptoms and disorders that characterize lactose intolerance

Symptoms of intolerance in adults or children are the same. Some are very common and some can be found in less than 20% of the intolerant population. Some might mistakenly call them "lactose allergy symptoms".

The most common lactose intolerance symptoms:

  • Poor digestion and constipation
  • Increased peristalsis
  • Flatulence and bloating 15 minutes to 3 hours after a meal
  • Diarrhea or poorly formed stools 1 to 3 hours after a meal
  • Abdominal cramps, abdominal pain, colic up to 24 hours after a meal
  • Sense of heaviness and abdominal swelling up to 36 hours after a meal

Less common symptoms of lactose intolerance:

  • Dizziness and headache
  • Nausea and vomit
  • Skin or throat irritation
  • Itching
  • Tachycardia
  • Insomnia
  • Constipation
  • Irritability
  • Fever
  • Rhinitis
  • Tiredness
  • Decreased hearing ability
  • Allergies
  • Muscle and joint pain
  • Prolonged pain in the abdomen

Where do these symptoms come from? Those responsible are the good bacteria of the intestinal flora of the colon. Due to the absence of the correct enzyme, lactose passes through the small intestine without alteration (natural home of lactase) and enters the large intestine. It is therefore up to these good microorganisms to get rid of them and, in the lactose fermentation process, they produce waste such as gas, hydrogen and methane, and some toxins. These latter substances give rise to swelling and pains and smells known to you.

The symptoms that afflict carriers of lactose intolerance are not specific, however, i.e. you can also have them in the face of other diseases such as: presence of helicobacterium (Helicobacter Pylori), Crohn's disease, irritable bowel syndrome (ISB). .. here we explain which in detail (LINK) .

4) Tests to diagnose lactose intolerance

Among the tests for lactose intolerance, the most famous and most used is the Breath Test , also called the breath test: a quantity of lactose powder dissolved in a glass of water is administered to the subject and the value of hydrogen in the breath at regular intervals over the next 4 hours.

An increasing value of more than 20 parts per million of H2 denotes a malabsorption of lactose and therefore a condition of intolerance (which can be reversible. The test does not indicate whether we will be forever intolerant or is a temporary condition).

It is performed in the hospital or in some analysis laboratories. Here the LINK with the detailed description.

Today there is a new type of Breath Test that more and more hospitals are offering and which, given the apparent higher quality and simplicity of execution, we also wanted to propose in our online shop ( This new methodology uses Carbon 13 instead of Hydrogen and is called C13 Breath Test or Carbon Breath Test.

In the case of the Carbon Breath Test the amount of lactose to be ingested is half compared to the Hydrogen Breath Test and the duration is also halved. We propose a test to be carried out at home, completely the same as that offered by the best hospitals ... better to go to the bathroom at home than in the ward!

The second test to diagnose lactose intolerance, complementary to the Breath Test, is the genetic test : with a sample of saliva (buccal swab) we go to study the genetic structure of the subject .

Also called DNA test for lactose intolerance, during the swab analysis, a particular genotype of our DNA is checked which indicates whether the body will undergo a decrease in the production of lactase enzyme (non-reversible condition). This too can be done in the hospital, in analysis centers and also, in some cases, by sending a sample remotely. Also for this test we have a specific article (LINK).

Only the combination of the two tests allows the diagnosis of the subject's current condition of intolerance at 100%.

A third test method for diagnosing lactose maldigestion is the lactose tolerance blood test . It is a rarely prescribed test that is performed on a blood sample by measuring glucose (blood sugar). It detects the conversion of ingested lactose into glucose and galactose.

5) Foods that contain lactose, what to eat and what not to eat

Where is lactose found?

There is a lot of confusion about the presence of lactose in foods. Let's try to clarify.

Some foods naturally contain lactose. Among them we find: milk and all its derivatives such as cheeses, buffalo mozzarella and not, slices, cream, creams, stracchino, robiola, yogurt. Dishes prepared with milk derivatives such as the beloved breakfast cappuccino, cannelloni, lasagna, ravioli and bechamel for lunch and

Other foods contain lactose because it is normally foreseen in their production or in their recipe and you must be wary of them regardless .

To understand if they are lactose free you have to look on the label ... the words "lactose" must not be present among the ingredients.

The wording "May contain traces of milk" should not worry you, because this wording informs that milk and dairy products are also processed in the vicinity of the food production line and some contamination may be possible (negligible contamination for us intolerant, more important for those with allergies in which even a few allergen molecules can trigger important reactions).

This "food category" includes desserts in general , from biscuits to cakes (tiramisu, panna cotta, cream), milk chocolate, packaged snacks, croissants, corn flakes, coffee in capsules, cappuccino and also salty foods such as cakes and preparations for ovens, pizzas, focaccia, milk sandwiches, snacks and energy bars.

Attention to homemade dishes such as cannelloni, lasagna and risotto, perhaps topped with bechamel. Vitamin supplements and lactic ferments may also contain lactose.

Finally, fast food foods (hamburgers, hot-dogs, sandwiches with cutlet or stuffed) are the masters, together with sauces (Greek, yogurt, barbecue), ready-made dishes (soups, risottos, ready-made sauces) and candies.

The same rule applies to ice cream ... usually all cream flavors contain lactose but not fruit ones. If in doubt ... ask the shopkeeper.

Sausages: hard salami and soft salamis, cooked ham and other soft and unseasoned specialties often contain lactose.

Lastly, foods that should not contain lactose.

Although some manufacturers may include lactose in the production processes of these foods for particular purposes, you can usually rest assured in purchasing them. In fact , there should be no trace of lactose in :

  • Alcohol (including spirits, wines and beers)
  • Meats (chicken, beef, pork and game)
  • Pure or dark chocolate, ground coffee
  • Fruits (apricots, black cherries, pineapple, avocado, bananas, cherries, watermelon, dates, kiwi, raspberries, almonds, apples, melons, blueberries, blackberries, hazelnuts, walnuts, peaches, pistachios, grapefruit, plums, grapes, etc.)
  • Plain bread and plain flours
  • Fresh fish (salmon, sardines, tuna, swordfish, trout, shellfish, octopus, etc.)
  • Farm products such as honey, eggs, caviar, etc.
  • Rice
  • Spices and condiments (including oil, vinegar, basil, rosemary, pepper, asparagus, cinnamon, cloves, curry, oregano, paprika, mint, chilli, poppy seeds, mustard, mayonnaise, ketchup, salt, sugar
  • Vegetables and vegetables (including lettuce, salad, broccoli, potatoes, artichokes, tomatoes, courgettes, beets, radishes, beans and green beans, turnips, broccoli, artichokes, carrots, cauliflower, cabbage, cucumbers, corn, onions, garlic, lentils, peppers , peas, radicchio, radishes, rye, popcorn, spinach)
  • Fruit juices and other preparations of the above foods without additions.

And what about the first "category" foods that advertise themselves as "lactose-free"?

Lactose-free milk, lactose-free mozzarella, lactose-free cream ... what are they?

Some producers have understood the importance of the lactose free sector and have begun to treat their foods with industrial lactase enzyme in order to ensure greater digestibility of the product even in the absence of overt symptoms of intolerability on the part of the consumer. The lactase enzyme causes the hydrolysis of lactose by converting it into glucose and galactose. These products are called delactosed , hence the more user friendly terms:

"Lactose free", "lactose <0.1%", "lactose <0.01%"

Attention, these products have a non-negligible percentage of lactose for most intolerant subjects. In fact, casuistry tells us that whoever takes delactosed products on a daily basis soon returns to have the same symptoms of intolerance in a very short time. In fact, there is lactose! Little, but there is and the organism "struggles" to digest it by encountering inflammation of the intestinal tract.

How can I replace foods containing naturally lactose instead of taking the same but delactosed?

There are many alternatives. For example, instead of cow's milk you can take almond milk, rice milk, soy milk, quinoa milk or milk from other cereals . Instead of butter you can use margarine.

And instead of cheese? The cheese itself! Provided it is aged for at least 24 months . In fact, during maturing the lactose is naturally broken down and in the long term the quantity reported is so low that it does not commonly cause problems, whether it is pecorino cheese, Grana Padano or Parmigiano Reggiano.

For yogurt , on the other hand, there is no alternative without natural lactose, you have to resort to delactosed yogurt (Zymil, I love to be ..). If you want to discover the properties of yogurt click here (LINK) .

Whey protein deserves a separate mention. This statement can be found on many food product labels and does not imply the presence of lactose in the product . Any presence of lactose must be indicated separately in the product packaging.

But beware of protein food supplements (milk proteins, those for the gym to be clear) as it is very difficult to find them without lactose in their composition. Look for whey protein isolate and read nutritional labels carefully if you want to supplement your diet with high protein.

6) The solution to the problems of lactose intolerance

Most people - and even many doctors - think there is no solution to lactose intolerance . Fortunately, however, this is not the case.

It is indeed true that the condition of lactose intolerance is not regressable (except for temporary or secondary intolerance due to specific disorders) it is equally true that in order not to suffer from its effects there is a very simple solution .

Instead of buying the aforementioned lactose-free products advertised, it is enough to take the lactase enzyme orally to digest the lactose contained in all common foods!

The degradation of lactose that occurs within our body by taking one or more tablets of a good lactase enzyme supplement is very similar to the splitting of lactose that would occur in the case of the body's production of the same lactase enzyme. So you no longer have to worry about running to the bathroom after eating your favorite mozzarella pizza or your friend's birthday ice cream cake if you use a good lactase supplement.

The effectiveness is high, so much so that for 95% of the people we interviewed this method works great (with the Lactosolution 15000 product) . The classic pains and annoyances disappear and you can only have some secondary annoyance which, however, does not affect living well.

However, this effectiveness is only valid if the enzyme taken is of a certain type, that is lactase enzyme (not beta-galactosidase) and if the dosage is high enough . Since the correct dosage varies from person to person and also from one day to another based on what we eat (you can learn more by reading HERE an interesting article - LINK ), it is necessary to move towards products with a high concentration of the active ingredient lactase such as Lactosolution 15000 .

The lactase supplement is not a drug but, in fact, a nutritional supplement . This means that it has neither contraindications nor side effects.

To ensure good efficacy, follow the advice for taking the lactase enzyme in our article (LINK, click HERE) .

In support of the enzyme supplement, you can take lactic ferments to help keep the intestinal flora functional . Enterogermina, Enterolactis Plus, Probinul and Proflora Guna are good alternatives without lactose in their composition. However, we always recommend that you seek medical advice before making any decisions for your health.

7) Who to rely on to understand the state of intolerance and investigate any other pathologies?

The most suitable professional to investigate the appearance of symptoms is the gastroenterologist . He will be able to tell you which tests to do, above all he will understand if there are the requirements to undergo a colonoscopy. He will be able to indicate any medications and supplements and will give you, given in hand, your health condition.

Once you understand that you are intolerant, you can rely on a good nutritionist for the diet to follow. The nutritionist biologist doctor has the skills to ensure a quiet life for your intestines, understands the impact of lactose on an intolerant body and will be able to help you make your life choices.

The pharmacist , on the other hand, will be fundamental for the choice of lactose-free drugs and lactose-free foods available on the market.

8) Medicines containing lactose

Many, too many drugs contain lactose. To date, for example, there is no birth control pill that does not contain lactose.

Some lactose-free antibiotics that, following a medical prescription, you could take without problems related to lactose intolerance are the following:

  • Ambramycin
  • Augmentin
  • Bramicil
  • Cedax
  • Ciproxin
  • Gentomil
  • Levoxacin
  • Unixime
  • Zithromax in oral suspension

If you can't find a lactose-free alternative to the prescribed medication that suits your needs, remember that there are lactase enzyme supplements that can solve the problem.

9) Online stores that deal with lactose-free products

Some stores are specializing and some have several lactose-free foods in their catalog.

I list two where I buy regularly, by clicking on the name you will access the website:


The garden of books

10) Lactose intolerance in infants and children

Can children be lactose intolerant?


And as with adults, intolerance can be congenital or acquired.

Care must be taken in order to correctly understand the condition of intolerance in children. The symptoms are in fact the same previously seen for adults (diarrhea in newborns, flatulence, swelling to which the crying of the newborn is added) and are comparable to the disorders that every newborn faces daily in the first months and years of life.

By clicking HERE you can find out more about lactose intolerance in children and babies - LINK.

11) Legislative situation and associations in support of lactose intolerant

Unlike celiac disease (aka gluten intolerance), lactose intolerance is not a condition supported by government funds . In practice, the intolerant person must take charge of purchasing specific products completely at his own expense, without any facilitation.

There is an association that fights for our rights, it is called Associazione Italiana Latto-Intoleranti (AILI) and offers a company card with which it offers discounts and information on the subject. The Association's policy does not seem to be to help manufacturers of lactase enzyme supplements but rather to push on lactose-free products, in fact they also sell a free certification ...

12) Some theories on lactose intolerance

We conclude the discussion of the subject by informing you of two "opinions", two "movements of thought" that often meet often when it comes to lactose intolerance.

A) "A period of a lactose-free diet - also called detoxification - makes intolerance go away"

Many believe that if a person with lactose intolerance stops taking lactose for 6 months or more, the symptoms tend to disappear. Someone even says that after this period the person could tolerate lactose again and therefore eat foods that contain it.

According to this theory, lactose accumulates as we eat foods that we could not, until it saturates the body and makes us feel bad. By stopping eating milk and dairy products, or by eliminating the consumption of lactose, the one already accumulated in our body should slowly disappear and we would have a higher tolerance threshold than when we started the diet.

Some call this period, erroneously, detoxification (erroneously because lactose is not a toxic substance for our body, although it can give us problems. Toxins are in fact represented by: Alcohols that is alcoholic molecules, aldehydes, methylglyoxal, acetones, short-chain fatty acids).

What does the scientific literature say about it?

Kindly comment on me by linking the source if you find any publications in favor of this theory because I have not found any data regarding a permanence of lactose for such a long period in our body.

In fact, lactose follows the normal digestion cycle and is excreted from the body via the faeces within 48 hours. Therefore, over a period of 2-3 days, the “accumulation” effect has its own logic and continuing to take lactose in the short term can only lead to an aggravation of symptoms.

Stopping lactose intake for a few days and taking it every other day is definitely good and right. Striving not to take it for 6 months doesn't seem to have a scientific reason. What is certain is that intolerance will not disappear even after 1 year of a strict diet. As we have seen, in fact, the most common lactose intolerance is due to the lack of the lactase enzyme due to genetics and genes do not go back in their steps so easily.

B) "Not eating lactose makes us intolerant"

I have personally interviewed several doctors on the subject. An interesting theory but also not confirmed by scientific publications believes that abstaining for a prolonged period from foods with a high lactose content can cause the decrease in production of the enzyme lactase in our body and therefore the onset of intolerance to lactose.

A striking example is the boy who substitutes tea for milk for breakfast throughout his secondary school period. There are some cases in which intolerance has arisen as a result of this behavior but the questions arise: "Would the boy have become intolerant anyway if he had continued to take milk?" or "perhaps he felt like switching to tea because he perceived some disturbance with milk (preliminary signs of an already developing lactose intolerance)?".

In the absence of sufficient scientific documentation this theory remains a hypothesis. For our part, we can be careful not to completely eliminate milk from our diet so as to hope that our body's production of the enzyme lactase never stops. However, a subject who is genetically predisposed will not benefit from this tactic, at least not in the long run.

It should be noted that the two theories presented are in stark contrast. According to the latest theory, in fact, an iron lactose-free diet as proposed in the first theory could completely eliminate the production of lactase within the body with even more serious intolerance effects than when the same diet was started.

Personally , after 10 years of intolerance and more than 500 interviews, I am more oriented towards the second theory. Even assuming the fact that more and more doctors indicate that it is incorrect to totally eliminate lactose from the diet of those who are lactose intolerant , trying instead to understand which threshold makes us feel bad and which one we tolerate. This is because milk and dairy products bring many nutrients to our body, some not otherwise assimilable.

A good lactase enzyme supplement will be your greatest ally in supporting a complete diet lifestyle, leaving you the freedom to choose what to eat from time to time.

I have reported many links for further information, the goal is to make it easy for you to understand what it means to be lactose intolerant nowadays.

You can also follow some Facebook groups on lactose intolerance where people advise each other (but be careful to filter the information ... in these contexts too often we talk without scientificity or any preparation).

I hope you enjoyed my article. On our site you can find the registration form for the Lactosolution newsletter, useful for receiving updates on the best BLOG relating to lactose intolerance!

Faced with all this, what is your idea or your question? Write it below!

Purchase link for Lactosolution 15000 lactase enzyme food supplement: click HERE (LINK)!

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  • Nielsen date
  • Lehninger Principles of Biochemistry, Fifth Edition; David L. Nelson and Michael M. Cox
  • European Journal of Biochemistry, various articles
  • American Journal of Clinical Nutrition, various articles
  • Paolo Silvestrini - Fundamentals of chemistry
  • Questionnaires submitted to intolerant people 2017, 2018, 2019 by Lactosolution
See the author's articles
Dr. Marco Verducci

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