Symptoms Of Lactose Intolerance

Symptoms Of Lactose Intolerance

Lactose intolerance is the inability to properly digest lactose, sugar in milk, and an insufficient enzyme lactase presence. The disorder, which is estimated to affect at least 40% of Italians, may be of genetic origin, and therefore appear as early as childhood or manifest itself in adulthood. This article will give you a complete guide about symptoms of lactose intolerance, causes & treatment.

The problem originates in the small intestine. In fact, lactose is a disaccharide which, to be properly digested by the body, must first be broken down into the two simple sugars that compose it: galactose and glucose. This splitting takes place in the small intestine by the lactase enzyme, which like all enzymes, has the main task of facilitating the assimilation of specific foods, “reducing” them to simpler elements. If the lactase enzyme is deficient or absent, the lactose cannot be digested and remains to ferment in the intestinal lumen.

“There are various degrees of lactose intolerance, and they depend, in fact, on how consistent and reversible the lactase enzyme deficiency is,” explains Dr. Beatrice Salvioli, Humanitas Gastroenterologist. “This means that some intolerant individuals can take limited doses of lactose without side effects.”

What are the symptoms?

“When lactose, like any other undigested food residue, remains in the intestinal tract, it is fermented by the bacterial flora. The fermentation process draws liquids into the colon and increases gas production. In this way:

  • meteorism
  • flatulence
  • swelling
  • abdominal pain
  • diarrhea
  • constipation

Nausea, headache, exhaustion, and skin rashes may also occur. Symptoms appear after eating foods that contain lactose but can change a lot from person to person because they depend on the severity of intolerance and the type of meal ingested.

Why does one become lactose intolerant?

Intolerance can be genetic or acquired. In the first case, the body cannot produce enough lactase enzyme; the disorder usually occurs from the weaning period. In a rarer form, the newborn is completely lactase-free and exhibits symptoms already when fed breast milk. However, in all other cases, lactose intolerance is acquired or secondary and can arise at any age. It can be the consequence of pathologies, injuries, and inflammation of the intestine or antibiotic therapies that inhibit the lactase enzyme activity. In these cases, the problem is transitory: it is necessary to eliminate the lactose sources for 3-6 months and then gradually reintroduce them.

What tests do you need to undergo?

The most common diagnostic test to ascertain lactose intolerance is the breath test, a non-invasive test that consists of analyzing the air exhaled by the subject before and after administering a dose of lactose. In fact, when the milk sugar is not digested and begins to ferment, there is a hyper-production of hydrogen: if the test reveals that the exhaled air is excessively rich in this gas, it means that the intolerance. On the other hand, a genetic test can ascertain the possible origin or genetic predisposition (both homozygous and heterozygous) of the disorder.

What shouldn’t we eat?

By eliminating all lactose sources from the diet, you don’t necessarily have to give up all dairy products. “Aged cheeses (such as parmesan, parmesan, provolone, and pecorino) generally do not give problems, unless the intolerance is severe,” explains Dr. Salvioli. The cheese maturing process considerably reduces lactose, which is therefore non-existent or non-problematic in the final product. On the other hand, it is necessary to avoid cow’s milk, goats and other animals, fresh cheeses (mozzarella, Certosa, and soft cheese), and all milk-based products (ice cream, butter, creams, bread, baked goods, milk…). Alternatively, you can consume lactose (lactose-free) milk and dairy products enriched with Lactobacillus acidophilus (a bacterium that digests lactose) or based on lactase or predigested lactose.

What does it mean to be lactose intolerant?

Lactose intolerance occurs when the intestinal cells lose the ability to synthesize lactase. The enzyme can digest the sugar in milk and its derivatives and divide it into two simpler and easily digestible sugars for the body, such as glucose and galactose. If the lactase does not fully carry out its work of splitting lactose, the undigested part present in the intestine reaches the colon: here, thanks to the bacterial flora, a fermentation process takes place, which is the main cause of gastrointestinal disorders.

So what are the most frequent symptoms of lactose intolerance?

Symptoms vary from case to case, depending on the level of lactase enzyme deficiency, but generally, the clinical picture predicts the onset of one or more gastrointestinal symptoms:

  • Abdominal pain
  • Sense of swelling
  • Nausea
  • Constipation or diarrhea
  • Meteorism and flatulence

However, these symptoms can often be associated with other more general symptoms such as:

  • Headache or dizziness
  • Sense of tiredness
  • Itching and skin rashes
  • What are the causes of lactose intolerance?

Lactose malabsorption may depend on a deficiency in lactase production, and in this case, we speak of a genetic or primary form. If this form occurs from birth, we speak of congenital form, which remains a scarce case history.

How is lactose intolerance diagnosed?

To ascertain if you are actually lactose intolerant, it is advisable to undergo diagnostic investigations. The methodologies currently used are two:

The H2-Breath Test or Hydrogen Breath Test analyzes the breath before and after the administration of 20-25 g of lactose. The patient is blown into a bag at regular intervals (every 30 minutes) for a total time of 3-4 hours. The 6 air samples taken are then examined to identify hydrogen from the fermentation of the undigested lactose. A positive test result ascertains the presence of lactose malabsorption, which diagnoses intolerance to this sugar.

The genetic test, which studies the genetic composition highlighting the predisposition to lactase enzyme deficiency. This test consists of a painless sampling of the mouth’s mucous membrane using a swab. The positive result allows us to establish whether it is primary or secondary lactose intolerance.

How is lactose intolerance treated?

To date, there are no drugs or special treatments. The only recommended therapy is the exclusion of products containing this sugar, up to the remission of symptoms in the case of secondary intolerance or permanently in the primary form. In both cases, the need arises to know exactly which foods contain lactose, which is not only, as you might think, milk and its derivatives, but also canned or frozen foods, which use lactose as a preservative and thickener. or drugs that use this sugar as an excipient.

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Lactose and the problem of intolerance

Lactose intolerance is a condition in which the consumption of milk and dairy products causes a non-allergic reaction that manifests itself with gastrointestinal disorders such as bloating, crampy pain, and occasional diarrhea. Intolerance fault is attributable to the lack or reduction of enzymes responsible for the digestion of lactose, the sugar contained in milk and its derivatives. These enzymes, present in the ” brush border ” of intestinal cells and called lactase, are responsible for splitting lactose into the two sugars that make it up: galactose and glucose. The first is essential for forming nerve structures in the child; the second is the organism’s primary energy substrate. To be digested, lactose must necessarily be broken down into these two simpler units.

The problem of lactose intolerance is more prevalent among Asians and Orientals, while Europeans are generally more resistant than other populations.

In some rare cases, lactose intolerance may be due not to the lack of lactase as to the deficiency of the proteolytic enzymes necessary for the digestion of milk proteins.


Lactose intolerance can be primary or secondary and transient. In the first case, the organism does not produce lactase due to a genetic defect; for this reason, the symptoms of intolerance manifest themselves already in early childhood. When this deficit does not exist, the organism can still suffer from a transitory intolerance, called secondary, due to the enzyme’s temporary loss. Infections or lesions of the gastrointestinal tract and sudden dietary mutations are the most common causative factors behind this condition. In other words, food stimulation may represent an insufficient stimulus for the synthesis of lactase adequate to temporary needs.

Even undiagnosed celiac disease, due to the degenerative process that affects the intestinal surface responsible for absorbing nutrients, can be based on lactose intolerance.

Treatment and therapy: Symptoms Of Lactose Intolerance

For further information: Medicines for the treatment of Lactose Intolerance. In secondary lactose intolerance, the first approach is to consume milk and dairy products in small quantities and then gradually increase them to stimulate lactate production.

To allow milk to all those who suffer from intolerances towards it, lactose milk is available on the market in which lactose is found, for the most part (70-75%), already broken down into glucose and galactose. Alternatively, you can “settle” for soy milk or rice milk.  Finally, those suffering from lactose intolerances can benefit from the consumption of probiotic foods (“special” yogurt or particular freeze-dried lactic ferments ).

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Symptoms Food intolerances

Food intolerance is an adverse reaction of the body to certain foods. Unlike what happens in food allergies, this reaction does not depend on the immune system’s abnormal activation with its antibodies. Therefore, we can consider food intolerance as a malaise triggered by the ingestion of particular foods, even in common use, such as wheat, dairy products, and eggs.

There are different types of food intolerances. The most common enzymatic intolerance is that of lactose in the milk; Intolerances can also occur due to the presence in some foods of substances with pharmacological activity (or produced by the intestine starting from them), such as vasoactive amines (e.g., histamine and tyramine ), caffeine, and ethyl alcohol. Even food additives ( flavor enhancers, sweeteners, preservatives, etc.)

There is probably a predisposition to intolerances transmitted by inheritance; however, other factors can also contribute, such as diseases, stress, unbalanced diet, and alterations of the intestinal bacterial flora—Symptoms Of Lactose Intolerance.

Symptoms of food intolerances and allergies

Food intolerances can cause various recurrent and persistent disorders, especially at the gastrointestinal, dermatological, or respiratory level. Unlike allergies, symptoms do not appear violently immediately after food ingestion but can arise over time. Regarding the digestive system, abdominal bloating, flatulence, canker sores, loss of appetite or excessive appetite, nausea, constipation or diarrhea, and prolonged or difficult digestion may arise. Food intolerances can also cause water retention, sudden weight changes, hyperacidity, gastritis, irritable bowel syndrome, or colitis.

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Among the respiratory manifestations of food intolerances are colds and other recurrent infections of the airways. From a dermatological perspective, dermatitis, hives, acne, and other skin rashes can arise. Also, dizziness, headache, drowsiness, chronic fatigue, anxiety, insomnia, and mild forms of depression may occur.

In the case of food intolerances, it is necessary to eliminate for a few months, under medical supervision, the foods responsible for the disorder, replacing them with others capable of satisfying the organism’s nutritional needs. After the abstinence period, you can try to reintroduce these foods into the diet gradually.

Most common symptoms and signs

  • Acne
  • Anorexia
  • Asthenia
  • Increased appetite
  • Weight gain
  • Bubbles on the Tongue
  • Burning in the tongue
  • Heartburn
  • Dizziness
  • Bad digestion
  • Colic
  • Abdominal cramps
  • Stomach cramps
  • Depression
  • Diarrhea
  • Difficulty concentrating
  • Dyspnea
  • Dysentery
  • Abdominal distension
  • Pain in a Flank
  • Abdominal pain
  • Encopresis
  • Flatulence
  • Abdominal swelling
  • Abdominal gurgling
  • Fecal incontinence
  • Insomnia
  • Thinness
  • Stomach ache
  • Headache
  • Functional Meteorism
  • Nausea
  • Dry skin
  • itch
  • Cold
  • Acid regurgitation
  • Water retention
  • Drowsiness
  • Constipation
  • Swollen stomach

Medicines: Symptoms Of Lactose Intolerance

It is possible to control and avoid the symptoms deriving from lactose intolerance by paying attention to avoiding foods that contain it, especially milk and fresh cheeses; those intolerant to milk, on the other hand, seem to tolerate the administration of aged cheeses and yogurt positively. There is no drug capable of reversing the disorder; therefore, the patient must reduce the amount of lactose introduced with the diet, avoid calcium deficiency; to escape this inconvenience, it is advisable to enrich the diet with calcium supplements.

However, although lactose intolerance cannot be cured definitively with drugs, it is possible to take enzyme substitutes formulated with lactase; as we have analyzed, in fact, a person intolerant to milk has a deficiency of lactase enzymes, therefore a specific supplementation, even if it does not solve the problem completely, can attenuate the symptoms.

  • Lactase: given that the body of a patient suffering from lactose intolerance is deficient in lactase, an integration of these digestive enzymes could be of great help. It is recommended to take the product one hour before a meal. Consult your doctor.
  • Calcium: Calcium supplementation is not useful for healing from lactose intolerance; rather, it is recommended because, by not consuming milk and dairy products, the body may be deficient in this important mineral.
  • Calcium Carbonate (e.g., Idracal, Carbosint, Lubical, Eurocal D3 ): contains 40% calcium (400 mg of calcium) contained in 1 gram of calcium carbonate). The supplement is available as effervescent tablets, chewable tablets, and sachets. Take the supplement during the meal or immediately after (indicative dose: 900-2.500 mg per day).
  • Calcium citrate: 210 mg of calcium are present in 1 gram of calcium citrate. Take the supplement with or immediately after a meal.


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