What is lactose intolerance and what are its symptoms. Also discover why it is produced, which foods are richer in lactose and which ones you can eat.

Within food intolerances or food intolerances itself, one of the most common is lactose intolerance, which stands out alongside gluten intolerance. In fact, it is believed that approximately 70% of the world’s population has some type of lactose intolerance or problem in their diet; and of that percentage, many of them are unaware of it.

It is how we see a more common type of intolerance than is thought, which occurs as a consequence of the existence in our body of a deficiency of lactase, an enzyme produced naturally by our small intestine, which is capable of breaking down lactose into glucose and galactose, so that they can be better absorbed by the body. However, if lactase levels are low, what is known as lactose intolerance appears.

What is lactose? 

The lactose (milk sugar), decomposes itself in two (glucose and galactose) simpler sugars, issue occurs thanks to the action of the enzyme lactase. This process takes place specifically in the small intestine, an organ where glucose can be absorbed into the bloodstream.

It is estimated that around 5% of milk is lactose, a disaccharide made up of a glucose particle and a galactose particle. It therefore becomes the main carbohydrate in milk.

What about lactose intolerance?

Within the process of absorption of lactose in the small intestine, when there is a deficit of lactase, lactose passes to the large intestine without decomposing and begins to ferment.  That is, the organism of the affected person has a low amount of lactase, which as we indicated earlier is the enzyme that makes milk sugar digestible.

This gives rise to gas and heartburn, which obviously generate a series of stomach problems and discomfort that you feel every time you eat a food that contains lactose.

That is, we can define lactose intolerance as the inability to digest normal amounts of milk sugar without discomfort or problems.

It is estimated that around 15% of the population does not have enough lactase in their body, so that when they consume a food with lactose they have great difficulties to digest it normally.

Symptoms produced by lactose intolerance

To some extent it can be difficult to know whether or not we are lactose intolerant, since although adverse reactions may exist or occur, many people are unaware that they have this condition.

And this is because the symptoms of lactose intolerance are not the same in all people, since it produces constipation, stomach discomfort, diarrhea … and others rhinitis, heavy digestion, or skin problems.

However, a more or less clear warning sign appears when drinking a glass of milk shortly afterwards a series of digestive symptoms appear, such as flatulence, colic and bloating. In fact, ingestion of a large amount of lactose is required for the most obvious symptom to appear: diarrhea.

Tests to diagnose this intolerance

Although the symptoms can help, it is best to have lactose tolerance tests, especially if you suspect that you may be suffering from this intolerance.

These tests measure the ability of the intestines to break down both lactose and other dairy products. There are basically two:

  • Blood test for lactose intolerance: It pursues the objective of looking for the presence of glucose in the blood, since when glucose is broken down our body produces it. It is considered normal if within 2 hours of ingesting a lactose solution the glucose rises more than 30 mg / dL, and abnormal if the glucose level rises less than 20 mg / dL.
  • Hydrogen breath test: it is the method of choice for most specialists. It consists of measuring the amount of hydrogen in the air that the person exhales. Its implementation is simple, since the patient is asked to breathe into a balloon-type container, and then drink a liquid flavored with lactose. These samples are taken in certain periods, verifying the level of hydrogen. Normally, when there is no lactose intolerance, there is very little hydrogen in the breath. However, it increases when the body has trouble breaking down and absorbing it. It is considered normal when the increase in hydrogen is less than 12 parts per million.

The diet in a person with lactose intolerance

Lactose-rich foods

Obviously, when a person suffers from lactose intolerance, they should reduce their consumption of milk and other dairy products. But from a nutritional point of view, it is far from advisable to completely eliminate the consumption of both milk and dairy products, since they are the foods that contain a higher concentration of calcium, essential to maintain a correct state of health of the bones.

Therefore, the key is to consume tolerated dairy, since the consumption of this type of food will produce an adaptation of our body, increasing tolerance to them over time.

However, below we summarize which are the dairy products with the highest presence of lactose: cow’s milk, powdered milk, milk shakes, dairy derivatives, cream, fresh and fermented cheeses, mascarpone cheese, Quark cheese, feta cheese, cream of milk, dairy desserts, butter, margarine, ice cream and bechamel sauce.

Dairy Lactose content (gr. Per 100 grams)
Cow milk 5
Goat milk 4.5
Sheep’s milk 5.1
Skimmed milk powder 5.3
Condensed milk 12.3
Fresh cheeses 2.4-2.7
Cured cheeses <1
Yogurt 2.7
Butter 0-0.5

Foods that may have lactose and you probably don’t know it

In addition to dairy products themselves, did you know that there are also some foods and food products that, in their composition, may contain lactose? The most common are the following:

  • Purees and soups: most contain lactose. They stand out the mashed potatoes and other creams or purees.
  • Bread: they usually carry milk or lactic ferments. It is important to look at the labeling or ask at the bakery where you usually buy bread.
  • Cold cuts and sausages.
  • Cakes and meat fritters.
  • Desserts: sorbets, cakes, yogurts, shakes, punches, milkshakes, milk chocolate.
  • Battered.
  • Fortified cereals.
  • Spirits.

We must also pay attention to other products that are not food but may contain lactose, such as:

  • Medicines
  • Vitamin complexes
  • Toothpastes

Lactose-free safe foods

Here are the foods you can safely eat if you are lactose intolerant. However, you can find out more information in our special article on lactose-free foods:

  • Natural fruit
  • Nuts
  • Cereals (not fortified)
  • Eggs
  • Honey
  • Jams and preserves
  • Potatoes
  • Rice
  • Pasta
  • meats
  • Vegetables
  • Fish
  • Vegetables
  • Tofu
  • Plant milks: soy, coconut, rice, almond, birdseed, walnut or oat milk.

As we can see, the key is to look at the nutritional labeling of the different foods and food products that you buy in the supermarket, and always inform yourself well about which ones you should avoid.

And what about lactose-free milk? Can they be taken safely?

Contrary to what is popularly and wrongly thought, lactose-free milk is neither more nor less healthy than normal milk. It’s just an equally natural drink that contains lower levels of lactose.

The only difference is that, when producing it, the producers add small amounts of lactase to the milk, so that what is achieved is that the lactose breaks down into glucose and galactose, the two molecules that, as we saw previously, form it.

Therefore, both lactose-free milk and low-lactose dairy are suitable for people with lactose intolerance, but it is not advisable to consume them if we are not intolerant, since small temporary lactose intolerances can occur.

On the other hand, foods low in lactose, such as lactose-free milk, are not suitable for those allergic to milk, since these types of foods continue to maintain the original proteins of animal milk.


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