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Lactose sugar … Where is there and some facts about lactose sensitivity


What foods contain lactose? Those with lactose intolerance ask themselves this question every time they should go shopping. Lactose intolerance or milk sugar intolerance is a condition that many suffer from due to their inability to digest this sugar in their bodies.


Lactose sugar

What is lactose or milk sugar?

Lactose is a type of sugar found in the milk of all mammals, such as cows, goats, sheep and humans, and it is also found in many prepared foods. Milk sugar (C12, H22, O11) is called natural lactose, consisting of glucose and galactose .

What is lactase?

Lactase is the last enzyme that appears and matures in the body of a baby who is about to be born. Its maximum activity appears at the time of birth and during the nursing period and then begins to decrease after weaning. This enzyme is essential for digestion and the breakdown of lactose into two simple sugars, glucose and galactose.

Where is lactase found?

Lactase is found in the small intestine and its distribution is irregular. Its activity is highest in the first parts of the intestine and is not found in the stomach and colon.

What is meant by lactose intolerance or lactose intolerance?

Lactose intolerance is a disorder that arises after ingestion of lactose, due to a deficiency of the enzyme responsible for digesting this substance.

When sugar is poorly absorbed, the sugar passes into the colon where it is fermented and generates gases.

The consumption of milk or ice cream by a person with this condition does not cause serious or irreversible damage to the intestine, but its symptoms are fleeting.

Many people think that they have this problem when they are actually suffering from excessive bacterial growth, digestive disorders, or enteritis.

The genetic mutations allowed humans to continue consuming dairy products into adulthood. However, there are those who do not produce enough enzymes to absorb lactose and this happens.

For those with lactose intolerance, you can choose products that are low in lactose or take a lactase supplement.

Where is milk sugar or lactose sugar found?

Lactose is found in the milk of all mammals, such as cows, goats, sheep, and humans, and it is also found in many prepared foods. The following is a list of the most common substances that contain lactose:

the milk

Let’s start with milk, the main food in which lactose is found. This sugar is not only found in cow’s milk but in all of the milk we usually consume. In this regard, a rumor is circulating that says that goat or sheep milk contains less lactose than cow’s milk. Nothing could be more wrong. Look at the average lactose content in different types of milk (values ​​per 100 grams of product):

  • Goat milk 4.7 g
  • Sheep’s milk 5.2 gr
  • Buffalo milk 5.1 gr
  • Pasteurized cow’s milk 4.9 gr


Whey is the liquid portion that is separated from the milk during the curdling process to convert it into cheese. This product is a real bomb for those with lactose intolerance, as this sugar is actually between 50% and 70% of its content.


Milk contains less lactose than milk. The lactic yeasts that cause milk to turn into milk are actually bacteria that feed on the lactose in milk. Its activity produces waste products that acidify the milk, causing it to be converted into milk.


Finally we get to the cheese. We have a nice surprise for those with lactose intolerance. In fact, there is a long list of cheeses that contain little or no lactose. In addition, cheese contains the least amount of lactose. The bacteria responsible for cheese production feed on the lactose in milk. The more time she has, the more lactose she can digest. Therefore, aged cheese contains very little lactose.

If you are not sure what lactose is in cheese, there is one thing you can do, read the product label. Lactose is the only source of cheese carbohydrates. Therefore, if the cheese contains few carbohydrates, it will also contain little lactose.

Lactose as an additive

So far we have seen that lactose is mainly found in dairy products. But not only that, this sugar is often used in other foodstuffs. Therefore, it can be found in some foods that were not expected. Here are the main ways to use it as follows:

  • Food coloring
  • Sweetener instead of sugar
  • An ingredient in some types of medicines


How do you know if an industrial packaged food contains lactose? Again, read the label, as the law in most countries requires manufacturers to clearly indicate if a product contains allergens such as gluten or lactose.


Now you now know the most important types of foods that contain the sugar lactose and you can find out by reading the label on any food product, in fact, most old cheeses contain a little lactose.

Symptoms of lactose intolerance

Signs of this problem usually appear 30 minutes and two hours after consuming any food that contains lactose. The severity of symptoms depends on each condition, the amount of food, and the degree of insufficiency of the enzyme lactase in the stomach.

It should be noted that the advanced symptoms of this condition are not always specific to it. Thus, it can be combined with other diseases or diseases of the digestive system (mainly acute gastroenteritis).

But in most cases the time at which the symptoms appeared can serve us in determining the cause, if the symptoms appeared shortly after consuming milk, yogurt, cheese or ice cream. It is more likely to be due to lactose intolerance.

Lactose fermentation by the action of intestinal bacteria produces acidic stools that can cause irritation and a burning sensation when defecating. Lactose fermentation can also cause pain, bloating, and greater amounts of gas (which stays for several hours after consuming dairy products).

Feces and flatulence may have a strong and unpleasant odor.

Diarrhea or constipation can occur along with lactose intolerance, as the intestinal flora becomes imbalanced. Stomach cramps or cramps are also very common.

In children or adolescents with lactose intolerance, symptoms of nausea or vomiting are common.

In chronic cases (lactase deficiency),:

  • Significant weight loss.
  • Redness around the anus.
  • Abdominal cramps.
  • Impulsive defecation.

In addition, these patients suffer from skin problems, extreme fatigue, and pain in the extremities.

How do you discover and diagnose a case of lactose intolerance?

If we think we have this problem, it is imperative that we see a specialist. The specialist will carry out various studies that will allow him to diagnose the condition.

The most commonly used tests are:

Measurement of glycemic response

  • The blood is analyzed first to find the initial blood glucose level.
  • Then the patient receives an overdose of 50 g of lactose every 30 minutes for 2 hours (4 doses).
  • After that, another blood sample is obtained to determine the amount of glucose.
  • If the indicators are equal, then it is because lactase does not behave well.

However, this test is not very specific, since there are other diseases that can alter blood sugar, such as diabetes.

Measuring hydrogen in the breath

It is the most widely used method for screening for lactose intolerance.

When the sugars in milk are not digested and go into the intestine, bacteria use them as food and produce hydrogen.

Therefore, if the breath contains a good amount of this ingredient, it is likely due to a problem with the digestion of dairy products.

Small bowel biopsy

The samples needed for this study are obtained through esophageal or gastrointestinal endoscopy. Later, these portions of intestinal tissue are analyzed in the laboratory to confirm the presence or absence of lactase in the mucous membrane.

Stool acidity

This test is mostly used on young children because other studies are impractical or risky at an early age.

Genetic testing

The aim of this evaluation is to detect the primary lactose intolerance caused by the MCM6 gene. A sample of the patient’s blood or saliva is sufficient to analyze two forms related to this condition.