Knowing if a person is lactose intolerant can be complicated, because although there are apparent symptoms, these are not enough to diagnose lactose intolerance.
For this reason, we spoke with Dr. Agustín Molins, specialist in nutrition and dietetics at Clínica Dr. Molins, to learn a little more about lactose intolerance and how we can identify the symptoms that can alert us to consult a professional.
What is lactose intolerance?
Lactose is the main sugar naturally contained in milk. It is also found in milk derivatives, such as yogurt and cheeses, and accompanying medicines as an excipient component and in many ultra-processed foods.
The body uses an enzyme called lactase to break down lactose into glucose and galactose, which are easily assimilated in our body. In this sense, lactose intolerance is a deficit of the enzyme lactase. When we do not produce enough lactase, the function of transforming lactose into glucose and galactose cannot be developed. Then, a series of symptoms appear, which we will see below.
How does it develop?
The causes of lactose intolerance are due to lactase enzyme deficiency. They are varied and we classify them in:
- Congenital: Its cause is a mutation in a lactase gene. This makes it inoperative and it cannot develop its function when lactose is ingested. It is very rare and newborns with this mutation have diarrhea from the first exposure to breast milk. They will have to avoid lactose for life.
- Primary or racial: There is a progressive loss of the ability to produce lactase and therefore, it is increasingly uncomfortable to drink milk and dairy products. When symptoms appear, it evolves progressively and permanently. It is called racial, because it is more frequent in African-Americans, in whom it can appear from 2 years of age.
- Secondary or acquired: It is usually caused by intestinal damage, either in processes of acute bacterial enteritis, surgical intervention or oncological treatments, among other causes. Once the episode is over, normal function can be recovered in a few weeks, although sometimes the process may become chronic.
What is the incidence of lactose intolerance?
Worldwide, it is estimated that 75% of the population has difficulty digesting the lactose contained in milk and its derivatives. This incidence varies geographically. African Americans and Asians have a higher incidence, reaching more than 90% of the population. In contrast, the incidence in northwestern Europe in countries such as Holland, Norway or Belgium is not close to 5%.
In Spain, an incidence of between 19 and 28% is estimated, but we must take into account that the onset of the disease is progressive and therefore, there are many cases that started their lactase deficit, but are still asymptomatic. If we take into account the people who have already started the decrease in lactase production, we are approaching figures above 50%.
Lactose intolerance can vary with age and, although children can suffer from it at an early age, it is more frequent that with age, our capacity to synthesize lactase decreases and with it, the symptoms appear.
It is important to note that lactose intolerance is different from milk allergy. When we talk about allergy to milk and milk derivatives, we are talking about an immunity problem that makes us allergic to milk proteins, not to the sugar it contains.
What symptoms can indicate a case of lactose intolerance?
Between 30 minutes and a couple of hours after drinking milk or milk derivatives, a picture of discomfort usually appears with:
- Abdominal distention
- Colicky abdominal pains
- Diarrhea
- Gas and flatulence
- Nausea and vomiting
This group of symptoms should be an alert to consult a health professional so that he/she can diagnose the intolerance and guide us correctly.
How long does the intolerance last, is it chronic or temporary?
Congenital lactase deficiency is chronic and lasts a lifetime. Primary lactase deficiency involves progressive deterioration from the age at which it appears and is maintained for the rest of life. However, acquired intolerance usually lasts a few weeks, even a few months, but is recoverable with proper treatment.
Thus, acquired intolerance is temporary, while congenital and primary intolerance are chronic.
Which dairy products have the most lactose?
Condensed milk has the highest lactose content. Whole cow’s milk, par excellence, has the highest lactose content in foods that are not very processed; skimmed milk has slightly less. It is followed by fresh cheeses, yogurts and a wide variety of cheeses.
However, on the other side of the table, with very low lactose content, we can find cheeses such as Gruyère, which is practically lactose-free. Cheddar, Idiazabal, Parmesan Reggiano, the famous Tête de Moine (monk’s head), Camembert, cured Manchego cheese, mature goat cheese and authentic buffalo Mozzarella are practically lactose-free because they lose practically all of their lactose during the production process.
It is important to see, in the labeling, that they contain the D.O. (denomination of origin), because there are many “falsified” cheeses in the market. They are cheeses that usually have less than 3% lactose in their composition and that, in small quantities and accompanied by another food, are usually well tolerated.
Regarding cheeses, in general, we should know that the more fatty cheeses are, the less lactose they contain. The more mature the cheese, the lower the amount of lactose, even practically disappearing as in Gruyère. Cheeses made from goat’s milk have a lower lactose content.
What recommendations can you give us for people suffering from this intolerance?
First of all, go to a health professional to establish the relevant diagnosis. Three tests are performed:
- Lactose-hydrogen breath test
- Lactose tolerance test
- Stool pH test
Once diagnosed and other pathologies with similar symptoms have been ruled out, foods rich in lactose should be eliminated from our diet.
We should consider two options: chronic and irreversible intolerance and temporary intolerance. To begin with, in both situations we should minimize the lactose in our food. While in the first one it should be for life, in the second one, it usually reverts in a few weeks and we can go back to taking lactose from milk and dairy derivatives.
We can resort to taking lactase, the enzyme that we lack, through tablets when ingesting dairy products. This will prevent clinical symptoms of intolerance.
We must learn to find hidden sources of lactose. Many processed and ultra-processed foods contain it. It is easy to find it in beer, sliced bread, soups, sauces, sausages, some condiments, candies, industrial bakery products, etc. They are often used to improve palatability or to better preserve these foods.
We must not forget that many medicines use lactose as an excipient because of its properties for preserving medicines. In this case, the amount is very small and does not usually cause any problem.
Soy yogurts, coconut or almond drinks or lactose-free milk, which do not contain lactose, can be consumed.
Another option is to use lactose-free or lactose-free foods. These are dairy foods to which lactose has been added and has already gone through its digestive process.
In any case, the reduction of lactose-containing foods from the diet can cause deficits of calcium and Vitamin D, Riboflavin and protein. These deficits can be compensated by taking nutritional supplements or obtaining them from other food sources such as broccoli, spinach, almonds and peanuts, thus avoiding a deficit of these nutrients.