Why avoid lactose ?
As we age, the enzyme that allows us to digest lactose decreases. To the point where some people become intolerant. A logical conclusion would be that consuming dairy products is unnatural for adults. But it’s not that simple.
Lactose is the carbohydrate contained in all milk of animal origin. It is made up of two simple sugars: glucose and galactose. “For glucose and galactose to be absorbed as this form of lactose in the small intestine, we need an enzyme that breaks their bond,” deciphers Nicolas Mathieu, gastroenterologist at the Grenoble University Hospital. The human organism produces one of these enzymes: lactase. But not always in sufficient quantities.
“At birth, the infant has optimal lactase activity. Then, over time and with dietary diversification, the lactase activity decreases. And that’s where there’s going to be differences, depending on the individual, depending on the region of the world.” explains Brigitte Coudray, a dietitian nutritionist at the Centre de recherche de l’information nutritionnelles de l’interprofession des produits laitiers (Cerin).
When is lactose intolerance suspected ?
If lactose passes through the small intestine without being – or not completely – absorbed, it then reaches the colon, where it will ferment because of the specific intestinal flora of this section of the intestine. The result is swelling, pain, acid diarrhoea, or vomiting in the most severe cases.
The appearance of these symptoms after milk ingestion generally leads to the suspicion of lactose intolerance. However, this can be confused with an allergy to milk proteins. However, several tests can confirm an intolerance.
Once the diagnosis has been made, the health professional will prescribe a strict diet for one month. “All foods that may contain lactose, including cheeses, prepared dishes or industrial pastries will be banned to suppress the symptoms,” says Nicolas Mathieu. After one month, we will try to reintroduce foods where there are traces of lactose: dry cheeses, cookies, etc. And we continue the reintroduction to find the tolerance threshold, so that the patient can have the most varied diet possible.” Because each lactose intolerant has his own tolerance threshold. Moreover, the majority of French people, who are small milk drinkers (about 100 ml per day according to Brigitte Coudray), never reach it!
When you can’t drink milk at all
But some people are lactose intolerant to the point where they cannot consume milk at all. “They can consume other dairy products, replace milk with yogurt or cheese,” says Brigitte Coudray. Nothing can totally replace the calcium intake of dairy products: they provide at least 50% of our daily needs. And other foods contain very little. You would have to consume kilos of fruit and vegetables to compensate. ”
As dairy products are the subject of endless controversy, Dr. Nicolas Mathieu does not entirely share this opinion: “Some people will be so embarrassed that after the month of exclusion, they won’t be able to go back up to the next level. They must therefore take products as a replacement, and be very careful about calcium intake. The recommended dose is 1200 mg/day for men over 65, and otherwise 900 mg/day. So it’s possible to get enough calcium, but by taking higher doses of other foods that provide it, such as certain waters and vegetables.”
No lactose free diet
However, Nicolas Mathieu does not recommend a lactose-free diet except in cases of intolerance. This would risk causing decalcifications, osteoporosis, and therefore fractures. “Moreover, we don’t yet know the consequences that a lactose-free diet can have on the intestinal microbiota,” says Dr. Mathieu. But if we modify the richness or variety of this flora, it seems that we favour certain diseases such as diabetes. Such a modification can induce in some patients too violent interactions with the intestinal proteins, and lead to chronic inflammatory bowel disease (IBD)”.