22 Mar 2024 Article

Lactose intolerance is one of the most common food intolerances in the world. It is estimated that as many as three quarters of the world’s population are lactose intolerant.

Some facts about lactose intolerance

Did you know that:

  • Lactose intolerance and milk allergy are not the same.
  • Only one in three adults can digest lactose.
  • Most people with lactose intolerance can eat hard cheese without having any complaints.
  • Sheep’s milk and goat’s milk are equally high in lactose as cow’s milk.

Lactose intolerance is very common

Lactose intolerance is one of the most common food intolerances in the world. It is estimated that as many as three quarters of the world’s population are lactose intolerant. This is because most people produce little to no lactase. Lactase is the enzyme that our body needs to break down lactose. However, people with lactose intolerance can eat some dairy products without any problems, as long as those products don’t contain too much lactose. For example, hard cheese types. But a glass of milk, which does contain a lot of lactose, should not be drunk by these people, because they will get cramps, a bloated stomach and/or diarrhea.

What is lactose?

Lactose is a carbohydrate, a milk sugar, a disaccharide. “Di” in the word “disaccharide” refers to the number two”. Lactose is composed of two monosaccharides (single saccharides), namely glucose and galactose.

What is lactase deficiency and how is it connected to lactose intolerance?

There are two major types of lactase deficiency: primary and secondary. Primary lactase deficiency, also referred to as lactase-nonpersistence (LNP), is genetically determined and is a normal, developmental phenomenon characterized by the downregulation of lactase enzyme activity. In other words, with age, your body produces less and less lactase. It is most common in people from Africa and Asia, but anyone can have it. In adults with LNP, undigested lactose reaches the colon where it can elicit symptoms of lactose intolerance.

Secondary lactase deficiency is usually a short-term phenomenon. It is due to illnesses that affect your small bowel such as coeliac disease, inflammatory bowel disease (IBD), gastrointestinal infections (food poisonings) or abdominal surgery.

What is lactose intolerance?

If you have lactose intolerance, it means that you cannot digest lactose from food properly because there is none/too little of the enzyme lactase in your small intestine. Because lactose is not or insufficiently broken down into glucose and galactose, lactose ends up undigested in the large intestine. The bacteria in the large intestine ferment the lactose, which can cause gas formation and other fermentation products. This can cause abdominal complaints. Lactose also pulls water into the bowel, which is why it can also cause loose stools.

Does lactose intolerance occur in (young) children?

Lactose intolerance is rare in children under 3 years of age. Almost every infant has sufficient lactase at birth to properly digest lactose in breast milk. After the third year of life, lactase production gradually decreases. About a third of the world’s population can continue to digest lactose after the age of three.

What is the difference between lactose intolerance and cow’s milk allergy?

Lactose intolerance and cow’s milk protein allergy are two completely different conditions. Cow’s milk protein allergy involves an unwanted overreaction to the proteins in cow’s milk. This involves an immune reaction, which can cause damage to the intestines and other severe health consequences. With lactose intolerance, the proteins are tolerated, but the undigested lactose once again, (lactose is a carbohydrate) is the cause of the complaints. The complaints are annoying, but not dangerous. With lactose intolerance there is no immune reaction.

How lactose intolerant are Dutch people?

Worldwide, approximately two-thirds of the adult population is deficient in lactase. Interestingly, in the Netherlands this percentage is significantly lower. An estimated 12% of the population has difficulty digesting lactose. The number of people who actually suffer from complaints of lactose intolerance is estimated to be three to five times lower. The Caucasian race, to which most of the Dutch population belongs, has the unique property that lactase activity is maintained throughout life. People of a different ethnicity are genetically programmed in such a way that lactase production decreases after infancy.

How do you find out if you are lactose-intolerant?

The diagnosis of lactose intolerance is usually made using a hydrogen breath test. For people with a mild form of lactose intolerance, this is a good, non-invasive method. There are also lactose tolerance tests, in which a certain amount of lactose is administered, and the blood sugar level is determined. Another option is the elimination diet. This option is best if you don’t feel like visiting a health provider to diagnose possible lactose intolerance.

How does the elimination diet work?

The elimination diet is very easy. You can ask your dietitian to help you with it, or you can just follow the next steps.

First, eliminate all the dairy from your diet for at least four weeks. If you have secondary lactose intolerance, it can take longer.

If after four weeks you don’t notice any significant improvements, your complaints might be due to a different cause. Discuss your problem with your GP or dietitian.

If you do notice significant improvements in how you feel after eliminating lactose for four weeks, it means you most probably have lactose intolerance. If you want to find out your boundaries (I certainly recommend doing so, unless you want to spend the rest of your life without dairy), start to put some lactose back into your diet. Start with a very small amount and increase slowly. Most people can manage some lactose, but everyone has a different limit.

It is recommended to start by trying foods that are lower in lactose such as hard cheese. Try a small amount and increase it gradually. If you don’t experience unpleasant symptoms after consuming low-lactase foods, start introducing foods higher in lactase (see the list below). When you start experiencing bloating/gas/watery stools you know that you’ve found your lactose limit.

Most people can tolerate 12 grams of lactose per meal (or drinking moment), and a total of 20-24 grams spread throughout the day.

Are fermented dairy products and cheese easier to digest for people with lactose intolerance?

Fermented milk products such as yogurt, cottage cheese and buttermilk often contain less lactose than milk. This is because the lactic acid bacteria present in these products have already broken-down part of the lactose.

(Semi)hard cheeses that have been ripened for at least 4 weeks contain less than 0.1% lactose and can usually be eaten without any problems.

Lactose content in foods (per 100 g)

  • Sheep’s milk: 5.1 g
  • Cow’s milk: 4.6 – 4.8 g
  • Goat’s milk: 4.4. g
  • Custard: 4.6 – 5.4 g
  • Yoghurt: 3.6 – 4.7 g
  • Mascarpone: 4.5 g
  • Cottage cheese: 3.5 g
  • Fromage frais: 2.9 – 4.1 g
  • Crème fraiche: 2 g
  • Cream: 1.7 – 2.2. g
  • Haloumi: 1.5 g
  • Feta: 1.4 g
  • Ripe / rind cheeses: 0.9g
  • Hard cheese: 0.1 g
  • Blue cheese: 0.1 g
  • Brie: 0.1 g

Are lactase enzymes helpful?

Lactase enzymes can for sure be helpful for individuals who suffer from symptoms of lactose intolerance. In most countries you can buy lactase enzymes at a drugstore without a prescription.