Lactose intolerance: when your stomach rebels

Every day for the last six months or so, a patient has suffered from pain and rumbling in her lower stomach that only ends once it’s completely empty. She rarely meets up with friends anymore, preferring to stay at home and take it easy. Eventually, things got so bad that she had to go to the doctor.

“The patient was scared. The doctor asked her to keep a diary of her symptoms. This way they discovered that she was lactose intolerant.The flatulence usually occurred one to three hours after eating, and the symptoms – cramps, diarrhoea, vomiting – worsened over the course of the day.”  Brigitte Baru is a dietician who works at the aha! Swiss Allergy Centre. She looks after patients in the university hospital, answers queries on the centre’s advice hotline and gives training courses on nutrition, for example for restaurateurs.  

Who is most affected by lactose intolerance?

Lactose intolerance may be the most common food intolerance in Switzerland, but it came as a surprise to the 40-year-old patient. “It's no wonder! Anyone who has drunk milk with no problems all their life doesn’t immediately think they may be lactose intolerant,” says Baru. “But it can occur suddenly at any age. It often happens after a bowel infection when you may have had to take antibiotics.”

Genetics also play a role. In fact, people around the world tolerate dairy products to varying degrees. In Asia, nine out of ten people show an adverse reaction to lactose. You’ll rarely find milk on the menu there. In Europe by contrast, 80 to 90% of people have no problems with lactose. “Intolerance is increasing as a result of globalisation and mixing of the global population,” explains Baru.  

But why do some people, – we are higher mammals after all – tolerate lactose of all things so badly? “As adults, we’re no longer actually supposed to drink milk. However, our bodies have adjusted to the intensive livestock farming and high milk consumption throughout history.”

What is lactose intolerance?

The sugar in the milk of mammals is called lactose and consists of galactose and glucose. Normally the lactose in the small intestine is split into its two components by the enzyme lactase so that they can be absorbed into the blood through the intestine. However, some people suffer from a lactase deficiency, either due to heredity or caused by an illness. Instead of entering the bloodstream, lactose reaches the large intestine undigested and is fermented there by bacteria. This fermentation process causes pain and problems with digestion.  

Getting diagnosed  

More and more people believe they’re lactose intolerant. Is it really true or just their imagination? “It’s true that we’ve been getting a lot of inquiries about this lately,” confirms Baru. “People today are better informed when it comes to their diet. This means they’re able to pinpoint their symptoms more easily than a few years ago. In the past, people suffered a lot longer without saying anything.”  

However, she’s sceptical about self-diagnosis, because there are many other diseases in the intestinal tract that the general public aren’t familiar with. “You should always consult an expert.” Otherwise you may suffer unnecessarily for years. “Nowadays we use nutrition diaries and diet to find out how much lactose a person can tolerate. For example, some people don’t notice the effects until after their third milky coffee,” says Baru.   

Not all tests are the same  

After talking to the doctor, being tested is a sure-fire way of finding out whether you’re lactose intolerant or not. However, there are major differences between tests. Although blood and genetic tests show whether you’re predisposed to lactose intolerance, they don’t provide any information on whether you actually are lactose-intolerant or not. The H2 breathing test is the only way to really know where you stand. In this test, the patient takes lactose in a controlled manner and records their symptoms in a log book. After three hours, the amount of hydrogen in their blood is measured. However, as this test is time-consuming and costly, it’s no longer offered in many places.   

Eating healthily despite lactose intolerance  

“You don’t have to include cow’s milk and dairy products in your diet,” says Baru, “There are many plant-based alternatives available today that are healthy, particularly if they’re enriched with calcium and vitamins.” In fact, Baru says with a laugh, if you’re going to develop an intolerance, lactose intolerance is the best one to have. There are even many dairy products available today without lactose. “These contain an enzyme that breaks down the lactose.”   

Today, many people who are lactose intolerant don’t have to go without. But you’ve got to be careful if you’re eating out or relying on ready meals, because you’ll find lactose hidden in virtually every meal. Whether it’s in the sauce, spice mix or mashed potato, small quantities are often added to change the taste, colour or volume of the food on offer.   

Consequences of lactose intolerance  

What happens if lactose intolerance goes untreated? Do you shorten your life expectancy by subjecting your intestine to permanent stress? Are you at risk of bowel cancer? “There’s no need to worry”, says Baru. “The intestinal mucosa is not affected. It doesn’t get inflamed or change in any way. Once the lactose has gone, everything returns to normal.”