Lactose Intolerance: What Happens in Your Body When You Can't Tolerate Milk Sugar

Lactose intolerance - what's behind it, and what can you do about it?

Many people know the feeling: after a glass of milk or a yoghurt, your stomach starts rumbling and cramping. Other unpleasant symptoms follow. This could be down to lactose intolerance, also known as milk sugar intolerance. If an enzyme is missing, your body can't tolerate milk sugar (lactose). Read on to find out what the possible causes of lactose intolerance are, which symptoms it comes with, what you can do about it, and what you need to watch out for in your diet if you have a milk sugar intolerance.

Lactose intolerance - what symptoms occur?

More and more people suffer from lactose intolerance. It's one of the most common food intolerances. In Germany alone, around 14 million people live with a milk sugar intolerance. They can't tolerate milk sugar, so eating milk or dairy products leads to significant symptoms, for example:

• Stomach ache
• Bloating
• Nausea
• A feeling of fullness
• Diarrhoea

The typical symptoms of lactose intolerance usually appear 30 minutes to a few hours after eating foods containing lactose. The intensity of the symptoms varies from person to person and depends on the lactose content of the food eaten and the severity of the milk sugar intolerance. A good way to get rid of the symptoms is to stop consuming products that contain lactose. Switching to a diet without milk sugar is often difficult at first, but there are now plenty of substitute products available.

Everyone's tolerance threshold for lactose is different. Some people affected can tolerate foods with a little milk sugar, while others can't. There are lactase tablets: if you have a milk sugar intolerance, you take these shortly before eating, which also makes it possible to eat products containing milk sugar.

Besides this, subtle symptoms can occur that aren't usually linked to lactose intolerance, for example:

• Headaches
• Dizziness
• Chronic tiredness
• Exhaustion
• Trouble concentrating
• Low mood

Lactose intolerance - what happens in your body with a milk sugar intolerance?

The reason for the symptoms that many people with lactose intolerance suffer from after eating milk or dairy products is as follows: their body isn't able to process milk sugar, a component of milk. The enzyme lactase, which is needed for this, is missing in them, because their body doesn't produce it, or doesn't produce enough of it. This digestive enzyme's job is to split milk sugar into two single sugars so that the gut is able to process it further. But in people with a milk sugar intolerance, this doesn't happen. The milk sugar isn't broken down.

It ends up in the large intestine. Countless microorganisms live here, bacteria above all, which process the milk sugar and, through fermentation, produce gases such as methane, carbon dioxide and hydrogen, which are among the things that cause the symptoms of lactose intolerance. As a result, the gases make the stomach bloat. This leads to strong, cramp-like flatulence. Lactose also binds water, so more and more of it flows into the large intestine. This means the gut fills up quickly, so the stool becomes watery. The bacterial breakdown of the lactase also produces organic acids, which speed up bowel movements. The result is diarrhoea and cramps.

Please note: a milk allergy is not lactose intolerance!

With a milk allergy, it's the milk protein that causes the problems, not the lactose. It triggers immune reactions in the body which, if severe enough, can even be life-threatening. Milk protein allergy and lactose intolerance must therefore never be confused with each other.

Where is milk sugar found? What should you watch out for with lactose intolerance?

Milk sugar is found in a great many foods, especially in milk: 100 millilitres contain almost five grams. Whether you drink cow's, sheep's or goat's milk, it's always the milk sugar that matters.

Besides this, lactose is also found in many other foods, for example:

• Cheese
• Quark
• Butter
• Yoghurt and pudding
• Cream
• Ice cream
• Ready meals like pizza with cheese

The substance is even found in some toothpaste and medications.

Different forms of lactose intolerance - primary and secondary milk sugar intolerance

Primary lactose intolerance

Primary milk sugar intolerance is congenital and leads to a gradual decrease in lactase production. The primary form, which is the most common, is therefore genetic. Very rarely, the enzyme deficiency can already become noticeable in childhood, although the typical symptoms usually only show up in adulthood. The reason: in childhood, enough lactase is still produced, while this process steadily declines with increasing age, so the intolerance to milk sugar becomes greater and greater.

Secondary milk sugar intolerance

Secondary lactose intolerance occurs as a result of damage to the mucous membrane of the small intestine. It's encouraged by various illnesses and other factors, for example:

• Coeliac disease: this is an inflammatory bowel disease triggered by a misdirected immune reaction of the body to gluten (a binding protein) found in various types of grain.
• chronic inflammation of the intestinal mucosa, such as Crohn's disease
• other chronic inflammatory bowel diseases, some of which are caused by medication
• bacterial infections can also encourage a milk sugar intolerance
• fungal infections such as a candida infection
• surgery in the gastrointestinal area

Further factors can also cause secondary lactose intolerance, for example:

• other intolerances such as a fructose intolerance
• prolonged use of antibiotics, which have a very negative effect on the gut environment and destroy healthy gut flora
• medications such as cytostatics, which are used, for example, as a chemotherapy drug for cancer, or for autoimmune diseases or rheumatoid arthritis, also have a disruptive effect on gut health
• Chemotherapy and radiotherapy
• Alcohol abuse

The mucous membrane of the small intestine is able to regenerate. This means secondary lactose intolerance can improve again once the underlying condition has been successfully treated.

How can lactose intolerance be diagnosed?

To identify a milk sugar intolerance, doctors have various options available, besides talking to the patient, which often already provides good clues. One of the most important methods is the hydrogen breath test: here, the breakdown of lactose by bacteria produces a very large amount of hydrogen. This is breathed out by your body and is therefore used to diagnose milk sugar intolerance. If the body doesn't metabolise the lactose properly, the bacteria in the large intestine produce hydrogen, which reaches the air you breathe out and can be measured there. In addition, blood sugar levels are checked after regularly giving milk sugar, since these barely change in people with lactose intolerance.

If you suspect you might have a milk sugar intolerance, it's best to keep a symptom diary. You can also try eating a lactose-free diet for several days to see whether the symptoms go away. A blood sample analysed in a genetics lab can be used to detect genetic milk sugar intolerance.

What can you eat and drink?

• Lactose-free dairy products
• Fruit and vegetables, as well as fruit and vegetable juices
• Jam and honey
• Coffee and tea
• Rice, pasta and potatoes
• Pulses and grains
• Unprocessed meat
• Poultry
• Fish
• Eggs
• Nuts

You can eat all vegan products without any worries. With lactose intolerance, you should pay particular attention to getting an optimal calcium supply.

Summary

Lactose intolerance is a very widespread food intolerance. It shows up through various digestive complaints that occur after eating dairy products. The body isn't able to digest milk sugar properly. The primary form is congenital, and secondary milk sugar intolerance is acquired over the course of life through illnesses or other factors. Once the underlying condition has been overcome, lactose intolerance can improve again. As a general rule, you should make sure you relieve your gut with a lactose-free diet.

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