Lactose intolerance 

What is a lactose intolerance? 

Lactose intolerance is a reaction from your digestive system when eating dairy products. It can make you feel uncomfortable due to your body’s difficulty in digesting lactose, the sugar found in milk and other dairy foods.

The body generally can’t absorb lactose unless it is broken down into simpler sugars, such as glucose and galactose. This breakdown happens as lactose passes through the stomach into the small intestine and comes into contact with a protein (enzyme) called lactase.

If there isn’t enough lactase in the small intestine, lactose cannot be broken down and absorbed. This is the most common cause of lactose intolerance.

Lactose intolerance vs milk allergy 

A milk allergy is often confused with lactose intolerance, but they are different. A milk allergy is when your immune system reacts to the proteins found in milk, causing inflammation.

This can cause similar symptoms to lactose intolerance, such as diarrhoea, bloating, or gas after consuming milk or products containing milk.

However, a milk allergy also causes symptoms such as wheezing, hives, lips/tongue/throat swelling, rash or even anaphylaxis.

Anaphylaxis may result in death if left untreated. So, if you experience the following symptoms, we recommend you seek emergency medical help immediately:

• A rash
• Shortness of breath, wheezing, or difficulty breathing
• Difficulty swallowing
• Chest tightness
• Drop in blood pressure
• Dizziness or a loss of consciousness

Risk factors

Some people have a higher risk of developing lactose intolerance than others. You may be at a higher risk if you experience the following:

• Increasing age
• Asian or African heritage – studies suggest that primary lactose intolerance affects 80–99% of African and Asian people
• Medical history of digestive problems or diseases
• Premature birth
• Relatives with lactose intolerance
• Certain cancer treatments – such as chemotherapy

Diagnosis

Lactose intolerance is mainly a clinical diagnosis, and tests are generally not reliable and do not play a major role in the diagnosis. We use tests to mainly exclude other conditions that may be mistaken for lactose intolerance.  

During your initial consultation, a specialist will assess your symptoms, family and medical history and may examine your abdomen (stomach). 

If your specialist suspects that you may have lactose intolerance, they may: 

• Request you follow a lactose elimination diet – you will have to stop eating and drinking products with lactose to see if symptoms improve 
• Perform blood tests and stool tests – This helps exclude other conditions which may cause similar symptoms.  
• Perform a hydrogen breath test – if you cannot digest lactose, your gut bacteria can ferment the lactose in your bowel, producing gas such as hydrogen and methane. The breath test can measure the amount of hydrogen and methane gas in your breath when exhaling. 
• Perform gastroscopy or colonoscopy examination with a tissue biopsy – a small sample of tissue can be taken from your bowel. This is rarely done and is typically performed to investigate another condition, such as colitis or coeliac disease. 

If another digestive condition is suspected of causing your lactose intolerance, we will perform the relevant tests to determine whether this may be the cause of your symptoms. 

Treatment

There is no immediate cure for lactose intolerance, but managing your diet and reducing your lactose intake will help alleviate your symptoms. 

Depending on the kinds of dairy products you’re able to eat, you may also require additional calcium and vitamin D supplements to keep your bones strong and healthy. 

Taking lactase supplements can help give your body the lactase it needs to break down lactose. You can take these as tablets or drops before consuming lactose. 

At Digestive Health UK, we partner with expert dieticians to offer tailored treatment options and dietary therapies that are best suited to you and your needs. We will help you on your journey to managing your food intolerance and guide you through your treatment plan. 

If another digestive issue is discovered, we will recommend the relevant treatments to help manage your condition.