Lactose intolerance: Causes, symptoms, and lactose-free foods

s usually caused by a lactase deficiency. Lactase is an enzyme produced in the small intestine which helps to digest lactose.

If your body does not produce enough lactase, food and drink containing lactose will pass through the digestive system into the colon.

Once in the colon, the lactose is broken down by bacteria which produces gasses and fatty acids – and it’s these that trigger the symptoms of lactose intolerance.

There are different types of lactase deficiency:

Primary lactase deficiency

This is the most common cause worldwide, and will usually occur after the age of two when you become less reliant on milk and other dairy products. Primary latase deficiency is genetic.

Secondary lactase deficiency

Secondary can occur at any time, and is often triggered by surgery or certain medication.

It’s the most common cause of lactose intolerance in the UK, and can be a result of other conditions.

These include:

Lactose intolerance symptoms

These will usually occur a few hours after consuming food or drink which contains lactose, such as milk or dairy products.

Symptoms will differ in severity depending on how much lactose you consume, and also from person to person.

They can include:

If you suffer from any of these after consuming dairy products it’s important to book an appointment with your GP to confirm what you are suffering from, and to rule out other conditions including irritable bowel syndrome.

Lactose intolerant diet

After being diagnosed with lactose intolerance you should initially exclude all food and drink containing lactose from your diet.

If your symptoms ease up, then you may be able to reintroduce small amounts of lactose – however some people find they can’t even have milk with their tea and coffee without triggering a reaction.

It’s important you find other sources of vitamins found in dairy products, including calcium and vitamin D.

These foods are calcium rich but dairy-free:

Dairy-free sources of vitamin D:

Lactose-free dairy alternatives

There are a whole range of lactose-free products available, including milk and cheese, from brands such as Lactofree and Alpro.

More information about lactose intolerance can be found on the NHS website.