Lactose intolerance is a common digestive problem that can cause bloating, nausea and abdominal pain after consuming food and drinks containing lactose.
Symptoms typically develop within a few hours of eating or drinking, and are caused because the body is unable to digest lactose properly.
What is lactose?
Lactose is a type of sugar which is most commonly found in milk or dairy products.
What are the symptoms of lactose intolerance?
Those who have an intolerance to lactose often suffer with uncomfortable digestive symptoms, says the NHS.
These symptoms may include:
wind (flatulence)diarrhoeaa bloated stomachstomach cramps and painsstomach rumblingfeeling sick
The severity of symptoms, and when they appear, depends on the amount of lactose you have consumed.
Some people suffer discomfort after just a small amount of lactose, such as milk in their tea or coffee.
Others may be able to consume more before symptoms are triggered.
Lactose is a type of sugar which is most commonly found in milk or dairy products (Photo: Shutterstock)
What causes lactose intolerance?
Lactose intolerance is caused when the body is unable to produce enough lactase - the enzyme needed to digest lactose.
The enzyme breaks lactose down into two sugars - glucose and galactose - which can be easily absorbed into the bloodstream.
However, people with a lactose intolerance don't produce enough of this to be able to break it down properly.
This means lactose stays in the digestive system where it is fermented by bacteria.
It results in the production of various gases which cause the symptoms associated with lactose intolerance.
Depending on the reason why the body is not producing enough lactase, lactose intolerance could be temporary or permanent.
Those who have an intolerance to lactose often suffer with uncomfortable digestive symptoms (Photo: Shutterstock)
Is lactose intolerance an allergy?
An intolerance to lactose is not the same as a milk or dairy allergy.
Food allergies are caused by the immune system reacting to a certain type of food, triggering symptoms such as a rash, wheezing and itching.
If you have an allergy to something, even a small particle can be enough to trigger a reaction.
Most people with lactose intolerance are able to consume small amounts of lactose without experiencing any problems, although this varies from person to person.
How is lactose intolerance treated?
There is currently no cure for lactose intolerance, but symptoms can be managed by cutting down on food and drink that contain lactose.
Consuming lactose-free versions of food products such as yoghurt, cheese and milk is also recommended.
Your GP may also advise taking calcium and vitamin D supplements, along with lactase substitutes to help improve your digestion of lactose.