What is it?

Lactose is a type of sugar mainly found in milk and dairy products. The problems arise when the body is unable to digest it.

Lactose intolerance is a dietary problem where the body is unable to digest lactose. It arises due to lack of an enzyme called Lactase, which is produced by cells that line the small intestine. Lactase breaks down lactose into two simple sugars called glucose and galactose, which can then be easily absorbed into the bloodstream.

When the enzyme production is low, the body in unable to break down lactose and it is this unused lactose that is then digested and fermented by resident bacteria in the colon. It is this fermentation process that causes the symptoms associated with lactose intolerance.

What are the symptoms?

Common symptoms include bloating, diarrhoea, flatulence, abdominal pain or cramps.

Is it a food allergy?

No. An intolerance is not the same as a food allergy. When you are allergic to something, even a tiny amount of it can trigger an allergic reaction. With an intolerance, a small amount will not trigger any reaction or ill effects. However, the amount will differ from person to person.

Primary and Secondary intolerance

Lactose intolerance can be classified as primary or secondary.  Primary intolerance results when enzyme production slows or stops. This is dictated by the gene MCM6 which is responsible for producing lactase.

Secondary intolerance is a temporary intolerance caused by trauma to the gut by infection or certain treatments.

How can we tell the difference?

Genetics can determine if the intolerance is primary or secondary. A simple saliva sample will give a genetic expert the ability to test your genotype for lactose tolerance. Using this information, they will be able to give you advice on whether you should be avoiding dairy and how to structure your diet accordingly.