What is lactose intolerance?

Lactose intolerance is the inability to digest lactose, the naturally occurring sugar found in dairy products. In the gut, lactose, a disaccharide requires the enzyme lactase to be broken down to the monosaccharides galactose and glucose. If levels of the lactase enzyme are low or absent, unabsorbed lactose is fermented by the colonic bacteria producing hydrogen and methane gases and small organic molecules. These can cause a number of problems, such as abdominal pain, flatulence, bloating and diarrhoea.

Lactose intolerance does not involve the immune system and so is completely different to cow’s milk protein allergy.

There are two types of lactose intolerance, primary and secondary. Primary intolerance is when the body does not produce much lactase and this occurs over time and begins from infancy. The rate at which lactase production is reduced is genetically determined. This explains why the prevalence of lactose intolerance varies among different ethnic groups, especially Asian, African and Hispanic people. Lactose is most common in certain ethnic groups where their traditional diets over the years have not contained much lactose so their digestive systems have lost the ability to produce much lactase.

Secondary intolerance occurs when the gut lining becomes damaged and does not produce lactase. Thissi often a temporary intolerance following bouts of gastroenteritis, remission stages of Crohn’s and Coeliac disease etc.

The prevalence of lactose intolerance

The prevalence of lactose intolerance varies widely among ethnic backgrounds and is more associated with adults. Approximately 65% of the human population has a reduced ability to digest lactose after infancy. Lactose intolerance in adulthood is most prevalent in people of East Asian descent, affecting more than 90% of adults in some of these communities. Lactose intolerance is also very common in people of West African, Arab, Jewish, Greek, and Italian descent.

The prevalence of lactose intolerance is lowest in populations with a long history of dependence on unfermented milk products as an important food source. For example, only about 5% of people of Northern European descent (including the UK) are lactose intolerant. Within Europe, this condition is most common in Finland, where it affects an estimated 1 in 60,000 new-borns. 

The prevalence of lactose intolerance of a country varies significantly. We can expect that with the increasing number of emigration from East, African and Arab countries, the prevalence of lactose intolerance will increase in Europe. But a good average is between 2 to 15%. In the UK, the prevalence is approximately 5%.

Prevalence of Primary Lactase Deficiency in Various Ethnic Groups

GroupPrevalence (%)
Northern Europeans2 to 15
American whites6 to 22
Central Europeans9 to 23
Indians (Indian subcontinent)
   Northern20 to 30
   Southern60 to 70
Hispanics50 to 80
Ashkenazi Jews60 to 80
Blacks60 to 80
American Indians80 to 100
Asians95 to 100

Adapted with permission from Sahi T. Genetics and epidemiology of adult-type hypolactasia. Scand J Gastroenterol 1994;29(Suppl 202):7-20.

How to avoid lactose in the diet

People can react to lactose in different ways and have different tolerance levels; whilst some people can tolerate a small quantity of lactose others need to remove it from the diet altogether. For anyone sensitive to lactose, it's generally recommended that they start by cutting out all sources of lactose from their diet and then to gradually reintroduce small amounts to determine tolerance levels.

All Alpro plant-based products (drinks, desserts, plant-based alternatives to yogurt, plant-based alternatives to cream, ice-cream) are naturally free from lactose. Additionally, all Alpro non-organic variants are fortified with calcium and vitamin D.

What’s the difference between lactose intolerance & milk allergy?

An allergy involves a reaction by the immune system, while a food intolerance does not - although sometimes the symptoms can seem similar. 

In the case of cow milk protein allergy (CMPA), the cow's milk protein is the allergen provoking the immune system to react, which in some people can be extremely severe and can be life threatening.

In the case of lactose intolerance it is the low level or lack of the enzyme lactase that results in the inability to digest lactose.

Whether someone has lactose intolerance or CMPA, Alpro products provide a great alternative to dairy, as they're all naturally free of lactose, do not contain cow’s milk protein and the non-organic variants are fortified with calcium and vitamin D.