Lactose Intolerance (Milk Sugar Intolerance)

What is lactose (milk sugar)?

Milk sugar (lactose) is a natural component of milk and a so-called disaccharide sugar, i. e. it consists of two separate monosaccharides – glucose and galactose. For milk sugar to be absorbed in the small intestine, it must first be broken down into these two components. Usually the enzyme lactase (beta-galactosidase), which is found in the mucosa of the small intestine, breaks down milk sugar.

What is lactose intolerance?

Persons who are intolerant to lactose cannot break down milk sugar into its separate components. A lactase deficiency reduces the ability to break down sugar. As a result the milk sugar remains in the bowel, binds water, and ultimately causes diarrhoea. In addition, intestinal bacteria digest the unsplit sugar, causing flatulence.


The majority of the world’s population is not able to completely digest milk sugar after infancy. In other words, lactose intolerance is normal in those cases. Moreover, the sugar splitting enzyme is hardly ever found in Asians. You will therefore not find any milk or cheese products in the diets of people from Asian regions. In Central Europe an estimated amount of more than 15 % of the population suffers from lactose intolerance. Milk sugar intolerance must not be confused with an allergy to dairy products.

There are different types of lactose intolerance:

Primary lactose intolerance This is the most frequent type of lactose intolerance. It is congenital and found most of all in warmer, sunny regions. It occurs from around the age of five and becomes worse with age. Consequently 70 % of Europeans aged 60 cannot digest lactose.

Secondary lactose intolerance This is not a genetic defect, but a disorder of the intestinal mucosa. The enzyme lactase is formed in the epithelium of the small intestine. This layer of the intestine is the first to be damaged by other diseases or external influences. Such influences include taking antibiotics for a longer period of time, for instance. This form of lactose intolerance is reversible, i.e. it can be cured.

Depending on the remaining beta-galactosidase activity in the above described groups of consumers suffering from lactose intolerance, there are significant differences in the amount of lactose that can be tolerated. The advice given by the German Nutrition Society (DGE) takes this fact into account. As a result the majority of persons intolerant to lactose are free of symptoms if they keep to a diet low in lactose (8 – 10 g per day). Very sensitive persons are advised by the DGE to limit lactose consumption to a maximum of 1 g per day. Individuals suffering from galactosaemia, however, should follow a diet practically free of galactose and also free of indirect galactose sources such as lactose.

How much lactose can be found in food?

  • Milk chocolate: 9.5 g/100 g
    equals 2.9 g per portion (portion size 30 g)
  • Ice cream (milk-based): 6.7 g/100 g
    equals 8.4 g per portion (portion size 125 g)
  • Milk: 4.7 g/100 ml
    equals 11.8 g per portion (portion size 250 ml)
  • Latte Macchiato: 4.1 g/100 ml
    equals 6.2 g per portion (portion size 150 ml)
  • Yoghurt: 3.2 g/100 g
    equals 4.8 g per portion (portion size 150 ml)
  • Chocolate spread: 1.9 g/100 g
    equals 0.3 g per portion (portion size 15 g)
  • Camembert cheese (50 % FDM): 0.1 g/100 g
    equals 0.03 g per portion (portion size 30 g)
  • Emmentaler (45 % FDM): < 0.05 g/100 g
    equals < 0.05 g per portion (portion size 30 g)

Source: Souci/Fachmann/Kraut "Food Composition and Nutrition Tables", 7th revised and completed edition (April 1st, 2008), Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart


The position paper created in 2005 by the LChG (German Food Chemical Society) working group “Fragen der Ernährung” (Issues Relating to Diet), which included specifications for “low-lactose”, “very low lactose” and “lactose-free”, has been revised. As a result of new scientific findings and legal circumstances, as well as the current market situation (strong growth of lactose-free products in various product groups), the “Fragen der Ernährung” working group has collaborated with the “Milch und Milchprodukte” (Milk and Dairy) working group to revise the position paper. The current position paper will replace its older counterpart and give marking recommendations for foodstuffs which are not subject to legal guidelines.

Requirement for dairy products to be marked as “lactose-free” in Germany

Lactose content: below 0.1 g/100 g

Recommendation for marking lactose content in foodstuffs

In revising the 2005 position paper, the marking for a content of ≤ 0.1 g of lactose per 100 g or ml of ready-to-eat foodstuffs will be changed to “lactose-free” in order to bring the marking into line with the products in accordance with dairy legislation. The term “low-lactose” is not defined in food legislation.

Recommendation for products including those for people with lactose intolerance

Content Labelling Use
≤ 0.1 g lactose/100 g or ml
of ready-to-eat foodstuffs
“lactose-free” all foodstuffs
>0.1 and ≤ 1 g lactose/100 g or ml
of ready-to-eat foodstuffs
“low-lactose” Foodstuffs for special medical purposes;
foodstuffs for general consumption
excluding dairy products

The marking should show the relevant indication “lactose content: below 0.1 g/100 g or 100 ml” or “lactose content: below 1 g/100 g or 100 ml” or an equivalent specification identical in content.

Recommendation for marking galactose content in foodstuffs

Recommendation for products including those for people with galactosaemia

Content Labelling

≤ 0.005 g simple or bonded galactose*/100 g or ml of ready-to-eat foodstuffs

*“simple galactose” means monosaccharide galactose, while “bonded galactose”
describes the bonded galactose molecule in disaccharide lactose.
For example, a value of ≤ 0.005 g of “bonded galactose” is equivalent to a
value of ≤ 0.010 g of lactose without “free galactose”