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Useful facts on milk allergy (melk)

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Milk allergy

Useful information concerning milk allergy – NAAF’s fact sheet

What is milk allergy?

In cow’s milk allergy, the body’s immune system overreacts to milk proteins either by producing allergy antibodies (IgE), or by activation of inflammatory cells. Every time food containing milk proteins is eaten, the immune system reacts allergically, resulting in release of mediators such as histamine, or by a T-cell mediated inflammatory response. Histamine is released from several areas of the body and causes symptoms such as diarrhoea, vomiting, stomach pains or skin reactions (urticaria, eczema).

Cow’s milk contains over 25 different proteins which can cause reactions in individuals allergic to milk. Most are allergic to several of these. Milk from other mammals such as goats, horses and buffalo contain many of the same proteins, such that most individuals allergic to cow’s milk have to avoid milk from other mammals.

During breastfeeding, cow’s milk proteins from the mother’s diet can be transferred to the child via breast milk. The mother must therefore often also follow a milk-free diet.

Cow’s milk allergy must not be confused with lactose intolerance, which is caused by a reduced ability to digest milk sugar/lactose. Lactose intolerance causes stomach pains and diarrhoea after high consumption of lactose-rich milk products, such as sweet milk, brown cheese, ice cream and cream.


The symptoms suffered by those with cow’s milk allergy vary amongst individuals. They may be mild and harmless for some, whilst for others even small quantities of milk can lead to a severe allergic reaction. Gastrointestinal symptoms are quite common, whilst tingling/itching in the mouth and throat, swollen mucous membranes and breathing difficulties are not quite as common, but do occur, particularly in small children. Flare-ups of eczema and urticaria are most common in small children.

Who does it affect?

Milk allergy is the most common allergy in small children, due to the fact that cow’s milk is a foodstuff which is often introduced in the infant’s diet at an early stage.

Approximately 2-3% of Norwegian children (0-3 years) have cow’s milk allergy.

Diagnosis of milk allergy

The most important tool in diagnosing milk allergy is the patient’s medical history. If there is a suspicion of milk allergy, a prick test and blood test are taken to see whether the body has formed antibodies (IgE) against cow’s milk proteins. Not everyone with a milk allergy has indications from these tests; this applies in particular to infants with symptoms such as vomiting, diarrhoea or blood in faeces. The only certain method to find out whether milk is causing these symptoms is to eliminate milk from the diet, to see if the symptoms disappear. If there is any doubt, milk can be re-introduced, to see if the symptoms return. In children that have not consumed milk for a long period, a controlled provocation with cow’s milk should be done to evaluate whether the allergy has disappeared.


Cow’s milk allergy generally has an extremely good prognosis. Most people grow out of the allergy before school age. For infants with non-IgE mediated allergy (negative allergy tests), one can often try to re-introduce milk as early as after six months to 1 year. Exactly how many people have a milk allergy at an adult age is unknown; however, it is estimated to be well under one percent of the population.

Where do you find milk protein?

Milk is an ingredient in many ready-made meals and industrial food products. It is therefore important to always read the list of ingredients when purchasing food. Where an ingredient is produced from milk the manufacturer must state this in the declaration of contents. The following is a selection of words used in ingredient lists and which identifies that the product contains milk protein:

Crème fraiche, cream, ice cream, casein, caseinate, milk curds, whey protein, margarine, whey, whey powder, cheese, powdered cheese, sour cream, butter, yoghurt, yoghurt powder.

Cocoa butter, lactic acid and E-substances do not contain milk protein.


Milk is an important source of nutrients in the Norwegian diet. 25% of children’s protein intake, 70% of iodine and approx. 70% of calcium comes from milk products. When milk products are eliminated, it is therefore to replace it with foodstuffs that provide the same nutrients. Alternatively, dietary supplements must be used.

What can replace milk?

Drinks: It is recommended thatsmall children (0-3 years old) should use a hypoallergenic milk substitute from a pharmacy. These are available as a blue prescription from a doctor if cow’s milk allergy is diagnosed. As it can be difficult to get older children accustomed to these milk substitutes due to the taste, it is recommended to begin using these as early as possible, preferably at the same time as breastfeeding.
Soya milk and oat milk are recommended for older children and adults. The calcium content in these products corresponds to that in cow’s milk; however, they often contain fewer proteins and trace elements.

In food preparation: Cow’s milk substitute from a pharmacist should be used in the milk-free porridges available from a health food store, or if making porridge yourself from meal. For family mealtimes, soya, rice or coconut milk can be used.

 - Other substitute products: Milk-free margarines, sour cream, yoghurt, ice cream and cream substitutes based on soya, rice and oat milk are available.