People with a true milk allergy are usually allergic to the proteins in dairy and will react to even a small amount of these foods. Elimination from the diet is usually recommended as symptoms can be life-threatening.
Food allergy signs and symptoms
Food allergy can develop at any age, but is most common in young children aged less than five years. Nine foods cause 90% of food allergic reactions, including cow's milk, egg, peanut, tree nuts, sesame, soy, fish, shellfish and wheat. Symptoms of a true food allergy develop following exposure to an allergen and can include: hives; swelling of the lips, eyes or face; vomiting; or wheeziness. Anaphylaxis is the most severe form of allergic reaction and can be life-threatening.1
Cow's Milk Allergy
In Australia and New Zealand around 2% (one in 50) babies are allergic to cow's milk and dairy products. Most children outgrow cow's milk allergy by the age of four and ongoing symptoms in adults are very rare.2
Diagnosis and diet
Skin-prick allergy tests or allergy blood tests by a clinical immunology/allergy specialist help to confirm or exclude potential triggers of an allergic reaction. People with a true milk allergy are usually allergic to the proteins in dairy and will react to even a small amount of these foods. Once an allergy has been diagnosed by a doctor, the offending food or foods should be eliminated from the diet.
If cow's milk is the allergy identified, avoid all foods that contain:
- Cow's milk;
- Cow's milk products, including cheese, yoghurt, ice-cream, butter, ghee, buttermilk, cream, and cream fraiche; and
- Cow's milk ingredients, such as milk powder, milk solids, casein and whey.
People who are allergic to cow's milk are allergic to all types of cow's milk (regardless of milk brand or type of cow) and are often allergic to the milk of other animals such as goat's milk. If long term exclusion is necessary, patients require an alternative source of calcium and protein, and advice from an Accredited Practising Dietitian should be sought.
The difference between intolerances and allergies
It is important to distinguish an allergy from an intolerance.
Lactose intolerance is caused by the lack of the enzyme lactase, which helps to digest the milk sugar lactose. The symptoms can include diarrhoea, vomiting, stomach pain and gas, which are similar to some of the symptoms of milk allergy.3 This condition is uncomfortable but not dangerous, and does not cause rashes or anaphylaxis.4 Small amounts of cow's milk are usually tolerated, and yoghurts and hard cheeses are often tolerated, as they contain less, or easier-to-digest, lactose.5
Learn more about Lactose Intolerance and treatment options.
How long should cow's milk be avoided
As milk allergy is usually outgrown, it can often be successfully reintroduced under medical supervision. This can be done by repeat allergy testing. Reintroducing an eliminated food into a child's diet must be done extremely cautiously and only under strict medical guidance.6, 7
What are the consequences of eliminating dairy from the diet
Apart from being the biggest contributor of calcium in the Australian diet,8 cow's milk provides a unique package of other essential nutrients including protein, riboflavin, vitamin B12, vitamin A, potassium, iodine and phosphorus.
Removing a food group, such as dairy, from the diet should be done with the assistance of an Accredited Practising Dietitian to make sure all nutritional needs are still being met. Not consuming dairy foods risks insufficient dietary calcium intake and has been known to result in reduced bone mineral density and increased incidence of fracture.9
Milk alternatives include calcium-enriched legume/bean/cereal milk products such as calcium-enriched soy, rice and oat drinks. Fortified alternatives should contain at least 100mg of added calcium per 100ml. Soy (except soy follow-on formula) and other nutritionally incomplete plant-based drinks such as rice, oat, coconut or almond drinks are inappropriate alternatives to breast milk or formula in an infant's first 12 months. Fortified soy drink or calcium-enriched plant-based drinks can be used after 12 months of age under health professional supervision, as long as other sources of protein and vitamin B12 are included in the diet.10
1 Australasian Society of Clinical Immunology and Allergy (ASCIA). Food allergy [Internet]. ASCIA, Balgowlah, 2015. Available: http://www.allergy.org.au/images/pcc/ASCIA_PCC_Food_Allergy_2015.pdf
2 Australasian Society of Clinical Immunology and Allergy (ASCIA). Cow’s milk (dairy) allergy [Internet]. ASCIA, Balgowlah, 2015. Available: http://www.allergy.org.au/images/pcc/ASCIA_PCC_Cows_milk_dairy_allergy_2015.pdf
3 Suchy F. National Institutes of Health Consensus Development Conference: Lactose Intolerance and Health. Ann Inter Med. 2010;152(12):792.
4 Australasian Society of Clinical Immunology and Allergy (ASCIA). Cow's milk (dairy) allergy [Internet]. ASCIA, Balgowah, 2015. Available: http://www.allergy.org.au/images/pcc/ASCIA_PCC_Cows_milk_dairy_allergy_2015.pdf
5 National Asthma Council Australia. Australian Asthma Handbook, Version 1.0 [Internet]. National Asthma Council Australia, Melbourne, 2014. Available: http://www.asthmahandbook.org.au/clinical-issues/food/healthy-eating
6 National Health and Medical Research Council. Australian Dietary Guidelines, Canberra: Commonwealth of Australia; 2013.
7 Australasian Society of Clinical Immunology and Allergy (ASCIA). Cow's milk (dairy) allergy [Internet]. ASCIA, Balgowah, 2015. Available: http://www.allergy.org.au/images/pcc/ASCIA_PCC_Cows_milk_dairy_allergy_2015.pdf
8 Australian Bureau of Statistics [Internet]. Canberra: ABS; 2015. Australian Health Survey: Usual Nutrient Intakes, 2011-2012. Cat 4364.0.55.008. [updated 2015 Apr 27; cited 2016 Feb 09]. Available: http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/4364.0.55.008~2011-12~Main%20Features~Calcium~401
9 Weaver CM. Should dairy be recommended as part of a healthy vegetarian diet? Am J Clin Nutr. 2009;89(5);1634S–37S.
10 National Health and Medical Research Council. Australian Dietary Guidelines, Canberra: Commonwealth of Australia; 2013.