Cows’ milk protein allergy or lactose intolerance?

Key takeaways

• Key differences between lactose intolerance and cows’ milk allergy
• Differences between allergies and intolerances
• Speak to your healthcare professional for a confirmed diagnosis

Although they can share similar symptoms, cows’ milk protein allergy and lactose intolerance are two completely different conditions. It is easy to confuse them, but they affect the body in entirely different ways. 

Food allergies, unlike intolerances, involve the immune system. Cows’ milk protein allergy is a food allergy, which means that the immune system overreacts to the protein present in cows’ milk.¹ To avoid a food allergy reaction, it is important to avoid consuming the offending food protein. 

Lactose intolerance is the inability to digest the sugar in milk, which is called lactose.^2,3 It is due to a deficiency of the enzyme (lactase) that is responsible for digesting lactose in the body.  A food intolerance occurs in the digestive system and unlike food allergies, the immune system is not involved.^2,3 Symptoms such as bloating, abdominal pain, flatulence, or diarrhea can be signs of lactose intolerance.^2,3 The skin and respiratory tractare not usually affected. 

As with cows’ milk protein allergy, the symptoms of lactose intolerance can be managed by avoiding foods containing lactose. The main sources of lactose in the diet are usually cows’ milk and dairy products. To ensure adequate calcium and protein intake it is important to substitute these foods with calcium-containing alternatives. Fortunately, lactose-free milk and dairy products are available in most supermarkets. 

It is important to see your child’s healthcare professional if you are worried or not sure about your child’s symptoms. 

This article and the Symptoms Checklist are not intended to be a substitute for medical advice. Always consult your doctor.

References accessed 11th June 2021: 

1. Australasian Society of Clinical Immunology and Allergy (ASCIA). The Immune System 2021. Available from: https://www.allergy.org.au/patients/immune-system (Accessed June 2021) 
2. Australasian Society of Clinical Immunology and Allergy (ASCIA). Cows’ milk (dairy) allergy 2019. Available from:  http://www.allergy.org.au/patients/food-allergy/cows-milk-dairy-allergy (Accessed June 2021) 
3. Dietitians Australia. Understanding lactose intolerance. Available from: https://dietitiansaustralia.org.au/smart-eating-for-you/smart-eating-fast-facts/medical/understanding-lactose-intolerance/ (Accessed June 2021).