SHEEP MILK ALLERGY
Key Allergens
Sheep milk by-products are commonly consumed in Western Europe, mostly cheese made from sheep milk like feta and ricotta.
The allergenic proteins in sheep milk are generally split into albumins (commonly called whey) and casein. In human milk the split is usually 60% whey to 40% casein. In sheep milk the split is 20% whey to 80% casein. This is a very similar composition to cow's milk. This massive difference in composition is thought to be the cause of what causes IgE allergic reaction to mammalian milk, with most people being allergic to casein proteins in the milk.
Most sheep milk products are not suitable for those suffering from cow's milk protein allergy. Sheep milk remains a dairy product and is best avoided for those allergic to cows milk.
Sheep milk and cheese still contains lactose and is not suitable for those suffering from lactose intolerance.
The allergenic proteins in sheep milk are generally split into albumins (commonly called whey) and casein. In human milk the split is usually 60% whey to 40% casein. In sheep milk the split is 20% whey to 80% casein. This is a very similar composition to cow's milk. This massive difference in composition is thought to be the cause of what causes IgE allergic reaction to mammalian milk, with most people being allergic to casein proteins in the milk.
Most sheep milk products are not suitable for those suffering from cow's milk protein allergy. Sheep milk remains a dairy product and is best avoided for those allergic to cows milk.
Sheep milk and cheese still contains lactose and is not suitable for those suffering from lactose intolerance.
Food Intolerances
Sheep milk is not suitable for those who are intolerant to lactose. Lactose is a sugar found in milk and dairy products. After it is eaten it is broken down by the body into two digestible sugars. If you are intolerant to lactose it means that your body does not make enough of the enzyme lactase which breaks down the sugars. The gastrointestinal symptoms of lactose intolerance are caused by the body being unable to succesfully breakdown the sugars which cause bloating, discomfort and diarrhoea.
Lactose is a FODMAP food. FODMAP stands for Fermentable oligosaccharides, disaccharides, monosaccharides and polyols. Foods high in FODMAPs can cause symptoms of food intolerance, affecting the gastro intestinal system and this can be mistaken for a true IgE food allergy.
You can read more about Food Intolerances on the dedicated Food Intolerance Page.
Associated Syndromes
Cross Reactivity
Cow, goat and buffalo milk could all be cross reactive with sheep milk due to similar composition.
Resources
Websites
Allergen Encyclopedia - Sheep Milk
British Dietetic Association - Milk Allergies
Anaphylaxis Campaign - Milk Allergies
Articles and Journals
Sheep cheese allergy in Alpha-gal Syndrome, 2023
Food Allergy to Sheep's Milk Proteins with Cow's Milk Tolerance in an Adult Patient, 2023
Managing food allergy: GA2LEN guideline 2022
Immunoglobulin g as milk allergen, 2022
Adult-onset sheep’s milk allergy in a patient without cow’s milk allergy, 2020
Allergy to goat and sheep milk without allergy to cow's milk, 2006
Selective allergy to sheep's and goat's milk proteins, 2004
Cross-reactivity between milk proteins from different animal species, 1999
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