Casein is the main structural protein in cow’s milk and is present in cheese, yogurt, milk, cream, ice cream, and many processed foods. The Casein marker on the 1019 IgG Food Antibodies – Bloodspot panel measures IgG antibodies directed against casein proteins. IgG antibodies indicate immune recognition following exposure. They do not diagnose lactose intolerance (which involves difficulty digesting milk sugar) and do not diagnose an IgE-mediated milk allergy.
Casein is heat-stable and remains present in many dairy products, particularly cheese. Because dairy is frequently consumed, mild to moderate IgG responses may reflect regular intake rather than clinically meaningful intolerance. The relevance of the result depends on whether symptoms consistently follow dairy consumption and improve when casein-containing foods are removed from the diet.
Some individuals with elevated casein IgG levels report delayed symptoms such as bloating, abdominal discomfort, diarrhea or constipation, fatigue, headaches, sinus congestion, skin conditions (including eczema or acne), or joint discomfort after consuming dairy. These symptoms are typically delayed and may occur hours to a day after ingestion.
Casein
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