Dairy Intolerance could be caused by a sensitivity to one of two main proteins in cows milk, whey and casein. Other milks, such as goat or sheep milk could also act as trigger foods. Eggs can also be responsible for food intolerance reactions, both the egg white which is primarily protein, as well as the more fatty (but tasty!) yolk.
Manifesting as bloating, Irritable Bowel Syndrome (IBS), weight gain, fatigue, skin problems, migraines or joint pain, even a mild food intolerance to dairy or eggs may have a major impact upon a person’s day to day activities, and the inclusion of these foods in a western diet is so common that the actual intolerances can be difficult to find, and also to avoid successfully.
Smartblood Story - Julia's Intolerance to Dairy