There are several types of protein found in cow's milk that fall
under three distinct types. Caseins, beta-lactoglobulin and
alpha-lactalbumin. These proteins include an array of enzymes,
proteins for nutrient transport, antibodies, and growth
factors.
Casein itself has been linked to the promotion stage of cancers
in many studies. (See the China Study for more information.) Also,
whey proteins ( ß-lactoglobulin and a-lactalbumin) typically aren't
fully digested in the intestines and can lead to localized
intestinal and systemic immune responses.