Dairy foods and many protein supplements contain casein and/or whey, proteins the body has difficulty digesting that often results in not only a significant loss in nutritional value but also gastrointestinal discomfort and, in some cases, serious immune responses. There are large amounts of protein (primarily casein and whey) in dairy products such as milk, cheese, yogurt, and ice cream as well as in popular protein powders and meal replacement drinks. This dairy protein provides essential amino acids, particularly tryptophan, lysine, cysteine and branched chain amino acids, for use by the body in optimizing health.[1,2] Research has also discovered properly-digested dairy protein produces a wide variety of peptides, some with immune-modulating, antibacterial, antiviral, antihypertensive, apoptosis, opioid, mineral-binding and/or antioxidant bioactivities. The digestibility of dairy protein determines not only the nutritional value of the food or supplement but also the body’s ability to tolerate it.[2,4] Intolerances to casein and/or whey, which are often mistaken for an intolerance to dairy lactose, can cause gastrointestinal distress such as bloating, nausea, abdominal pain, and/or diarrhea and, in some cases, more serious immune responses.