According to the former director of pediatrics at Johns Hopkins University, Dr. Frank Oski, there is evidence to indicate that up to half of U.S. children have some allergic reaction to milk. For these kids (and for adults who are allergic to dairy foods), milk is a mucus maker and can lead to persistent problems such as chronic coughs and sinus infections, asthma, and ear infections.

Noted M.D. and author, Dr. Christiane Northrop, states: "Dairy is a tremendous mucus producer and a burden on the respiratory, digestive, and immune systems." Dr. Northrup says that patients who "eliminate dairy products for an extended period and eat a balanced diet … suffer less from colds and sinus infections."