About 30-40% of the world’s population and five million Australians are dealing with food or environmental allergies.

Despite this, not a whole lot is actually known about them, in fact, their definition can’t even be agreed upon.

A new book, Allergic: How Our Immune System Reacts to a Changing World breaks down the complicated way allergies and the immune system work. Guest: Dr. Theresa MacPhail, author