Dr. Perlmutter is a board-certified neurologist and a fellow of the American College of Nutrition (ACN). He also has a clinic in Naples, Florida, and he's been very active in publishing his findings in peer-reviewed medical journals.

His previous book, Grain Brain, topped the New York Times bestseller list for 54 weeks. In my view, Dr. Perlmutter is probably the leading natural medicine neurologist in the US.

Certainly, most neurologists fail to consider how lifestyle impacts the neurological disorders they diagnose and treat every day, and prevention is an area of utmost importance as we still do not have effective treatments for many of the most common brain disorders.

"We're now recognizing from research at our most well-respected institutions from around the globe that the gut bacteria are wielding this very powerful sword of Damocles," he says.