'Dr Staci uncovers a game-changing truth: the mouth is not just the mirror of health, it's the command centre. This book will transform the way you think about disease prevention and longevity.' James Nestor, New York Times bestselling author of Breath

Right now, there are twice as many microbes in your mouth as there are people on the planet. The ecosystem in the average person’s mouth contains 20 billion microbes, around 800 bacterial species, plus yeasts, viruses, fungi and thousands of other microscopic life forms.

And they’re all interacting with each other in one dynamic ecosystem, which affects everything from your mood to your appetite, your heart health, fertility, Alzheimer's risk and your immune system.

Over the last decade we’ve had a cultural obsession with the gut microbiome, but the mouth is the portal by which everything passes to the gut – and it’s anything but passive. The oral microbiome actively communicates with the entire body, so much so that researchers are increasingly seeing the mouth as a diagnostic window into whole-body health.

In Spit, board-certified dentist and oral microbiome pioneer Dr Staci Whitman transforms complex science into a thrilling road trip through our bodies, presenting the new science sharing how ultra processed foods, sugary drinks, polluted air, and chronic stress have crowded our teeth, shrunk our faces, and altered our saliva. She shares how the more diverse our oral microbiome, the better our health outcomes, and she shows how we can make simple changes to our habits to boost that diversity:

• have a breakfast you can chew, rather than sipping a smoothie
• eat the rainbow to feed your microbial menagerie
• understand why bad breath can be an indicator of serious disease
• build your child's oral microbiome from birth

Spit is a fascinating journey into understanding why your mouth matters.

© Staci Whitman 2027 (P) Penguin Audio 2027