The unlikely, invisible driver behind the miracles: bacteria. Over the past several years, research on the bugs that live on and inside our bodies has exploded. As the health savvy are becoming increasingly aware, we have at least 10 times as many single-celled bacteria floating around in us as human cells, and the majority of these roughly 100 trillion critters are located in the gut—mostly in the colon, where they play an essential role in human digestion. (Without them, we couldn't break down the plant fiber we eat.) Much of the research has focused on how the microbiome might affect what can go wrong in the gut—for instance, in digestive disorders such as IBS or in obesity—because bacteria affect how food is broken down and converted into energy. But one of the hottest areas of research, and arguably the most fascinating, is the connection between gut bacteria and our mental health.
We've known forever that our emotions affect our digestive systems, as anyone who's had a sour stomach before a work presentation has gathered. What these new accounts tell us is that the brain-to-gut effect works in the opposite direction, too. More significantly, they introduce bacteria as a compelling, previously unconsidered player that can communicate, directly or indirectly, with our brains to determine our moods and, perhaps, our most basic sense of who we are. Some scientists now talk about the gut-microbiome-brain axis.
Believing in a gut-microbiome-brain axis repositions the purpose of food from human nourishment to nourishment for the microscopic ecosystem inside us. Brogan starts virtually every patient who walks into her office on a 4-week, one-size-fits-all therapy: Eat only organic, non-GMO, unprocessed foods, with no grains, no dairy except eggs, and no alcohol or coffee. Lots of vegetables is key. And so is fat: olive oil with its monounsaturated fats; wild fish with its omega-3 fatty acids; and, more controversially, plenty of meat (pasture-raised, of course) with its saturated fat and major load of vitamins and minerals.