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You Are What You Eat

You Are What You Eat

Or, more precisely, you are what you eat eats. Here we explore the wild and diverse world of your gut microbiome and its critical role in your total body health—from head to toe.

At a recent dinner party to celebrate a friend's birthday, I met a gregarious German woman in her 60s who had just tried one of those DNA testing kits to learn about her family history. "Everyone is doing it," she said, smiling and laughing, speaking in a thick accent. "You just spit into a tube, swoosh it around, and drop it in the mail! Then you receive an email with your results. It's fun!"

I immediately wanted to tell her about the mail-order test-tube kit that I'd just tried, but my husband intervened. "Wait," he said, "people are still eating."

Intestinal bacteria, stool samples, and bowel movements are hardly polite dinner conversation. When the dishes were all cleared, I shared that I'd recently done something similar to those DNA kits, but instead of spitting into a tube, I swabbed a piece of used toilet paper. I was testing my gut microbiome, not only for curiosity but also because I was hoping to collect a few clues about some health issues.

Blank stares suggested I'd better explain that the microbiome is the community of trillions of bacteria and other organisms living in and on us. The majority of those invisible organisms are in our intestinal tract, the gut, where they are capable of influencing virtually every aspect of our health. These microbes are like factory workers keeping the body's operations running smoothly, playing essential roles in digestion, revving up the immune system, protecting us from pathogens, and regulating metabolism. They produce certain important vitamins, including K2, good for strong bones, and folate, key for healthy cell development. They can alter how we store fat and balance sugar levels in the blood. Remarkably, the gut contains some 100 million neurons, specialized cells that transmit nerve impulses—as many as the spinal cord and more than the peripheral nervous system, which means intestinal microbes have a direct line to our body's command center. A "gut feeling" isn't just cliché—many experts refer to the gut as the body's "second brain."