What Your Microbiome Wants for Dinner

Let’s admit it. Few of us like to think, much less talk about our colons. But you might be surprised at the importance of what gets into your colon and what goes on inside it. This little-loved part of our bodies is actually less an onboard garbage can and more like the unlikeliest medicine chest.

There is abundant medical evidence that diet greatly influences health, and new science is showing us why this is so. It is also showing us that advocates of trendy paleo and vegan diets are missing the big picture of how our omnivorous digestive system works.

Your colon is the home for much of your microbiome—the community of microbial life that lives on and in you. In a nutshell, for better and worse, what you eat feeds your microbiome. And what they make from what you eat can help keep you healthy or foster chronic disease.

To gain an appreciation of the human colon and the role of microbes in the digestive tract as a whole, it helps to follow the metabolic fate of a meal. But, first, a word about terms. We’ll refer to the digestive tract as the stomach, small intestine, and colon. While the colon is indeed called the “large intestine,” this is a misnomer of sorts. It is no more a large version of the small intestine than a snake is a large earthworm.

The stomach might better be called a dissolver, the small intestine an absorber, and the colon a transformer. These distinct functions help explain why microbial communities of the stomach, small intestine, and colon are as different from one another as a river and a forest. Just as physical conditions like temperature, moisture, and sun strongly influence the plant and animal communities that one sees on a hike from a mountain peak to the valley below, the same holds true along the length of the digestive tract.

How is it that the bulk of what humanity now eats could undermine our health?

Imagine you are at a Fourth of July