How Not to Age: The Scientific Approach to Getting Healthier as You Get Older

by Michael Greger

The primary role of dietary fiber may be to encapsulate nutrients to deliver them to our gut microbiome. Fiber is the brick that builds the cell walls of plants, and those cell walls act as indigestible physical barriers. So, when you eat structurally intact plant foods, some of the nutrition remains trapped. You can chew all you want, but you’ll still end up with nutrients like starch completely surrounded by fiber, delivering sustenance to your friendly flora. Your good gut flora then get to eat not only the fiber but all the food it’s wrapped around, too. Fiber supplements like psyllium, however, fail to carry any bounty to our bacteria and aren’t even fermentable themselves, so we may miss out on all the auxiliary benefits high-fiber diets give your microbiome.