Supplemental digestive enzymes are gaining traction with consumers. Increasingly, when patients show me their multivitamin labels, there are a handful of digestive enzymes listed among the vitamin and mineral ingredients. I’ve also read online testimonials from folks who swear that enzymes marketed as providing “digestive support” for gluten work as promised—and enable them to eat bread and pasta, bloat-free.

What are these enzymes, exactly? Should you be taking them?

Enzymes are proteins that facilitate specific chemical reactions. Digestive enzymes facilitate the chemical breakdown of food into smaller, absorbable components. Enzymes called amylases break down starches into sugar molecules; proteases break down proteins into amino acids; and lipases break down fat into its component parts.

Humans naturally produce multiple different enzymes in these families that encounter food at different places in the digestive process: first in the mouth, then in the stomach, and finally, within the small intestine. Humans also possess disaccharidases, or enzymes that break the bonds between double sugar molecules like sucrose (table sugar) and lactose (milk sugar) into two individual sugar molecules for absorption.

Unlike members of other biological kingdoms, humans (as mammals) lack digestive enzymes that break down compounds from plant cell walls like cellulose, pectins and resistant starches. These dietary compounds are collectively called “fiber.” By definition, fiber is a nondigestible substance whose health benefits derive from its inability to be absorbed. Since it survives the digestive process intact and unabsorbed, it can travel along to the colon where it feeds our resident bacteria and contributes to fecal bulk.

In considering whether taking supplemental digestive enzymes may be beneficial, one should recognize that the term “digestive enzymes” is a catchall that includes a variety of compounds with different purposes—similar to “vitamins” or “probiotics.”