What is resistant starch?

Resistant starch (RS) is a type of starch that is not broken down by human digestive enzymes, and it is therefore considered a dietary fiber.^[1] Starch occurs naturally in plants as a storage form of glucose. Upon consumption, some starch is quickly broken down into glucose molecules that can be absorbed into the bloodstream, but RS resists digestion and absorption in the small intestine and travels to the large intestine where it can act as a food source for microbes of the gut microbiota — particularly via bacterial fermentation.^[2] Bacterial fermentation of RS in the large intestine leads to the production of compounds capable of influencing human health — most notably short-chain fatty acid (SCFAs), like butyrate.^[3] While intriguing, the research on RS in humans has been mixed and inconsistent, and it’s not entirely clear how RS influences the gut microbiome or general health.