Feed your GUT army the right stuff: Resistant starch

Building beneficial gut bacteria through probiotics requires consistent intake of the appropriate food sources.

John Bagnulo June 11, 2025

Most Americans get too much of their overall carbohydrates from sugars and not enough from resistant starch. Rice and peas, especially when cooled to some extent, are among the best sources of resistant starch. This type of resistant starch develops in a process called retrogradation when certain glucose-rich foods cool after cooking. Other examples include potatoes, sweet potatoes, and buckwheat. Resistant starches come in varying degrees of complexity, but all offer gut bacteria an important food source. Bacteria that produce the essential short-chain fatty acid n-butyrate are considered among the most essential microbial families to human health. These microbial armies drive the fermentative conversion of carbohydrates to short-chain fatty acids. N-butyrate is a vital source of fuel for our brain and other organs; it is used by the cells that line our intestinal tract to build and repair, it lowers the pH of our gut, which is very beneficial, and it is anti-inflammatory as well. The families of bacteria known as n-butyrate producers typically need resistant starch to survive and maintain population levels that generate this essential energy source for much of our physiology.

Most of us typically consume a diet low in resistant starch but high in carbohydrates. Refined carbohydrates typically foster pathogenic rather than commensal species, such as Clostridium species and C. difficile. Populations eating refined, processed foods have repeatedly been shown to have less of the helpful bacteria and more of those associated with chronic disease. It’s also at a point where gut ecologists believe that probiotics are almost pointless if the right food sources are not being presented regularly to these beneficial strains we are trying to build. In addition to resistant starch, peas also contain significant amounts of soluble fiber that support a host of other beneficial gut microbes as well. For those individuals avoiding grains, cereals, and legumes (and there are sound arguments for doing so!), green bananas or plantains are also a great source of resistant starch. Overall, one of the most important principles for establishing gut health is to eat an array of fiber sources. Resistant starches are technically more like fiber than any other type of carbohydrate. We need gut bacteria to break them down, and their digestion is very limited otherwise. Although it is a step in the right direction for many people trying to avoid foods causing health issues, repeatedly eating a source of protein on a salad made of only mixed greens doesn’t foster great gut health.

The message here is “Build it and they will come”!

Consider joining us for 5 days in Sebastian, Florida, this coming February.

February 8-13. Five days with lectures like this by John Bagnulo, cooking classes, and meals I create, all gut-friendly, local, and delicious. We have a lot of fun, and there are opportunities to swim and cold plunge, ride bikes, and learn about biodynamic farming practices.

This one-dish meal is perfect this time of year. Yes, it is super gut-friendly and healthy, but more importantly, it is delicious. It is a great do-ahead meal—served at room temperature. Compliment it with cucumber or asparagus soup (last week's recipe!). And …because it is asparagus and radish season, I added both to this recipe.

Here is the recipe:

About Shrimp

Opt for wild-caught shrimp whenever possible. Farmed shrimp pose risks to your health and the environment, including pollution, habitat destruction, resource depletion, and potential health risks for humans due to the use of chemicals and antibiotics in farming practices.

Most restaurants and markets serve farmed shrimp. Over 90% of shrimp consumed in the U.S. is imported and predominantly farmed. What the shrimp consume, you consume. The conditions of farmed shrimp operations and their feed are best avoided. Shrimp farming has a history of significant environmental damage spanning four decades. Wild shrimp is the preferred option. The most sustainable choices include wild-caught MSC-certified pink shrimp from Oregon or spot prawns from the Pacific Northwest and British Columbia, caught using traps.

Avoid purchasing shrimp from India, Ecuador, Vietnam, or Indonesia, as these are typically farmed.

Shrimp offers a lean source of protein and is rich in essential nutrients. It's packed with vitamin B12, which aids in red blood cell formation and nervous system function, and selenium, a mineral that protects cells from damage.