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Resistant Starch and the Low FODMAP Diet

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When most people think of starch, they think of easily digestible carbohydrates best avoided or limited on a healthy diet — I’m talking about white bread, pastries, cakes, etc. These are the foods we intentionally stay away from when we’re looking to feel well and reduce our risk of chronic disease.

However, not all starches are created equal. In fact, there’s a type of starch that, despite its name, we shouldn’t resist. It’s called resistant starch. We don’t eat enough resistant starch, even though it’s good for us.

In this article, we’ll define resistant starch, review common food sources, and discuss its health benefits, with an emphasis on gut health. Then, we’ll show you how you can eat foods with resistant starch on a low FODMAP diet

What is Resistant Starch?

Technically, resistant starch is defined as “the starch fraction that escapes digestion in the small intestine of healthy humans.” As its name suggests, it resists digestion by human enzymes and travels to the large intestine (i.e. large bowel or colon) where it can serve as fuel for the gut microbiota. More on this later. 

There are 4 key types of resistant starch, classified as RS1-4. RS1 and RS2 are found naturally in foods, whereas RS3-4 results from food processing. I’m highlighting these classifications because you might come across them at some point, but they’re inconsequential for most of us because they don’t strongly correlate with health benefits.  

What Foods Have Resistant Starch?

We only find resistant starch in carbohydrates. And while most Americans eat plenty of carbs, our current intake of resistant starch is lower than recommended. That’s because the standard American diet is high in carbs that are low in resistant starch, such as French fries, potato chips, cookies, rice, sugary breakfast cereals, most bread, and most pasta. 

We’re not eating enough foods high in resistant starch, including: 

  • Cooked legumes, such as lentils, split peas, and chickpeas
  • Cooked beans, including pinto, white, black, lima, and kidney 
  • Cooked and cooled starchy foods, such as cooked and cooled pasta, rice, and potatoes (e.g. potato salad)
  • Uncooked oats, cooked and cooled oats  
  • Green bananas 
  • Whole or partly milled grains and seeds
  • Corn tortillas 

Curious why green bananas are better than yellow for upping resistant starch intake? Why uncooked oats versus cooked oats? Why potato salad over freshly cooked potatoes? Great questions! 

How much resistant starch ends up in food depends on the cooking method, storage time, and serving temperature. For example, chilling cooked foods, such as potatoes, greatly increases resistant starch content. 

 

Health Benefits of Resistant Starch 

Resistant starch benefits our health in several ways, with the greatest impact on gut health and metabolic health. 

Resistant Starch and Gut Health

As mentioned earlier, resistant starch escapes digestion in the small intestine and travels to the large intestine, where it’s available to feed beneficial gut microbes. 

We humans might lack the enzymes to break down resistant starch, but our commensal microbes are well-equipped for the job. When microbes feed on or ferment, resistant starch, they produce beneficial by-products, such as butyrate.  

Butyrate is a short-chain fatty acid that supports gut health via several mechanisms. Studies have shown butyrate can… 

  • Lower intestinal pH, discouraging the growth of pathogenic bacteria 
  • Increase the uptake of important minerals, such as calcium
  • Inhibit absorption of potentially toxic or carcinogenic compounds 
  • Provide energy to colon cells
  • Strengthen the gut barrier 
  • Protect against colon cancer and inflammatory bowel diseases 

Besides supporting the growth of beneficial microbes and the production of butyrate, resistant starch can add bulk to stool, which can lead to more regular bowel movements. Added bulk can help those with constipation and/or diarrhea. 

Resistant Starch and Systemic Health

The potential health benefits of resistant starch extend beyond the gut to the rest of the body.

Studies have shown resistant starch can increase insulin sensitivity, lower blood glucose, and promote satiety. These findings suggest a role for resistant starch in protecting against diabetes and obesity. 

Plus, the gut microbiota affects every aspect of our health. Resistant starch has the potential to positively alter our glut flora and increase SCFA production, leading to a decreased risk of a variety of chronic diseases. I love the phrase “genetics loads the gun, but the environment pulls the trigger.” By consuming more resistant starch (an environmental factor), we might have the potential to change our gut flora to reduce our risk for a disease we’re genetically predisposed to get.

 

How To Eat Resistant Starch On A Low FODMAP Diet? 

OK, so hopefully you’re convinced it’s a good idea to eat more foods with resistant starch. Now you might wonder how to up your intake of resistant starch on a low FODMAP diet. 

Many people, particularly those with IBS, feel better when they steer clear of high FODMAP foods because FODMAPs are rapidly fermented in the presence of bacteria. The most obvious result of this fermentation process is intestinal gas, which can lead to symptoms of abdominal pain, bloating, and distension.

Here’s some good news… Unlike FODMAPs, microbes slowly ferment resistant starch in the large bowel. This leads to a more gradual build-up and release of gas over time, which is less likely to contribute to IBS-type symptoms. 

Here are some sources of resistant starch to consider on a low FODMAP diet: 

  • Uncooked oats, ½ cup. I love adding uncooked oats to my smoothies. Soak them in your liquid base in your blender while you prepare the rest of your ingredients. Or, try overnight oatmeal, like this one from Fun Without FODMAPs
  • Unripe or underripe banana, 1 medium. Unripe bananas are higher in resistant starch and lower in FODMAPs than ripe bananas. How convenient! Don’t you love when things work out this way?
  • Potatoes, cooked and cooled. Consider trying a cold potato salad, like this one from FODMAP Everyday
  • Cooked lentils, ½ cup. Lentils are an excellent source of resistant starch but pay close attention to portion size. 
  • Brown rice pasta, cooked and cooled. Top with your favorite low FODMAP toppings to make a pasta salad. 
  • Canned chickpeas, ¼ cup. Top your salad or soup with canned chickpeas for a quick dose of resistant starch. Just be mindful of portion size. 

 

References

Birt DF, Boylston T, Hendrich S, et al. Resistant starch: promise for improving human health. Adv Nutr. 2013;4(6):587-601. Published 2013 Nov 6. doi:10.3945/an.113.004325

Miketinas DC, Shankar K, Maiya M, Patterson MA. Usual Dietary Intake of Resistant Starch in US Adults from NHANES 2015-2016. J Nutr. 2020;150(10):2738-2747. doi:10.1093/jn/nxaa232

Murphy MM, Douglass JS, Birkett A. Resistant starch intakes in the United States [published correction appears in J Am Diet Assoc. 2008 May;108(5):890]. J Am Diet Assoc. 2008;108(1):67-78. doi:10.1016/j.jada.2007.10.012

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About Author

Colleen D. Webb, MS, RDN
Colleen D. Webb, MS, RDN

Colleen Webb, MS, RDN, is a registered dietitian and nutritionist with extensive experience in counseling patients with complex gastrointestinal conditions. She created the nutrition education program for patients, doctors, dietitians, medical students, and dietetic interns at the Inflammatory Bowel Disease Center at Weill Cornell Medicine in New York City, as well as The Ultimate Online Training Education for Registered Dietitians Treating IBD Patients — approved for 10 CPEUs by the CDR. Colleen runs a virtual private practice and is an adjunct professor at New York University where she teaches the graduate-level “Diseased Gut” course.

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