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We often hear about the importance of the gut microbiome, and rightfully so. It’s central to a healthy digestive system, nervous system, immune system… basically every body system. But did you know it thrives on a particular type of food? Introducing the concept of a gut superfood… resistant starch.
What is The Role of The Gut Microbiome?
The gut microbiome is made up of bacteria, viruses, fungi, and other microorganisms that live inside the human gut. This is the good gut flora everyone is after. But like any living organism, these beneficial microorganisms need support and nourishment. Otherwise, they aren’t able to fully do their job to protect and promote health. That’s where resistant starch (RS) comes in.
Optimizing the intestinal microbiota with resistant starch can improve many aspects of health. It can improve digestion, elimination, the immune system, hormones, and even the look of our skin! The great thing is that it’s easy to increase our intake. But first, what exactly is resistant starch?
What is Resistant Starch?
We’ve long heard about the importance of including fiber in our diets. We hear about soluble fiber and insoluble fiber and their importance for adding bulk to the stool. Both improve digestion and help balance blood sugar. So how does this relate to resistant starch?
Resistant starch is more fiber-like than starch-like. It’s similar to dietary fiber because it can’t be digested. This starch ends up being low glycemic rather than high, so it also doesn’t spike blood sugar like typical starch would.
The Insitute of Medicine included resistant starch in their definition of fiber in 2002.
Prebiotics For Gut Health
Our bodies don’t digest resistant starch. Instead, it serves as a type of fermentable fiber and works as a prebiotic in the gut. Prebiotics are indigestible substances that pass through our (mostly sterile) small intestine fairly intact.
They go straight to the large intestine, which is where most of our gut bacteria live. Rather than digestive enzymes breaking these starches down, they’re fermented. The good bacteria use them as fuel and multiply.
So, resistant starch basically acts as food for our gut flora. Prebiotics feed probiotics. That’s why you’ll see some probiotic supplements that include prebiotics on their ingredients list. When good bacteria eat prebiotics, it results in the production of “postbiotics.”
Postbiotics and Resistant Starch
One type of postbiotic is short-chain fatty acids (SCFAs). These SCFAs lower bowel pH, which means a less hospitable environment for pathogens. The most crucial SCFA in the intestines is butyrate. Butyrate is the preferred fuel for the cells lining the colon and increasing it has many health benefits.
I talk more about butyrate and the other SCFAs in this article on postbiotics.
Types of Resistant Starch
There are four types of resistant starch:
- RS Type 1 — Starch that’s found in certain plant cell walls, like grains, legumes, and seeds.
- RS Type 2 — Starch that’s rich in the polysaccharide (chain of sugars) called amylose. Amylose is indigestible when raw, so it feeds the gut bacteria. Once cooked, it no longer serves as resistant starch. You’ll find it in raw potatoes, green bananas, plantains, and some legumes.
- RS Type 3 — “Retrograded” resistant starch. It’s made when Type 1 or Type 2 resistant starches are cooked and then cooled. Potato salad and bean salad are excellent sources.
- RS Type 4 — A synthetic form of resistant starch from supplements. One popular commercial version is Hi-maize resistant starch. Hi-maize is a specially processed type of corn starch that’s resistant to digestion. It’s used in fiber drinks and in some baked goods.
Increasing your intake of resistant starch has a wide range of potential benefits. Some you may not notice symptom wise, but others you will. Some results you may not know until you go in to get your cholesterol or glucose levels checked.
Health Benefits of Resistant Starch
For over three decades, researchers have looked at the health effects of resistant starch. You can find both human and animal studies and the results are pretty amazing. Resistant starch may:
- Increase absorption of important minerals like calcium and magnesium.
- Promote gastrointestinal health by providing dietary fiber.
- Decrease absorption of toxic and cancer-causing compounds. This may lower the risk of colorectal cancer or colon cancer.
- Positively change microflora, particularly increasing bifidobacteria, which can ease constipation.
- Support a balanced immune system.
- Lower inflammation in the gut and throughout the body.
- Lower cholesterol and lipid levels.
- Lower the risk of developing heart disease.
- Combat insulin resistance by helping with insulin sensitivity.
- Lower blood glucose levels.
- Increase feelings of satiety.
- Promote weight loss, combatting obesity.
- Lower the risk of metabolic syndrome and type 2 diabetes.
- Improve brain and gut health.
Amazing, right? All of us could use help in at least a few of these areas. So how do we get more resistant starch?
How to Get Resistant Starch in Your Diet
We naturally get resistant starch from the food we eat. The highest sources of resistant starch are raw potatoes, green bananas, green plantains, cooked and cooled potatoes, rice, and beans. You can see a detailed list of resistant starch foods in this chart from Free the Animal.
Many of these foods you may not eat, as they have other negative health effects. But you don’t have to eat bagels and cornflakes to get resistant starch. Healthy foods high in resistant starch include the following:
Resistant Starch Foods
These are all rich in undigestible starches that feed our good bacteria and promote gut health. Most resistant starch studies have participants ingest 30 grams a day. According to the chart linked above, a 200-gram boiled potato can have up to 9 grams of potato starch.
You can boost the resistant starch content by cooking and then cooling the potatoes. That’s known as retrograded starch. If you eat grains and beans, think cold rice salads or re-heated beans with your eggs — that sort of thing. You could even add some homemade hummus. These are a few good ways to create retrograded starch and increase your RS intake.
Starchy foods like cassava and potatoes are also good sources of prebiotics. They’re great to include in your diet to boost prebiotic intake. But when was the last time you had a Jerusalem artichoke? Plus, you’re looking at eating a lot of carbs to reach that target amount of resistant starch. There must be an easier way…
Here’s an Easier Way to Get It
In general, Wellness Mama readers tend to follow a lower carb, traditional, Paleo, or whole foods based diet. So, eating a diet based on starch and grains may not be so enticing.
If that’s the case, try this little hack instead: Consider raw potato starch. Raw potato starch has about 8 grams of resistant starch per tablespoon. It has very few “usable’ carbohydrates. This starch doesn’t affect blood sugar levels, since the body doesn’t digest it. The gut microbiome does.
Raw potato starch is inexpensive and tastes bland, so it’s easy to use. It’s also naturally gluten-free and overall allergen-free. Remember it has to stay raw, so you don’t want to cook it. It’s best to stir it into a cold or lukewarm beverage or add it to uncooked foods.
Where to Find Resistant Starch
There are many good options out there for resistant starch. But these are the ones I’ve personally tried with good results and recommend. My favorite is the prebiotic powder because it tastes delicious!
Start Slow and Watch for Reactions
Of course, consult with your health practitioner before beginning any health regimen. They can give guidance on the right dose for you and discuss any personal health concerns.
It’s also best to start slow. You may want to start by simply eating more prebiotic-rich foods. You can also just add some cooked and cooled potatoes, like in this sweet potato salad. Or, try adding one teaspoon of potato starch to a smoothie, kefir, or water. Slowly build up your dose.
Side Effects of Resistant Starch
A common reaction to potato starch is an increase in gas or bloating. You may also have changes in your stool. These symptoms result from changes in the bowel bacteria. For most people, these side effects are short-lived. If they persist, give yourself a break and stop taking the potato starch.
Instead, work on boosting your existing good bacteria with probiotics, particularly soil-based ones. Then try adding small amounts of potato starch back in and see how you do. Usually, tolerance improves over time.
Final Thoughts on the Benefits of Resistant Starch
Many people who consistently consume resistant starch report improved health. They have better sleep and dream recall. Their bowel movements are more consistent, and they notice improved digestion. Their blood sugar control improves, and they have better muscle tone.
Sounds good to me!
Do you try to include resistant starch in your diet? What’s your favorite way to get it?
- Barko, P. C., et al. (2018). The Gastrointestinal Microbiome: A Review. Journal of veterinary internal medicine, 32(1), 9–25.
- Centers for Disease Control and Prevention. (2022). Fiber: The Carb That Helps You Manage Diabetes. CDC Diabetes Library.
- Kau, A. L., Ahern, P. P., Griffin, N. W., Goodman, A. L., & Gordon, J. I. (2011). Human nutrition, the gut microbiome and the immune system. Nature, 474(7351), 327–336.
- Lamas, A., Regal, P., Vázquez, B., et al. (2019). Short Chain Fatty Acids Commonly Produced by Gut Microbiota Influence Salmonellaenterica Motility, Biofilm Formation, and Gene Expression. Antibiotics (Basel, Switzerland), 8(4), 265.
- Murphy, M. M., Douglass, J. S., & Birkett, A. (2008). Resistant starch intakes in the United States. Journal of the American Dietetic Association, 108(1), 67–78.
- Nugent, A.P. (2005). Health properties of resistant starch. Nutrition Bulletin, 30: 27-54.
- Shiu-Ming Kuo. (2013). The Interplay Between Fiber and the Intestinal Microbiome in the Inflammatory Response, Advances in Nutrition, 4(1), 16–28.