Resistant starch. What the heck is that? It sounds like something you might spray on your shirt to prevent staining.
Actually, it’s something you want to eat more of because it’s probably one of the most health-promoting food discoveries of the past couple of decades. Resistant starch is truly a miracle food compound that will help you lose weight and have better blood sugar control. In fact it has revolutionized the food industry around the world. Food manufacturers are adding it to foods like pasta, crackers, breads and baked goods to promote weight loss and prevent diabetes. Consuming resistant starch helps reduce the risk of colon cancer, heart disease and obesity. And to think that all this wonderful health promotion takes place in the gut.
What is resistant starch?
Resistant starch is a non-digestible part of fiber that bypasses absorption in the stomach and the small intestine and is fermented by microbes in the large intestine. This process favorably alters the absorption of calories and certain nutrients. Most Americans don’t eat enough resistant starch, only getting about 5 gms a day, while in countries where the diet consists largely of cooked and cooled porridge and beans, the average daily intake of resistant starch is between 30-40 gms.
There are no dietary guideline recommendations for resistant starch but evidence indicates eating more of it can reduce both digestible calories and blood insulin levels. Research also supports:
- Improved insulin sensitivity – this means less work for your pancreas and less circulating insulin. High blood insulin levels are associated to weight gain, diabetes and cancer.
- Improved bowel health – protective against colorectal cancer, diverticulitis, constipation, inflammatory bowel disease, and ulcerative colitis
- Improved blood lipid profile – protective against cardiovascular disease
- Increased feeling of fullness and less calorie intake – helps with weight loss
- Increased micro-nutrient absorption – improves the absorption of minerals, including calcium for bone health
There are discrepancies among countries in how resistant starch is measured; consequently in 2002 the Association of Official Analytical Chemists started recommending a specific in vitro method for consistency of measurement. Not every country follows this recommendation which is why you still see disparities in values.
Four types of resistant starches:
Resistant starch is both a dietary fiber and functional fiber, depending if it is from food or added to food. Its discovery has led the Institute of medicine to define fiber as viscous and fermentable and phase out the former definition of soluble and insoluble. There are four different types of resistant fiber found in foods.
- RS1 – these types cannot be broken down by digestive enzymes. Examples are whole and partly milled grains, seeds and legumes. Milling and chewing increases digestibility but also reduces the amount of resistant starch.
- RS2 – these resist digestion due to their physical nature. Sources include raw potatoes, green bananas, some legumes and high-amylose corn (Hi-maize cornstarch). Cooking and processing reduces them.
- RS3 – these are formed in the process of cooling after cooking. They include bread and tortillas and cooled pasta, rice and potatoes. Processing reduces them.
- RS4 – these are chemical modified starches made to resist digestion.
Structural changes occur in resistant starches with processing, cooking, ripening and temperature, making them more digestible and less beneficial. The advantages of the commercially manufactured resistant starch like Hi-maize, are that they are not affected by processing and storage.
Resistant starch in food
Resistant starch changes with cooking time and food temperature. A roasted potato that has cooled has over 19 gs of resistant starch while a hot baked potato has less than 1 gm. Foods like grains, beans and pasta that are served al dente have much more resistant starch than foods that are cooked longer and are softer.
Unripe fruits and vegetables have more resistant starch than riper ones.
Below is a table of common foods with their respective grams of resistant starch. The higher the number of grams, the better the source of resistant starch. You can look up other foods here, from freetheanimal.com.
Commercial sources of resistant starch
Bob’s Red Mill makes potato starch that you can add to your smoothies or use in baking. And King Arthur makes Hi-maize that you can substitute for part of your flour. They also suggest adding it to soups and sauces to make them creamier.
Increase your dietary resistant starch this way
Good sources of high resistant starch include cooked then cooled potatoes, green bananas, legumes and raw oats. If you plan on increasing your intake begin gradually so your gut can adjust. Below are some ways you could increase your daily intake of resistant starch:
- Serve your pasta and rice al dente
- Instead of a hot baked potato, make cold potato salad
- Make cold grain salads to take for lunch; mix quinoa, tuna and raw veggies with balsamic vinaigrette
- Refrigerate your fruit and veggies to slow ripening
- Instead of canned, prepare your own beans using dry and cook them leaving them a little crunchy.
- Eat bananas that still have a partially green peel
- Prepare your oatmeal or other grain al dente and let it cool before eating.
- Make no-bake chocolate refrigerator cookies! Remember these? They call for uncooked rolled oats.
- Look for pasta, crackers, and breads made with resistant corn starch. They will have fewer carbs and more fiber. That’s a win-win.
It is so refreshing to learn that simple changes in how we prepare and eat food, not another pill, can significantly impact weight and health. And these suggestions won’t interfere with your usual routine. If anything it will save time on cooking, allow you to cook enough for several meals if you choose (like making a pot of oatmeal), and it will save you time.
I have already made some changes in my diet since learning about resistant starch. I had stopped buying bananas years ago thinking they were really high in carbs, but now I will buy and eat them green. In fact, I will top my oatmeal with them. This morning I cooked steel-cut oats, leaving them quite chewy. I added some chia seeds, some dates and ground flax seed and then let in cool before I ate it. Interestingly, I noticed four hours later, my usual stomach growling time, I was still reasonably satiated.
I’m having company tonight and for dessert I’m making rhubarb cake replacing a portion of the flour with potato starch. I’ll share my recipe next time.