The Majority of the carbohydrates that we consume in our diets are starches. It is found in foods like grains and potatoes. Starches are composed of long chains of glucose that provide us with sustainable energy throughout the day. There are instances where starch passes through the digestive system and it isn’t broken down. Instead it is turned into short chain fatty acids by intestinal bacteria. Many studies have shown how resistant starch can benefit our health, but what exactly is resistant starch?1
There are four different types of resistant starch.
They are grouped based on structure or source. Type 1 is found in grains, seeds, and legumes. This type is inaccessible to digestive enzymes because it’s bound within fibrous cell walls. Type 2 is found in starchy foods, like raw potatoes and green bananas and high amylose starches. Type 3 is formed when starchy foods are cooked and then cooled. The cooling process turns digestible starches into resistant starches though a process called retrogradation. Type 4 is man made through a chemical process. It sounds simpler than it is. Several types of resistant starch can be present in the same food. The preparation method of the food is the determining factor for how much resistant starch is available in the food. 2
How does it work?
Most starches are broken down into sugar by enzymes in our small intestine and then absorbed into the blood, but as we know we have difficulty absorbing resistant starches. Instead that resistant starch passes through the small intestine and is fermented by intestinal bacteria in the large intestine. During fermentation short chain fatty acids (SCFA) like acetate and butyrate are produced. SCFA are absorbed or remain in the colon to be used by bacteria for energy. SCFAs are shown to stimulate blood flow in the colon, increase nutrient circulation, inhibit the growth of pathogenic bacteria, aid in the absorption of minerals, and helps to prevent the absorption of carcinogenic compounds. How much SCFAs present in our colon is dependent on the type of carbohydrate consumed. The more resistant starch consumed the greater the amount of SCFAs.3
What is it good for?
There are many potential benefits of resistant starch including improved blood fats, better satiety, better insulin sensitivity, improved digestion, better body composition, and improved immunity. Resistant starch may aid in lowering blood cholesterol and fats, while simultaneously decreasing the production of new fat cells. Also, resistant starch can increase the amount of fat we use for energy because SCFAs can prevent the breakdown of carbohydrates in the liver. Resistant starch is also known to improve satiety. It can help us feel full because SCFAs can trigger the release of hormones such as leptin that decrease the desire to eat. This takes some time for your body to adapt. It may take up to a year, but the resistant starch will slow the amount of nutrients released into the bloodstream, which keeps one’s appetite stable. Resistant starch is also known to improve insulin sensitivity. Since resistant starch doesn’t digest into blood sugar our bodies do not release as much insulin in response. Another benefit of resistant starch includes improved digestion. Resistant starch acts similar to soluble fiber. It adds bulk and water to the stool and aids in regular bowl movements. SFCAs also help prevent the development of abnormal bacterial cells in the colon and increase mineral absorption. These factors may help alleviate irritable bowel syndrome, constipation, and ulcerative colitis. Furthermore, resistant starch may aid in weight control.3 Since resistant starch contains fewer calories per gram than other starches, it can help us eat less. We only extract 2 calories per gram of energy versus 4 calories per gram from other starches. This means that 100 grams of resistant starch is only worth 200 calories while other starches provide 400 calories per 100 grams. Foods high in resistant starch will fill you up, without filling you out.4 Lastly, consuming resistant starch may positively influence the production of immune cells and inflammatory compounds in the gut thus, thus improving immunity.3
How to include resistant starches in your diet.
The two ways to add resistant starches to your diet are either through the food you eat or through supplementation. There are many foods you may already be eating that contain resistant starch including cooked then cooled potatoes, various legumes, cashews, and raw oats. These are all high-carb foods which may not be optimal for people following a low-carb diet. With that being said, you can still include resistant starch in your diet without adding any digestible carbohydrates. This can be done by purchasing raw potato starch. Raw potato starch contains about 8 grams of resistant starch per tablespoon and negligible amounts of usable carbohydrates. It tastes rather bland, but can be used by mixing it with water, putting it in smoothies, or sprinkling it on food. It is important to start slowly and work your way up, because consuming too much suddenly may lead to discomfort and flatulence. It may take about a month before you begin to notice all the benefits resistant starch has to offer.
- Wiley. Foods rich in resistant starch may benefit health. Science Daily. https://www.sciencedaily.com/releases/2017/01/170105082819.htm. Accessed January 12, 2017
- Lockyer S, Nugent AP. Health effects of resistant starch. Nutrition Bulletin. January 2017. doi:10.1111/nbu.12244.
- Andrews R. Resistant starch: What is it? And why is it so good for you? Precisionnutrition. http://www.precisionnutrition.com/all-about-resistant-starch. Accessed January 12, 2017.
- Weisenberger J. Resistant starch — this type of fiber can improve weight control and insulin sensitivity. Today’s Dietician. http://www.todaysdietitian.com/newarchives/090112p22.shtml. Accessed January 12, 2017. .