What is resistant starch and what can it do for me?
Understanding resistant starch is not hard once you compare it to what you already know about starches. We know that the starch that we eat is digested at different rates. The starch in potatoes, cereals, and baked goods digests very rapidly, but other starchy foods, like beans, barley, or long grained brown rice, are digested more slowly and cause a much slower and lower blood sugar rise.
Resistant starch actually goes all the way through the small intestine without being digested at all. In this way, it is more like fiber, and in some cases is classified and labeled as fiber.
So what makes some starch resistant?
There are four types of resistant starch:
- Starch that is difficult for the digestive process to reach, often due to a fibrous "shell". Grains and legumes which are cooked intact are an example. Also, some altered starches, such as Hi-Maize corn starch, are in both this category and the next.
- Some foods, such as unripe bananas, raw potatoes, and plantains, have a type of starch which our digestive enzymes can't break down.
- Small amounts of resistant starch (about 5% of the total) are produced when some starchy cooked foods, such as potatoes and rice, are allowed to cool before eating.
- Manufactured resistant starch, made by various chemical processes. It is not known whether these starches have the same benefits as those in the other three groups.
Most starchy foods have at least a small amount of resistant starch in them.
What are the benefits of resistant starch?
It seems that the more it is studied, the more positive effects are being found. Here are some of the benefits of resistant starch:
- Resistant starch is especially associted with one type of SCFA, called butyrate, which is protective of colon cells and associated with less genetic damage (which can lead to cancer).
- As with other fermentable fiber, resistant starch is associated with more mineral absorption, especially calcium and magnesium.
- Perhaps most exciting for people with sugar issues, resistant starch seems to improve insulin sensitivity. In the so-called "second meal effect", fermentable fiber and resistant starch are associated with improvedglucose tolerance the next day.
- Resistant starch produces more satiety.
- Resistant starch consumption is associated with lower cholesterol and triglyceride levels.
- Promotes "good" bacteria, and supresses "bad" bacteria and their toxic products.
- Promotes bowel regularity.
- Resistant starch in a meal is associated with less fat storage after that meal.
Brighenti, Furio et al. "Colonic fermentation of indigestible carbohydrates contributes to the second-meal effect." American Journal of Clinical Nutrition 83.4 (2006): 817-822.
Cummings, JH. "The Large Intestine in Nutrition and Disease: (monograph), December 1996, ISBN 2-930151-02-1
Englyst, Klaus and Englyst, Hans. "Carbohydrate Bioavailability." British Journal of Nutrition94 (2005): 1-11.
Englyst, Klaus, et al. "Glycaemic index of cereal products explained by their content of rapidly and slowly available glucose." British Journal of Nutrition. 89 (2003):329-339
Higgins, Janine. "Resistant Starch: Metabolic Effects and Potential Health Benefits." Journal of AOAC International 87 (2004):761-8.
Higgins, Janine, et al. "Resistant starch consumption promotes lipid oxidation." Nutrition and Metabolism 1.8 (2004): 1743-7075.
Robertson, M.D. et al. "Prior Short-Term Consumption of Resistant Starch Enhances Postprandial Insulin Sensitivity in Healthy Subjects." Diabetologia 46 (2003): 659-665.