Resistant starch (RS) has qualities that are somewhat unique. As it’s being touted today, RS will help reduce the glycemic response to some carbohydrate-based foods. The issue is that when and how an RS containing food is prepared and consumed seems to be important. Let’s take a look.

Food Preparation Methods

The most natural forms of resistant starch to eat, regardless of preparation, are beans, seeds, nuts, and legumes. The food preparation doesn’t seem to impact the RS in any way, so these are the best ways to get RS.

Eating bananas and plantains when they’re green provides a high amount of RS. The more they’re allowed to ripen, the higher the sugar content and the less RS.

Raw potatoes also seem to have a high amount of RS. Because most people don’t eat raw potatoes, the type of preparation impacts RS levels. The longer the potatoes are cooked, the more the starch is changed into sugars or starches that don’t contain as much RS. In a review study of potatoes, the cooking method that contains the most RS was baked, followed by deep-fried, and finally boiled. The problem with deep-fried is the additional fat.

Does Cooling Increase RS?

We rarely hear about nutrients being increased by food prep, but RS may be the exception. A lot of the recent focus on RS surrounds the possibility of increasing RS by cooking and then cooling the foods before eating. The RS that degenerates during cooking is partially restored in cooling, particularly in rice and pasta.

However, in a study that examined the difference between rice that was eaten immediately, kept at room temperature and eaten eight hours later, and cooled for 24 hours and then eaten, the amount of fiber increased by 0.64 grams, 1.3 grams, and 1.65 grams per 100 grams serving. Stated slightly differently, in a half-cup portion, there was an increase of one gram of fiber per serving. While it’s true, it’s not meaningful in the real world and probably not worth the additional effort.

RS and Type 2 Diabetes

Another benefit of RS is to reduce the amount of sugar that enters the blood stream. In the rice study, the cooked and cooled rice was fed to 15 healthy volunteers. Their glycemic response was reduced. While I think that’s great, there’s no indication that this will happen in T2D. On top of that, think about the additional steps required to achieve that. I think there’s a better way.

The Bottom Line

Resistant starch is legit; it acts as a prebiotic and reduces the glycemic response, but I don’t think we need to go out of our way to get more of it. Increasing our intake of beans, seeds, legumes, and nuts will increase our RS the most without jumping through hoops. If you like green bananas, eat them. Cook your pasta al dente and that maintains some of the RS in pasta. If you like to cook extra rice and pasta to use in later meals, now you know there’s a nutritional benefit. You don’t need to do anything else but eat the foods that naturally contain RS. Simply put, just eat better.

Next week is all your questions, so send them in if you haven’t already.

What are you prepared to do today?

        Dr. Chet

References:
1. Nutrients. 2018 Nov 14;10(11). pii: E1764. doi: 10.3390/nu10111764.
2. Asia Pac J Clin Nutr 2015;24(4):620-625.