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.
