YOU WOULDN’T THINK that the phrase “resistant starch” would be a hot topic on social media, but it’s 2024 and here we are. TikTokkers are freezing bread, chilling pasta, reheating rice, cooling potatoes, and singing the praises of “the resistant starch method” all for the sake of better regulating blood sugar.
And supplement makers are in on the excitement, too, selling resistant starch products that advertise a wide range of supposed benefits: supporting metabolism and digestion, reducing inflammation, and boosting your energy and mood.
But you have to wonder, is any of this true?
We turned to the research and talked to actual experts to find out.
What is Resistant Starch?
TO START, RESISTANT starch comes from a good family.
“Resistant starch is dietary fiber and dietary fiber has broad health benefits, including gut health, weight maintenance, glucose control, and protection against cancer,” says Joanne Slavin, Ph.D., R.D.N., professor of food science and nutrition at the University of Minnesota. Maybe you’ve heard of soluble fiber, which forms a gel in your gut to help you stay full, and insoluble fiber, the kind that helps you poop. Resistant starch is a third type that does a little of both.
Unlike simpler starches, your digestive enzymes cannot penetrate resistant starches, so the starches do indeed make it to your large intestine, where good bacteria in your gut feast upon them. An array of research suggests that consuming resistant starch can shift your gut bacteria profile in favor of beneficial species. These good bacteria produce helpful short-chain fatty acids with anti-inflammatory properties.
Should You Take a Resistant Starch Supplement?
FIRST, YOU SHOULD try to eat your resistant starch from food. (More on that later.)
Companies claim resistant starch supplements—which contain concentrated or chemically modified versions of indigestible starches from foods like rice and potatoes—can help you maintain healthy blood sugar, support digestion and gut health, boost your mood, and energy levels, and more.
While small studies suggest some potential benefits to supplementing with resistant starch, keep in mind that not all resistant starches are the same. There are five subtypes, and every supplement contains a different type (or blend). That means that the results of one study on resistant starch don’t necessarily apply to every product on the market.
Some possible (but not proven) benefits of supplementation include:
High Blood Sugar Control
A study review published in Frontiers in Nutrition showed that resistant starch types 1 and 2 (1 is found in whole foods, 2 in some supplements like corn-based resistant starch supplements) can help to reduce blood sugar after meals in people with type 2 diabetes or prediabetes. Resistant starch type 2 can improve fasting blood sugar and insulin function, possibly because it can be taken in larger quantities as a supplement than the natural food forms.
Weight Loss
In a small study published in Nature Metabolism, people who consumed a corn-based resistant starch supplement every day for eight weeks lost an average of six pounds and improved their insulin function, a key component of metabolic health. Study participants who took the supplement increased their concentrations of the helpful gut bacteria Bifidobacterium adolescentis and showed an increase of metabolites linked to burning fat.
GI Comfort
A small study in the Journal of Functional Foods showed that people who supplemented with a resistant starch from potatoes for four weeks reduced histamine levels in their gut, a known trigger of gastrointestinal disturbances. One catch: the supplement maker was involved in the study. (Whomp whomp.)
So as with anything trending on TikTok, some of the promises about resistant starch are overblown. While resistant starch might aid blood sugar control, there’s no evidence that it cures diabetes or does that famous thing so many supplements supposedly do, detoxify. (Your liver does that, by the way.)
Resistant Starch Foods
YOU DON’T HAVE to reheat all your carbs to consume resistant starch. You can find the stuff in:
- just-ripe bananas
- overnight oats
- beans
- nuts
- seeds
- peas
Then, consider a supplement as an insurance policy to get enough roughage—Americans only eat half the recommended amount of dietary fiber, says Slavin. “As a dietitian I always promote foods over supplements, but resistant starch supplements can also fit into some diets as a source of dietary fiber and a method to reduce calories,” says Slavin.
Studies have shown that people safely tolerate up to 45 grams per day with minimal side effects. “We don’t have a UL (upper limit) for fiber or resistant starch in the U.S.,” says Slavin, “so it is unlikely that you could over-supplement.”
Because resistant starch is digested more slowly than other fiber supplements (like the psyllium husk in famously regulating supplements like Metamucil), it is less likely to cause bloating and gas.
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