You may have heard of resistant starch, or RS. Some of you may already know all about it and have been incorporating it into your diet for a long time. But if not, take a look at RS and its many benefits.
Fiber and starch are often confused, but they are not the same thing. Fiber is indigestible, and starches are long chains of glucose and usually highly digestible — which is why it causes those nasty spikes in blood sugar. Resistant starch is a different animal altogether. Although it is a starch, it passes through the digestive tract undigested; hence its name, resistant starch.
RS has been called the “third fiber”, with the first two kinds being insoluble and soluble. But unlike the first two, familiar types of fiber, much of the RS is also fermented once it reaches the large intestine.
At first glance, having something fermenting in your large intestine may not seem like a good thing — bring on the air freshener and fan! And it’s true, eating too much RS too soon may well cause not only gas but bloating and other unpleasant side effects. But that’s true with almost anything.
Take veggies, for example. Everyone should eat mega servings of veg every day, right? Well yes, but when a person who eats little to no veg decides to start eating five servings a day and does it all at once, there are probably going to be side effects. But this doesn’t mean that a large variety and amount of veggies each day is a bad thing, or that God forbid, veggies are bad!
How Resistant Starch Works
Once RS has made the long trip from your stomach through your small intestine and into your large intestine (undigested), it begins to ferment. Why is this good? It’s good because your friendly, healthy bacteria love it, and will happily chomp away on the RS, becoming even healthier and I daresay, friendlier in the process. Hey, they need to eat, too. Feeding your microbes RS every day makes them happy, and lots of happy gut bacteria equals a healthy gut. Which in turn equals a healthy you.
This is what a prebiotic is – good food for your good bacteria. Probiotics are wonderful and necessary, and everyone should take them in one form or another, but putting helpful bacteria into your gut will do you no good if they then starve. They’re hungry. Feed them.
But that’s not the end of the story. Once the microbes have dined on their fave food, they produce butyrate (BTA), a short chain fatty acid (SCFA) that is a body’s superhero. Some of butyrate’s documented benefits:
- Reduces the colon’s ph level
- Reduces inflammation
- Help prevent colon cancer
- Tumor-suppressive and causes programmed cell death in colon cancer cells
- Weapon against Crohn’s, IBS, and other inflammatory bowel diseases
- Aids in weight loss – RS has fewer calories than other starch and promotes satiety, so you eat less.
- Fights insulin resistance/metabolic syndrome/diabetes (also helpful for weight loss)
- Preliminary studies show it increases mineral absorption
As if this weren’t enough, here’s more happy news: butyrate is also the favorite fuel of the cells that you’re your large intestine. So, by consuming RS, you are directly feeding your good-guy gut microbes, while indirectly fueling and nourishing the cells lining your large intestine. This is one reason why RS is so helpful in treating bowel diseases, or helping to prevent them in the first place.
But Starch is High in Carbs!
Yes…and no, in a sense, at least when it comes to RS. If you eat a plate of steaming hot white rice, you’ve just ingested a lot of blood-sugar-spiking, fattening carbs. But if you let the rice cool in the fridge overnight and then heat it again, you have yourself a plate of resistant starch. Even better, the amount of RS would go higher still if you were to heat it a third time, then let it cool to room temperature before eating it.
The same thing happens with other foods that we would normally eat hot, like legumes and potatoes (all varieties, including sweet potatoes), and even barley and other cereal grains. That’s because when cooled, they lose their original molecular structure and a new structure is formed, in a process called retrogradation. Studies have found that re-heating and re-cooling them increases retrogradation even more, giving you and your helpful intestinal bugs a higher amount of RS. Remember – happy bugs, happy gut. Happy gut, happy you.
Ah, I can hear the chorus now: But I don’t want to eat cold rice! Or cold potatoes, pasta, or beans! Believe me, I felt the same way. But dry your tears. There is a silver lining in this gloomy little cloud.
You don’t necessarily have to eat these things ice-cold, straight from the fridge. Perhaps the RS would be at its absolute highest then, but eating them at room temperature works, too. I realize that even this can be difficult at first if you’re a person who, like me, has always insisted that foods that are normally eaten hot be hot, not warm when you eat them, and that the cold ones be very cold, not just cool. I must have been like this all of my life, because when I was five, my then-13-year-old sister noted in a scrapbook/school essay she wrote about me that I was quite picky about food, wanting my hot foods hot and my cold foods cold.
But really, we can get used to pretty much anything if we want to. When I first wrestled with the idea of eating my beloved hot potatoes at room temperature, I made an executive decision and firmly announced to myself: Either you eat them at room temperature or you don’t eat them at all. Which will it be?
You’ve probably guessed I chose the cooled potatoes. I adore potatoes and would rather them ice-cold than not at all! And it didn’t take long to get used to eating my RS-containing foods like this. Now, I sometimes do eat mashed potatoes straight from the fridge. Or you could do like my sisters and eat them raw (none for me, thanks).
And for you holdouts who categorically refuse to eat your hot foods at room temp, there is yet hope for you as well, in the form of yummy things like potato salad, bean salads, pasta salads and the like. Many people add potato starch to their smoothies (although you may want to go easy on the amount. I tried that once, and my smoothie had to be eaten with a spoon.) There are probably other delicious ways you can think of to get your ramped-up versions of RS; just use your noodle.
Sorry. I simply couldn’t resist.
Okay. Back to the serious stuff. At the end of this post are a few recommendations for books that will tell you how to do just that, in addition to a more comprehensive look at RS and its benefits
Types of Resistant Starch
There are four types of RS. Let’s take a quick look:
- RS1 is the resistant starch in whole grains, seeds, and legumes. It has a hard coating that protects it from breaking down, so it can pass through your digestive system without being absorbed.
- RS2 is a crystalline starch with a tightly-packed structure, so digestive enzymes can’t break it down. Examples of RS2 are foods like green bananas and plantains, and those raw potatoes my sisters love.
- RS3 is the retrograded starch we discussed earlier, that comes from heating and cooling.
- RS4 is a special cornstarch that is much higher in RS than conventional cornstarch and other many other RS foods. It has been vilified as a starch created in a lab by the likes of Dr. Frankenstein and Mr. Hyde, to be avoided like the bubonic plague. And for brands that use genetically modified (GM) corn, I would agree. However, there is a brand out there called Hi-Maize 260, which claims to have achieved high RS status through selective breeding, not GM. In that case, I don’t see anything wrong with it, but as always, use your own judgment.
In reading over RS1-3, you may have wondered if a food can have more than one type of starch. Yes, it can – the different starches have learned to peacefully coexist.
Speaking of the various forms of RS, I almost forgot to mention that not only is potato starch (potato starch, not flour — yes, there is a huge difference) resistant, but cornstarch, and tapioca starches are resistant starches, too. These are a handy way of increasing your RS by using them to thicken gravy, soups, sauces, and even home-made yogurt. In addition to these starches, there is also a lovely gluten-free grain/flour out there that is extremely high in RS and is a nutritional powerhouse — teff.
For those who prefer to investigate a bit further before taking the RS leap or simply possess curious minds (or both), here are a few books you should find to be helpful.
- The Resistant Starch Bible by Chase Williams: The first book on RS I read, and very helpful
- The Potato Hack by Tim Steele: Easiest diet ever – simply eat nothing but potatoes for 3-4 days. But this book contains a wealth of information besides this mind-boggling instruction, like the science behind the potato hack (Tim is a science geek with a Masters in biotechnology) plus variations, recipes, and what to do if it doesn’t seem to be working. There’s also a comprehensive review of RS, gut health, the history of the potato, and a growing guide if you want to grow your own.
- The Starch Revolution: Resistant Starch Cookbook by Bethany Silver: For those who want nothing to do with a potato fast, this cookbook shows how to incorporate a variety of RS foods into your diet.
Proceed With Caution
As I mentioned earlier, it’s always best to start introducing new diets, supplements, exercise routines etc., slowly and cautiously. Don’t just dump a boatload of starch into your next smoothie — not only because you probably don’t want to have to eat it with a spoon (or maybe you do), but because too much, too fast may be distinctly unpleasant for your digestive system. Start with a little at a time and slowly increase. A little gas is no big deal, especially if you’re alone! But gas pains, cramping, diarrhea…naw. You don’t want that.
I also wanted to mention something about potato starch. There are claims floating around that some people with diabetes saw their blood sugar levels go up slightly after having used potato starch for a few weeks, except when they also took psyllium. I don’t know how valid these claims are, so take that with a grain of salt. Or a big spoonful of psyllium.
Also, there are arguments over whether or not people who have gut issues like IBS, Crohn’s, ulcerative colitis, etc. should be using RS. Many people with these conditions swear that RS has helped them tremendously, and studies seem to bear this out. Others claim that ingesting RS only makes it worse. I suspect that the answer lies somewhere in between, as usual. It could be that the folks that claim it makes bowel diseases worse may well be the ones who tried taking too much in too short a time and suffered the consequences.
I have gut issues and since I’ve introduced RS, I’ve had no problems with it.
Another theory is that RS might not be good for people with SIBO, and that they need to address that issue before introducing RS into their diets. That may be. If you have SIBO, do your homework and read up on the debate and the studies. You should do this even if you don’t have SIBO. Be informed!
The holidays are upon us. If you start slowly and are able to handle RS, you really can have your potatoes (or pasta, or grains) and eat them, too!