Resistant starch is a type of starch that is “resistant” to digestion. This essentially means that the body cannot break it down like it can regular starch. Generally, starches are broken down in the small intestine and turned into sugar. Resistant starch, however, moves through the stomach and small intestine undigested and arrives at the colon intact. Once it reaches the colon, resistant starch behaves more like a prebiotic fiber than a usual starch. Prebiotics generally are fibers that the good gut bacteria in the colon consume. In other words, prebiotics feed probiotics. When these beneficial bacteria feed on prebiotic fiber and resistant starch, they produce short-chained fatty acids that are associated with many gut and general health benefits. One of the main short-chain fatty acids produced by these good gut bacteria is butyrate (butyric acid). Butyrate has been found to directly nourish the colonocytes (cells that line the colon).
Feeding the good gut bacteria and the cells of the intestinal lining is associated with many health benefits:
Improves the integrity and function of the gut: There is evidence that long-term intake of resistant starch induces pronounced changes in the colonic environment. It has been shown to reduce damage to colonocytes, improve mucosal integrity and reduce colonic and systemic immune reactivity. This reduction in immune reactivity could pose to benefit a slew of inflammatory conditions. Additionally, a 2013 study found that mice fed resistant starch showed a decrease in the number and size of lesions tied to colon cancer. They also showed an increase in an anti-inflammatory protein called IL-10.
Improves insulin sensitivity: Resistant starch has also been shown to improve insulin sensitivity in those with obesity and metabolic syndrome. Improved insulin sensitivity helps to protect against the development of and treat conditions like type 2 diabetes, metabolic syndrome, heart disease, and obesity.
Improves fasting blood sugar and lowers the blood glucose response to meals: Resistant starch seems to improve some hormone levels in the body that are associated with blood glucose regulation such as GLP-1. This is evident in some studies that have shown adding resistant starch improved fasting blood sugar as well as curbed the post meal blood sugar rise. Additionally, the post meal glucose effects may also extend to the subsequent meal consumed after the meal that contained the resistant starch, which is very exciting!
Potentially could helps with weight management: One study found that women who ate pancakes made with a resistant starch plus protein burned more fat after the meal than women who ate pancakes without resistant starch. Another study found that adding resistant starch to meals led to subjects reporting feeling fuller quicker, causing them to eat fewer calories.
Possibly can help lower cholesterol: According to a study in the Journal of Nutrition, rats fed resistant starch had lower total cholesterol and triglyceride levels than without the resistant starch. Another small study showed similar cholesterol lowering effects, including the lowering of LDL-C in men and women with metabolic syndrome.
It could help to remove “bad” bacteria:
Resistant starch has been found to be an effective treatment adjunct for cholera when added to the rehydration formula given to patients. The cholera bacteria seem to attach themselves to the resistant starch granules and then are evacuated in the feces.
Possibly could help improve deep sleep: A 2017 study found that rats fed prebiotics had better non-REM sleep (deep sleep) than rats who weren’t given prebiotics.
While there seem to be so many benefits of increasing resistant starch in our diets, there are also some potential concerns. Most of these concerns are attached to supplementing resistant starch versus obtaining it in natural foods. One of the main concerns is around supplementing with only one type of resistant starch (i.e. potato starch) that will feed only specific types of bacteria in our colon. Theoretically, that could create an imbalance of bacteria. We want a diversity of good bacteria without having too many of any one type. There are also murmurings that supplementing may contribute to SIBO (small intestinal bacterial overgrowth). In fact, some recommend that if you cannot tolerate even small additions of resistant starch to your diet, you may want to be evaluated for SIBO.
I would agree that if you choose to try resistant starch, it should be in limited amounts and of a variety of different types.
The four main types are:
Type 1: This type of resistant starch is in the coating of grains, seeds and legumes. It is bound within the fibrous cell walls of plants. Type 2: This type of resistant starch is in things like raw potatoes and green bananas. It is high in amylose content, which is indigestible in the raw state only. Cooking these foods causes changes in the starch making it digestible to us, and removing the resistant starch. Type 3: This type of resistant starch is present in foods like potatoes, legumes and white rice once they have been cooked and then cooled. Also called retrograde resistant starch since this type forms after Type 1 or Type 2 are cooked and then cooled. These cooked and cooled foods can then be reheated (preferably to less than 130-140 degrees) and still maintain the benefits of resistant starch. Heating at higher temperatures can again convert the starch back into a digestible form. Type 4: This type of resistant starch is man-made resistant starch. This type is usually seen on food labels of manufactured, processed foods. Examples you might see on a food label are “Hi-Maize,” polydextrin or modified food starch.
Most likely different resistant starch types have different effects on the gut flora, however the specifics on this has not yet been fully illuminated and will require more study.
So how do you start to add resistant starch to your diet?
Start with a half a tablespoon of raw potato starch, raw green banana or green plantain flour a day and slowly increase the dose as tolerated with a goal of about 2 tablespoons. For those on a low-carb or keto diet, the good news is resistant starch is keto-friendly since it bypasses digestion, and isn’t broken down like a typical carbohydrate. For example, one tablespoon of potato starch has about 10 grams of total carbohydrate, but 8 of these are in the form of resistant starch, so only 2 grams would be blood sugar impacting.
The key is to experiment and track how you feel after adding in resistant starch. Some people do just fine with it, while others become terribly bloated and gassy.
If you cannot seem to tolerate it, try reducing the dose and being very slow to increase. You may also try adding in a good probiotic supplement, especially if you have recently been ill or have had to take antibiotics. Lastly, if you cannot tolerate added resistant starch, you could try to get it in whole food forms like eating half of a green banana. Those who do not follow a low carbohydrate diet and are not carbohydrate sensitive, could also try cooking and cooling their rice or potato prior to eating it.
Do you take resistant starch? What has been your experience? Comment below!