Image: © Dea Zoffmann
When we hear of starchy foods, like bread, pasta, and baked potatoes, it is often associated with something negative, something to avoid or limit. But resistant starch is actually very good for us and something we should strive to include in our diet on a daily basis.
Most carbohydrate-rich foods contain starches. Starches are essentially long chains of glucose. In other words sugar. (This is why starches get such a bad rap).
Sugar, from carbohydrates, along with fats and proteins, is what fuels the body.
Starchy foods range from highly refined foods, like white bread, over whole grains and legumes, and on to vegetables and fruits like carrots, potatoes, and bananas.
Most of the starch you eat gets converted into sugar and as such serves as fuel for the body. But not all starches are created equal. Resistant starch is different, and it can radically alter your intestinal gut microbiome for the better, and in doing that have a positive impact on your health and general well being.
What is Resistant Starch and How Can It Benefit You?
Resistant starch is simply starch which is resistant to digestion – our digestive system cannot break it down.
Instead of being broken down like other carbs – and used to fuel the body’s immediate needs – resistant starch moves through the stomach and small intestines undigested and ends up in the large intestine/colon virtually intact. In this regard it resembles fiber.
But even though our body can’t get fuel from resistant starch, this form of starch is not all useless. On the contrary.
On its way through the large intestine your gut bacteria will feed on these resistant starches and ferment it. Through this fermentation process your gut bacteria produces something called Butyrate, or Butyric Acid (a short-chained fatty acid). Butyrate is an energy source for the cells which line your gastrointestinal tract. In this way resistant starch acts like a powerful prebiotic.
A prebiotic is what your good gut bacteria (probiotics) eat.
Without a steady input of good prebiotics your probiotics will not function optimally, which can lead to many kinds of health issues. From a sluggish immune system, to autoimmune diseases, and mental health issues, to name a few.
Along with strengthening our all important digestive health by feeding all that good intestinal bacteria, resistant starch has several other health benefits, including:
Resistant Starch Reduces Insulin Resistance
When you eat foods containing regular digestible starches, like for example a freshly baked potato, your body releases insulin in order to deal with the sudden spike in blood sugar. But because resistant starch passes through your system virtually undigested, this sudden spike in blood sugar doesn’t happen, and your body won’t have to release a lot of insulin in order to deal with it.
You can look at it like this: When you eat resistant starch, instead of sending your blood sugar on a roller-coaster ride – which is what happens when you eat a freshly baked potato – it goes instead on a perfectly manageable stroll up and over a gently rolling hill.
The more strolls over gently rolling hills your blood sugar goes on, the less insulin will be required to deal with sugar in your blood. So you will have less insulin circulating in your bloodstream at any given time. This makes your cells more sensitive to insulin.
On the flip side, the more roller-coaster rides you send your blood sugar on, the more insulin will be constantly circulating in your system, making your cells less sensitive to insulin over time.
High insulin sensitivity (aka low insulin resistance) is a good thing.
On the other hand, if you have high insulin resistance (aka low insulin sensitivity) due to chronically elevated blood sugar, your risk of developing serious conditions, like type-2 diabetes, metabolic syndrome, and heart disease, is greatly increased.
Resistant Starch Helps with Weight Management.
As is also the case with fiber, including resistant starch in a meal makes you feel fuller longer, thereby reducing the number of calories you consume in a day.
But not only that: The ability of resistant starch to change the gut microbiome (by serving as a prebiotic to our good gut bacteria) has been shown to influence energy absorption – how your body deals with the foods you eat – and the development (or not) of obesity. It appears to actually have an impact on the body’s ability to burn fat.
Resistant Starch Keeps you Regular.
Resistant starch can also help you avoid and/or deal with constipation. This is because resistant starch moves through your system undigested much like insoluble dietary fiber does. And it is no secret that a high dietary fiber intake makes us bee-line for the bathroom at regular intervals.
Types of Resistant Starch
There are four types of resistant starch:
Type 1: Is found in grains, seeds, and legumes (beans and lentils) and resist digestion because it is embedded in the fibrous cell walls of these foods.
Type 2: Is found in some starchy foods, like raw potatoes and green (unripe) bananas.
Type 3: Is formed when certain starchy foods, like potatoes, rice, and pasta, are cooked and then cooled. The cooling turns some of the digestible starches into resistant starch.
Type 4: Is man-made and you might see on food labels of processed foods. It may show up as something like modified starch or polydextrose.
Different types of starch can exist within the same food.
Depending on how a food is prepared the amount of resistant starch may change.
If, for example, you allow a green banana to ripen the resistant starch will turn into regular, fully digestible starch.
On the flip side, as you saw in type three above, if you allow a cooked potato to go cold before you eat it, a good part of its otherwise digestible starch turns into resistant starch.
Good Sources of Resistant Starch
Cooked beans and lentils. They have a naturally high content of resistant starch. Depending on the type, you’ll get 1-5 grams of resistant starch per 3.5 ounces (100 grams) serving. Cooling them down before eating them will increase the amount of resistant starch even more.
Recipe: Spicy Red Lentils & Pumpkin Soup,
Recipe: Chickpea Salad with Preserved Tofu,
Recipe: White Bean & Potato Stew,
Recipe: Red Lentil Pasta Sauce
Oats. Both raw and cooked oats have a naturally high content of resistant starch. Leaving your oatmeal to cool down overnight will increase the amount even more. (See a pattern emerging here?)
Recipe: Oatmeal using Whole Oats
Recipe: Mango & Blueberry Cobbler
Cooked and cooled potatoes. Letting them cool down for several hours or overnight is the best strategy. Cooked and cooled potatoes will retain their resistant starch even if reheated. In fact the amount of resistant starch increases with reheating.
Recipe: Potato & Spinach Salad
Cooked and cooled rice. And as is the case with potatoes, reheating the rice doesn’t appear to destroy the resistant starch. On the contrary, studies have even shown an increase in resistant starch in rice that has been cooked, cooled, and then reheated. Brown rice (or red or black) is preferable to white rice due to its higher fiber content (not to mention overall superior nutrition profile).
Recipe: Rustic Fried Rice
Pasta made from Durum wheat. Durum wheat has a hard texture and is used for making semolina with coarse particles. It therefore contains a high amount of resistant starch and, consequently, the glycemic response you get after eating pasta made with semolina is substantially lower than after after eating pasta made from regular white flour. If you eat it cold in a pasta salad you will be even better off.
Recipe: Creamy Lemon Fettuccine with Hummus and Fresh Rucola
Barley. Like oats, this particular grain also has a naturally high content of resistant starch.
Raw potato starch. Contrary to the whole foods mentioned above you shouldn’t heat raw potato starch, as heating destroys this type of resistant starch. Instead it can be added to smoothies or other drinks.
As eluded to above, cooking, cooling, and then reheating starches only serves to increase their content of resistant starch. That is excellent news to me and puts the sometimes dreaded leftovers in a completely new and positive light.
Since it was discovered in 1982 resistant starch, and its potential benefit to our health, as been the subject of much research over the last couple of decades. And what this research is continuously making clear, is that resistant starch, through its interaction with our gut microbiome, does indeed have a significantly positive effect on our health.
So, making sure you get some form of resistant starch every day – and ideally with every meal – will pay dividends down the road and give you a much better chance of living an active and healthy life well into ripe old age.
Detailed medical articles to further stoke your curiosity:
Resistant Starch: Promise for Improving Human Health
The gut microbiome: Relationships with disease and opportunities for therapy
Effect of cooling of cooked white rice on resistant starch content and glycemic response
Evaluation of resistant starch content of cooked black beans, pinto beans, and chickpeas
Resistant starch analysis of commonly consumed potatoes: Content varies by cooking method and service temperature but not by variety
Can gut microbes play a role in mental disorders and their treatment?
The microbiome in autoimmune diseases
The Interplay between the Gut Microbiome and the Immune System in the Context of Infectious Diseases throughout Life and the Role of Nutrition in Optimizing Treatment Strategies
Resistant starch consumption promotes lipid oxidation