Most of the carbohydrates we consume are made up of starch; long chains of glucose commonly found in grains, potatoes and various foods. Traditionally starches are broken down by enzymes in the small intestine into simple sugars. Starch is a source of energy for the body.
But not all of the starch is digestible. Parts of the starch are resistant to digestion and pass through the digestive tract unchanged, which are known as resistant starch, with a similar function to soluble fiber.
Resistant starch is very popular in nutritional research, with studies showing many powerful health benefits for the human body including lower blood sugar levels, improved insulin sensitivity and a reduced appetite. Other health benefits include improving the blood lipids profile, increased absorption of micronutrients and an improved bowel health, although this research is still fairly new and ongoing.
What Is Resistant Starch?
In the past, we’ve been constantly told that potatoes and pasta do little more than increase our waist size and are empty calories. But potatoes, corn, rice and other foods previously thought of as ‘bad’ carbs may actually help you lose weight. Resistant starch is considered a unique type of fiber that can have a powerful impact on weight loss and your overall health.
Although you may not of been aware of resistant starch before, it’s something you’ve probably been eating all your life. Resistant starch occurs naturally in many carbohydrate-rich foods like potatoes, grains and beans, especially when these foods are cooled down. As the name suggests it resists digestion like many types of fiber but can also increase your body’s fat burning abilities, fill you up and reduce your appetite. It’s like a gift from above for many dieters.
The research on resistant starch doesn’t stop at weight loss, it’s also been considered a nutrient which combats major diseases including the prevention of cancer, fighting diabetes and heart disease and boosting your overall immune system. Unfortunately this doesn’t mean eating more French fries is going to help us get super healthy and skinny. Let’s look at how resistant starch works and how we can get more of this “superfood” into our diets.
How Does Resistant Starch Work? (The Science Bit!)
Starch is a polysaccharide consisting of two saccharides, or sugars; amylose and amylopectin Amylopectin has a larger surface area which is broken down quicker and causes a rise in blood sugar and therefore a large rise in the insulin produced by the body. Amylose, dominant in resistant starch is a straight chain with a smaller surface area for digestion. Amylose is digested much slower and is less likely to result in glucose or insulin spikes.
Instead of being broken down by enzymes in the small intestine, resistant starch molecules make their way to the colon (or large intestine) where bacteria ferment it and break it down to short chain fatty acids. Fatty acids like acetate, butyrate and propionate are produced and can be absorbed back into the body by the colon or stay in the colon and be used for energy. These short chain fatty acids can also help protect or repair the inner lining of the intestine wall and are thought to be good for your overall health by stopping the development of abnormal cells in the gut.
Not all types of resistant starch are the same and four varieties have been recognised.
Is usually found in grains, seeds and legumes. It avoids digestion because it’s encased within fibrous cell walls of the kernel.
Is found in starchy foods when raw or unprocessed including green bananas and raw potatoes.
Is created when some starchy foods like potatoes or rice are cooled down after cooking. Cooling the food can turn some of the digestible starch into resistant starch by a process called retrogradation.
Resistant starches are starches that are chemically modified to resist digestion. Processed foods like bread and crackers often include man-made resistant starches.
Sometimes several different types of resistant starches can coexist in the same food. The preparation method will have a major impact on the total amount of resistant starch in foods; with bananas, for example, that are allowed to ripen or go yellow degrade the resistant starches and turn them back to normal digestible starch.
How Resistant Starch Can Benefit Your Health?
The obvious connection between resistant starch and your well-being is in the gut health benefits it offers. Butyrate, one of the short chain fatty acids produced when resistant starch is fermented in the colon, is the preferred fuel source of cells that line the colon. Resistant starch feeds both the friendly bacteria in the gut and indirectly feeds cells in the colon by increasing the levels of butyrate. Resistant starch also reduces the pH level, can help prevent inflammation and results in several changes that can lower the risk of colorectal cancer, the fourth most common cause of cancer death in the world.
Resistant starch can have many benefits for your metabolic health too. It can improve insulin sensitivity and lower blood sugar levels which can help you avoid chronic diseases and live longer. Having low insulin sensitivity is one of the highest causes of many of the world’s most serious diseases including metabolic syndrome, diabetes type 2, obesity, cardiovascular disease and Alzheimer’s disease. Some studies have found just consuming 15 to 30 grams per day of resistant starch can improve insulin sensitivity by 33 to 50 percent after just four weeks. Resistant starch can also have what’s called a second meal effect where eating resistant starch for breakfast can help prevent blood glucose spikes after lunch or your next meal.
Perhaps one of the biggest benefits of resistant starch is the boost to your immune system. Lower levels of healthy bacteria in your digestive system can make it difficult for the body to fight off disease. Resistant starch boosts the growth of probiotics, the same type of bacteria cultures found in yogurt that help balance your good versus bad bacteria ratio in the gut.
Resistant Starch as the Dieter’s New Best Friend
Your body’s calorie burning can be increased by adding more resistant starch to your diet. Butyrate, one of the beneficial fatty acids produced by the fermentation of resistant starch can block the body’s ability to burn carbohydrates. By stopping the liver from using carbs for energy, instead stored body fat and more recently consumed fats are burned for fuel. Butyrate effectively puts a block on your body’s fuel line and forces cells to use fat rather than carbs for fuel.
A study that looked at the effect of resistant starch on lipid oxidation found that replacing just 5.4 percent of your carb intake with resistant starch can increase fat burning by 20 to 30 percent after a meal.
Like other types of fiber, resistant starch can keep you feeling fuller longer and suppress those feelings of hunger. Short chain fatty acids trigger hormones like leptin that reduce your body’s need to eat. Adding resistant starch to a meal increases that fullness feeling and you’ll eat fewer calories too. As a bonus, resistant starch has only 2 calories per gram compared to the 4 calories per gram of regular starch.
How to Increase Resistant Starch in Your Diet
Although there are no FDA guidelines on just how much resistant starch you should consume daily, a national survey shows the average American adult is only eating 5 grams per day, much less than the minimum 6 grams per meal recommended for health benefits. There’s no point in over consuming excess resistant starch as anything over 50 or 60 grams per day is likely to pass straight through your system. Consuming too much may overwhelm the fermentation in your colon and cause diarrhea and bloating.
There are two ways of getting more resistant starch into your diet; either from foods or with supplements. Many common foods are high in resistant starch including raw potatoes, cooked and then cooled down potatoes, green bananas, a variety of legumes, cashew nuts and raw oats. The way you prepare your starch-containing foods can have the largest impact on just how much resistant starch you get. Cooking or heating foods destroys most resistant starches but allowing them to cool can recapture some of the resistant starch in certain foods.
Many of these foods you may have noticed are high in carbohydrates, which is no good if you’re on low-carb diet. Fortified foods can be another way of introducing more resistant starch into your diet. Many commercial foods are bulked out with Hi-maize, a branded resistant starch powder made from corn. It can be used in baking with fewer calories and can replace a quarter of the flour normally used in a recipe without affecting the texture or taste. Looking for products that include resistant starch featured on their packaging or in the name is an ideal way to supplement your intake.
Best Foods to Add Resistant Starch to Your Daily Life
Start the day with a bowl of oats for that all-important second meal effect, we discussed earlier. A 100-gram bowl of cooked oatmeal flakes can contain about 3.6 grams of resistant starch and is also high in antioxidants. By leaving the cooked oats to cool for several hours or overnight you could actually increase the resistant starch even more.
Rice is another low cost and easy way to add more resistant starch to your diet. By cooking the rice at the beginning of the week and keeping it chilled, the cooling down can increase the resistant starch present. Brown rice is preferable as it contains more fiber and provides more micronutrients like manganese and magnesium.
Raw Potato Starch
This white powder that looks like normal flour is one of the most concentrated sources of resistant starch with approximately 72 percent of the starches present being resistant. Due to the high levels of resistant starch you only need 1 or 2 sometimes simply added to a yogurt or smoothie.
Cooked and Cooled Potatoes
This is the one we have all been waiting for, a way to eat potatoes and still lose weight. It’s best to cook the potatoes in bulk, then allowing them to cool down for several hours. When they are fully cooled, cooked potatoes can include high amounts of resistant starch in addition to essential vitamins like potassium and vitamin C. The following Youtube video shows a cold potato salad which can be an excellent way of getting your daily fix of resistant starch.
Can Resistant Starch Work for You?
If your weight loss diet seems to have taken you as far as it can, you’re having problems with high blood sugars or just general digestive problems it may be worth trying to add some resistant starch to your diet. Don’t expect instant results as it often takes the gut a couple of weeks to adjust to the increased production of short chain fatty acids before you’ll see any results. But unlike most diet plans you won’t have to cut too many of your favorite foods from your diet, just reintroduce a few.