A New Form of Carb?
The word “carb” is thrown around a lot. However there are several different types of carbohydrates including sugars, starches, fiber and one you may have not heard of before: Digestion Resistant Starch.
Digestion Resistant Starch (resistant starch for short) is not fully digested and absorbed, but instead ferments in the large intestine and is turned into short-chain fatty acids (SCFA’s) by bacteria. So it is a prebiotic and feeds beneficial bacteria in the colon.
Where does Resistant Starch come from?
All starches come from two polysaccharides: amylose and amylopectin. A polysaccharide is just multiple units of sugar hooked together, and MOST of the time a starch is digested to glucose.
Amylopectin has a large surface area that allows it to be broken down quickly resulting in larger and quicker spikes of glucose (blood sugar) along with corresponding increases in insulin which is where the dark side of starch intake can show up.
Amylose has much less surface area so is much more resistant to digestion. Amylose is what makes resistant starch resistant! These starches produce much lower glucose and insulin spikes.
Resistant starch is similar to fiber, but nutrition labels rarely mention resistant starch content.
Digestive Tract Benefits of Resistant Starch
As mentioned above when resistant starch is fermented by bacteria in the large intestine short chain fatty acids (SCFA) such as acetate, butyrate, and propionate, along with gases are produced. SCFAs can be absorbed into the body from the colon or stay put and be used by bacteria for energy.
Evidence suggests that SCFAs may benefit us in many ways. For instance, they:
- Stimulate blood flow to large intestine (colon)
- Increase nutrient absorption
- Inhibit the growth of pathogenic bacteria
- Reduce absorption of toxins
Other Benefits of Resistant Starch
Lower Calorie Intake – we only absorb 2 calories per gram of resistance starch (versus about 4 calories per gram from other starches). This is a really big deal because although you take in less calories from resistant starch it is VERY effective at satisfying hunger and produces high satiety levels!
Reduced Hunger – the SCFA’s produced from resistant starch cause the release of hormones that reduce hunger! This takes time so the longer that you consistently eat resistant starch the more the body adapts to produce more SCFA and the more pronounced the hunger lowering benefits become.
Improved Lipid Levels and Fat Metabolism
Resistant starch can help lower blood cholesterol and fats. It has also been shown to reduce the production of new fat cells. The SCFAs produced from resistant starch also reduce the release of carbohydrates by the liver thereby increasing the amount of fat we burn.
Improved Insulin Sensitivity
The reduced insulin response to resistant starch is very significant. Constant high levels of insulin in response to high levels of sugar and other non-fiber carbohydrate intake reduces the cells insulin sensitivity and overtime this can result in Type 2 Diabetes! This has big ramifications for the treatment of this form of diabetes which is sky-rocketing.
The effect on glucose and insulin metabolism is very impressive. Some studies have found a 33-50% improvement in insulin sensitivity after 4 weeks of consuming 15-30 grams per day.
Decreased Digestive Issues
Resistant starch may help prevent and reduce existing irritable bowel syndrome, diverticulitis, constipation, and ulcerative colitis.
Immune System Enhancement
Resistant starch can help balance immune response in the gut by balancing the production of immune cells and inflammatory chemicals.
Sources of Resistant Starch
Resistant starch is found in starchy foods such as:
Beans and Legumes
Starch Fruit and Vegetables
Getting More Resistant Starch
There are three ways to get more resistant starch: either get them from foods, supplement them or do a little of both.
Some common popular food items that are easy to find include raw potatoes, cooked and then cooled potatoes or rice, green bananas, cashews and raw oats.
If you are eating a low carb diet and want to make sure you keep your sugar and digestible starch intake very low focus on raw potatoes or green bananas which both have almost no digestible carb. Also remember that by cooking and then cooling (24 hours in the fridge) potato and rice you can boost resistant starch content by about 60%!
Or you can use raw potato starch powder (Bob’s Red Mill Raw Potato Starch) which is easy to sprinkle into foods and shakes. This supplement has very little taste. Benefits will likely max out at 32 grams of resistant starch per day and start slowly and gradually increase to let your digestive system adjust.
It will take 2 – 4 weeks for the production of short chain fatty acids to increase and to notice all the benefits!