What is digestion resistant starch?
I am a very fortunate physician. Often my patients will present me with something new in health and healing.
Two weeks ago, a patient introduced me to the concept of digestion resistant starch (DRS). DRS is starch in a specific molecular structure that resists digestion in the stomach and small intestine. It is not digested until it reaches the large intestine.
There it feeds a number of “good” bacteria that we now know are important to long-term health.
Starch is composed of sugars like glucose connected together to form long molecules called polysaccharides.
Starch is produced by most plants as a primary form of energy storage. Since we eat plants, starch is the most common source of carbohydrate in our diets. It is found in large amounts in potatoes, rice, corn, wheat and oats.
However, all starch does not have the same molecular structure and is not digested the same way.
Starch can be classified into three basic categories, rapidly digestible, slowly digestible and digestion resistant.
Rapidly digestible starch is changed into sugar in as little as 20 minutes in the mouth, stomach and upper small intestine.
Slowly digestible starch takes longer to change into sugar (about 60 minutes) and this happens in the small intestine.
DRS is able to make it to the large intestine where it is, to a great extent, used as a food source by bacteria and fermented.
The medical research on DRS is, at this time, limited although the claims on the internet are quite extensive.
Medical research on foods that contain DRS have demonstrated benefits in diabetes, heart disease prevention, irritable bowel, arthritis, autoimmune illnesses and maybe even in reducing the risk of dementia.
A recent study in the medical journal “Cellular Physiology and Biochemistry” demonstrated that the composition of the bacteria in the large bowel changed significantly with the introduction of DRS in the diet. There was an increase in those bacteria that produce compounds that we use to stay healthy and a reduction in bacteria considered to be pathogenic.
Foods with high levels of DRS include oats and there is robust research on the many health benefits of oatmeal. Whole grains like barley are also rich in DRS. In one Japanese medical study, a diet rich in barley was able to reverse type II diabetes.
Potatoes can be a good source of DRS as well as rapidly digestible starch depending on preparation.
Raw potato is rich in DRS. DRS is destroyed in the cooking process. However, if potatoes are cooked, cooled and consumed as cold potato, the DRS is re-established. The same thing happens with rice.
Beans are also a great source of DRS. Their fermentation by the bacteria in the large bowel are the reason why some people get “gassy” after eating beans.
Science is actively researching which types of gut bacteria are important for our health. Having tasty foods in our diet that stimulate the growth of these good bacteria may reduce the incidence of chronic illnesses.
• Dr. Patrick B. Massey, MD, PH.D., is president of ALT-MED Medical and Physical Therapy, 1544 Nerge Road, Elk Grove Village. His website is www.alt-med.org.