A type of starch that is resistant to (not easily broken down by) digestive enzymes, so it is absorbed much more slowly into the bloodstream than other starches. For this reason, resistant starch is used in some diabetes snack bars designed to improve blood glucose control and reduce the risk of hypoglycemia.
Both simple sugars and starches are carbohydrates–foods that get converted into glucose when they are digested. Diet experts used to think that simple sugars, because they are composed of smaller molecules, were digested and absorbed into the bloodstream more quickly than starches, which are composed of much larger molecules. We now know that this is not true and that numerous factors affect how quickly a carbohydrate is absorbed.
Certain naturally occurring starches and certain starches that have undergone special chemical processing are resistant to digestive enzymes and are absorbed more slowly than other starches. NiteBite, Gluc-O-Bar, and ExtendBar diabetes snack bars all contain uncooked cornstarch, a naturally occurring resistant starch. The Choicedm bar contains a specially processed resistant starch called CrystaLean. Another diabetes snack bar, the Glucerna bar, contains soluble fiber, which forms a viscous gel in the small intestine and slows the absorption of glucose.
Theoretically, products made with resistant starches should have a number of benefits for people with diabetes. Because the carbohydrate is absorbed so slowly, these products don’t raise blood glucose levels as quickly as other carbohydrate sources do. The slow absorption also allows glucose to continue entering the bloodstream for a long time. This can help prevent hypoglycemia, especially in the middle of the night, when most of the carbohydrates consumed in a bedtime snack would normally be used up.
Studies have suggested that diabetes snack bars may have a positive effect on blood glucose control, but the studies are not conclusive. If you’re interested in trying these products, consult your doctor or dietitian about fitting them into your meal plan, and check your blood glucose level frequently — before eating them, after eating them, and in the morning — to see what effect they’re actually having.