Researchers reporting in the November, 2008 issue of the American Journal of Physiology, Endocrinology and Metabolism, found improvements in blood glucose levels in mice fed resistant starch.1Resistant starch (RS) is simply starch that resists digestion and travels to the colon where it undergoes fermentation by resident bacteria.
It is the fermentation of that starch that is thought to offer benefit.
During fermentation, colonic bacteria produce short chain fatty acids (SCFAs). These SCFAs were found to stimulate secretion of two gut hormones: Glucagon-like peptide-1 (GLP-1) and peptide YY (PYY).
These hormones can slow gastric emptying and encourage insulin secretion - keeping blood glucose levels in check. They are also know to reduce appetite.
Specifically, the authors found that:
- RS stimulates GLP-1 and PYY secretion in a substantial day-long manner, independent of meal effect or changes in dietary glycemia.
- Fermentation and the liberation of SCFAs in the lower gut are associated with increased proglucagon and PYY gene expression.
- Glucose tolerance, an indicator of increased active forms of GLP-1 and PYY, was improved in RS-fed diabetic mice.
Food Sources For Resistant Starch
The HealthyEatingClub.com lists these foods as containing resistant starch:
- Intact wholegrain cereals/seeds/nuts, e.g. oats, rye, wheat, barley, semolina, corn, linseed, sesame
- Processed starchy foods, e.g. some breakfast cereals (cornflakes), white bread, rice, pasta
- Processed starchy foods with added RS called Hi-Maize (derived from corn)
- Legumes, e.g. lentils, beans (Legumes have the highest content of RS.)
- Unripe fruit, especially banana
- Cooked cold rice, cold pasta salad, cold boiled potato salad (Cooking and cooling food can increase RS content.)
