The evidence indicates resistant starches improve glucose metabolism beyond what would be expected from its reduced glycemic index.
The healthcare profession is well aware of the global rise in obesity levels and the corresponding negative health consequences. The leading risk factor for many metabolic diseases, including cardiovascular disease and type 2 diabetes, is abdominal adiposity. For more than 30 years, researchers have been investigating metabolic resistant starches’ ability to treat obesity.
Metabolic resistant starches are the starches (including degradation products) that elude digestion in healthy adults' small intestines. There are four types of resistant starches:
Non-digestible resistant starches, when used as replacement products in baked goods. reduce the food's calorie density and glycemic index.
The journal Current Opinions in Clinical Nutrition Metabolic Care has published a review ahead-of-print that surveys current knowledge regarding metabolic resistant starches.
The authors highlight a number of key points. First, in addition to dodging digestion, resistant starches can positively affect dyslipidemia and insulin sensitivity (without impacting body composition). Researchers have noted that on rats, consumption of resistant starches improves body composition—body fat depots decline. Resistant starches also modulate satiety.
Second, researchers believe that two pathways — gut microbiota-independent and gut microbiota-dependent – contribute to these metabolic benefits. However the roles of these two pathways are poorly understood.
Third, while researchers have observed inconsistencies across species (and across individual humans), these may be explained by multiple factors including differences among microbiota, varying levels of resistant starch intake, and disease status. Variations among resistant start structures could also explain discrepancies.
In summary, the authors say evidence indicates resistant starches improve glucose metabolism beyond what would be expected from its reduced glycemic index. They note that the extent to which established pathologies can be reversed is still unclear, and some studies do not show a beneficial effect on glycemic variables.