Efficacy of increased resistant starch consumption in human type 2 diabetes

Abstract

Resistant starch (RS) has been shown to beneficially affect insulin sensitivity in healthy individuals and those with metabolic syndrome, but its effects on human type 2 diabetes (T2DM) are unknown. This study aimed to determine the effects of increased RS consumption on insulin sensitivity and glucose control and changes in postprandial metabolites and body fat in T2DM. Seventeen individuals with well-controlled T2DM (HbA1c 46.6±2 mmol/mol) consumed, in a random order, either 40 g of type 2 RS (HAM-RS2) or a placebo, daily for 12 weeks with a 12-week washout period in between. At the end of each intervention period, participants attended for three metabolic investigations: a two-step euglycemic–hyperinsulinemic clamp combined with an infusion of [6,6-2H2] glucose, a meal tolerance test (MTT) with arterio-venous sampling across the forearm, and whole-body imaging. HAM-RS2 resulted in significantly lower postprandial glucose concentrations (P=0.045) and a trend for greater glucose uptake across the forearm muscle (P=0.077); however, there was no effect of HAM-RS2 on hepatic or peripheral insulin sensitivity, or on HbA1c. Fasting non-esterified fatty acid (NEFA) concentrations were significantly lower (P=0.004) and NEFA suppression was greater during the clamp with HAM-RS2 (P=0.001). Fasting triglyceride (TG) concentrations and soleus intramuscular TG concentrations were significantly higher following the consumption of HAM-RS2 (P=0.039 and P=0.027 respectively). Although fasting GLP1 concentrations were significantly lower following HAM-RS2 consumption (P=0.049), postprandial GLP1 excursions during the MTT were significantly greater (P=0.009). HAM-RS2 did not improve tissue insulin sensitivity in well-controlled T2DM, but demonstrated beneficial effects on meal handling, possibly due to higher postprandial GLP1.

A Randomised Crossover Trial: The Effect of Inulin on Glucose Homeostasis in Subtypes of Prediabetes

“…Interestingly, resistant starch supplementation increases peripheral glucose uptake in healthy subjects and in subjects with the metabolic syndrome [37] ; yet, a subsequent study by the same authors found no effect using the same method in subjects with DMT2 [38] , a finding that supports earlier work indicating that the underlying pathophysiology of diabetes may attenuate the effect of FCHO on glucose metabolism [39] . We have recently shown that over 9 weeks, the same dose of inulin as used in this study (30 g/day) reduces FPG in subjects with prediabetes compared to control [unpublished data], suggesting that longer supplementation periods may be required in subjects with prediabetes or DMT2.…”

“…We have recently shown that over 9 weeks, the same dose of inulin as used in this study (30 g/day) reduces FPG in subjects with prediabetes compared to control [unpublished data], suggesting that longer supplementation periods may be required in subjects with prediabetes or DMT2. Nevertheless, the effect of FCHO on glucose metabolism is clearly complex, with the type of FCHO (resistant starch, fructooligosaccharides, lactulose or inulin) [7,8,32] , the SCFA ratio produced [40] , and underlying pathophysiology [38,39] all appearing to mediate the effect of FCHO. We would draw particular attention to establish in vivo, the metabolic fate of the SCFAs: randomized controlled trials have shown that oral propionate lowers fasting and postprandial glucose [41,42] ; yet acute gastric infusion of propionate has no effect on hepatic glucose production or glucose levels [43] .…”

Characterization and Prebiotic Effect of the Resistant Starch from Purple Sweet Potato

“…Resistant starch has been proved to exhibit potential health benefits, including reducing the glycemic response [6], lowering blood cholesterol [7], acting as a functional probiotic [8], and increasing the production of short chain fatty acids in the large intestine [9].…”

Reevaluating the hype: four bacterial metabolites under scrutiny

“…However, the unphysiologically high concentrations of sodium propionate applied in these studies advise caution. Bodinham et al [156] recently studied the effects of increased resistant starch consumption in type-2 diabetes patients. While insulin sensitivity did not improve, a benefi cial effect on meal handling behavior was observed.…”

“…Moreover, many studies performed in humans used a SCFA mix [161] or prebiotics such as resistant starch [156]. In consequence, it is not possible to separate the effects of the SCFAs and to analyze any synergistic or antagonistic actions.…”