Resistant Starch and Insulin Sensitivity
In a presentation given at Experimental Biology 2011 in Washington, D.C., on April 10, study leader Kevin C. Maki, Ph.D. of Biofortis-Provident Clinical Research (Glen Ellyn, Ill.) reported that overweight or obese but non-diabetic male participants taking part in a clinical study showed a 72.7% improvement in insulin sensitivity after receiving a 30g/day (d) dose of resistant starch from Hi-maize 260, and a 56.5% improvement in insulin sensitivity from a 15g/d dose. While a positive insulin sensitivity effect has been reported in previous trials with Hi-maize resistant starch, this was the first study to examine the lower dose of 15g/d.
The Centers for Disease Control has estimated that nearly 80 million American adults have prediabetes. Studies such as the National Institutes of Health’s Diabetes Prevention Program have demonstrated that intensive lifestyle intervention, including minimal weight loss and regular physical activity, can effectively increase insulin sensitivity and help to maintain blood sugar levels within the normal range. The study by Maki suggests that dietary consumption of modest levels of Hi-maize resistant starch on a regular basis can help individuals at risk for prediabetes maintain healthy blood sugar levels.
According to Dr. Christine Pelkman, clinical research manager for National Starch and co-author on the study, “There is good evidence that minimal weight loss and increased physical activity can help to preserve healthy blood sugar levels. But in the U.S., we seem to be moving in the opposite direction. The number of overweight and obese people in this country is increasing, and even when people are diagnosed with prediabetes, the percentage of people who commit to permanent lifestyle change is relatively low. With the costs in human suffering and medical treatment associated with high blood sugar levels, we should be doing everything we can to meet this burgeoning challenge.”
The Maki study on Hi-maize resistant starch was a randomized, double-blind, controlled, crossover trial consisting of three four-week treatment periods, separated by three-week washouts. Participants were overweight and obese men and women, 18-69 years of age with elevated waist circumference: a marker for insulin sensitivity. They consumed either 15 or 30g/d of resistant starch (measured as dietary fiber) from Hi-maize resistant starch, with a control starch including no resistant starch. Insulin sensitivity index was assessed at the end of each period using an insulin-modified intravenous glucose tolerance test (minimal model). The men experienced a statistically significant average improvement in insulin sensitivity of 56.5% and 72.7% for the low- and high-dose treatments, respectively. In contrast, the same study did not find an improvement in insulin sensitivity in overweight women. The authors suggested that responses in women might have differed, as they were less insulin-resistant at baseline and changes over the menstrual cycle may have obscured the effects.
From the May 24, 2011, Prepared Foods' Daily News.