Thirty grams per day of resistant starch may improve sensitivity to insulin by a whopping 73% for men, but not women, suggests a new study from National Starch.
A lower dose of 15 grams per day of the company’s Hi-maize 260 resistant starch produced a 56% improvement in insulin sensitivity, according to findings of a trial with overweight or obese but non-diabetic male participants published inThe Journal of Nutrition.
While the improvements in insulin sensitivity are consistent with data from other studies, said the researchers, this is the first study to show improvements at a dose “as low as 15 grams per day”.
The study was funded by National Starch and scientists from the company were involved in the research.
Rhonda Witwer, senior business development manager of ntrition with National Starch Food Innovation welcomed the study’s findings: “Hi-maize resistant starch can be formulated into functional foods or added by consumers to their favorite home recipes to help maintain health blood sugar levels.
“Hi-maize resistant starch may help to shift several important hormones, including insulin, that significantly affect glucose metabolism beyond the immediate meal.”
Starches can be divided into three groups: rapidly digestible starch (RDS, digested within 20 minutes), slowly digestible starch (SDS, digested between 20 and 120 minutes), and resistant starch (RS). The latter is not digested but is fermented in the large intestine and has 'prebiotic' properties.
Resistant starch can be found naturally in cold cooked potatoes, pasta and rice as well as baked beans and lentils.
Led by Kevin Maki from Biofortis-Provident Clinical Research, the researchers recruited 33 men and women with an average age of 49.5 and an average BMI of 30.6 kg/m2.
Participants were randomly assigned to receive 0 (control starch), 15 or 30 grams per day of the Hi-maize 260 resistant starch for four week periods. The periods were separated by three week washout periods, and the participants were then randomly crossed to the remaining groups.
Results showed that men, but not women, displayed improvements in both resistant starch groups, with a 56% and 73% improvement in insulin sensitivity in the 15 and 30 grams per day groups, respectively.
The differences between men and women may be related to transit times of food through the gastrointestinal tract, differing sensitivities to the products of fermentation in the gut, or perhaps due to the stage of their menstrual cycles. However, the researchers note that it is not clear why men responded differently to women.
According to the World Health Organisation (WHO), diabetes affects over 220 million people globally and the consequences of high blood sugar kill 3.4 million every year. WHO is predicting deaths to double between 2005 and 2030.
The total costs associated with the condition in the US alone are thought to be as much as $174 billion, with $116 billion being direct costs from medication, according to 2005-2007 American Diabetes Association figures.
“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 enormous challenge,” said. Christine Pelkman, PhD, clinical research manager at National Starch and co-author of the study.
Source: The Journal of Nutrition
Published online ahead of print, doi: 10.3945/jn.111.152975
“Resistant Starch from High-Amylose Maize Increases Insulin Sensitivity in Overweight and Obese Men”
Authors: K.C. Maki, C.L. Pelkman, E.T. Finocchiaro, K.M. Kelley, A.L. Lawless, A.L. Schild, T.M. Rains