Resistant Starch Linked to Changes in Fat Metabolism in Humans

These findings are significant because research has shown that impairment in fatty acid metabolism within fat cells cause excess fat storage in muscles, liver and the pancreas, which directly causes insulin resistance, a major biomarker for prediabetes.

9 Aug 2012 --- Ingredion Incorporated has announced the results of a new independent clinical trial published in the September 2012 issue of the Journal of Clinical Endocrinology & Metabolism. The principal investigator was M. Denise Robertson, Ph.D. from University of Surrey (Guildford, United Kingdom) and the funding was provided by Diabetes UK. The study showed that the consumption of HI-MAIZE resistant starch improves certain aspects of fatty acid metabolism within adipose (fat) tissue in study participants. These findings are significant because research has shown that impairment in fatty acid metabolism within fat cells cause excess fat storage in muscles, liver and the pancreas, which directly causes insulin resistance, a major biomarker for prediabetes. The findings also help explain how fat metabolism contributes to the development of prediabetes. Prediabetes is defined by the American Diabetes Association as blood glucose levels that are higher than normal but not yet high enough to be diagnosed as diabetes. The US Centers for Disease Control has estimated that nearly 80 million American adults have prediabetes.

This study showed a clear stimulatory effect on the expression of adipose tissue genes for three important enzymes [hormone-sensitive lipase (HSL), lipoprotein lipase (LPL) and adipose triglyceride lipase (ATGL)] after HI-MAIZE resistant starch consumption. HSL levels in study participants increased by 85%, LPL levels by 171% and ATGL levels by 71% versus the control. This study is also the fifth clinical study demonstrating improved insulin sensitivity (decreased insulin resistance) with HI-MAIZE resistant starch1-5. Importantly, these effects are independent of changes in caloric intake, body weight and exercise.

This randomized, single-blind, controlled crossover dietary intervention study of fifteen adults investigated the effects of dietary HI-MAIZE resistant starch in insulin resistant (but non-diabetic), moderately obese (as determined by a mean body mass index of 34) men and women, with mean age of 49 years. All study participants were considered sedentary and during the study, they maintained their normal daily activity levels.

The study participants, who consumed 40 grams of dietary fiber/day from HI-MAIZE resistant starch as a supplement to their diet for 8 weeks, experienced a 16% reduction in fasting insulin levels and 4% lower fasting glucose compared to the control that contained no resistant starch. In addition, study participants experienced a 65% increase in glucose uptake into muscles after eating and insulin sensitivity in the muscles rose 21% as measured by the euglycemic-hyperinsulinemic clamp method.

According to Dr. Christine Pelkman, Clinical Research Manager for Ingredion, "In many ways, metabolism can work against us in a vicious cycle. Improper storage of fat causes insulin resistance, which leads to more storage of fat, and more storage of fat further escalates insulin resistance. The primary recommendation to improve insulin sensitivity (and decrease insulin resistance) is to lose weight. However, according to a recent article in Health Affairs, a journal focusing on health care and public policy6, even when people are diagnosed with prediabetes, the percentage who commit to permanent lifestyle change, weight loss and maintenance of weight loss remains relatively low. The exciting news from this study is that HI-MAIZE resistant starch can give people an additional tool with which they can improve their insulin sensitivity and break the cycle."

HI-MAIZE resistant starch is made from a proprietary high amylose corn hybrid by Ingredion Incorporated. It contains approximately 40% slowly digestible (glycemic) starch and 60% resistant starch (insoluble fiber that resists digestion in the small intestine and reaches the large intestine). In the last 20 years, more than 350 published studies – including more than 90 human clinical trials – have demonstrated a range of health related benefits from the consumption of HI-MAIZE resistant starch, including assisting blood sugar and energy management, weight management and satiety in healthy individuals. It can be added to foods such as breads, baked goods and snacks by partly replacing flour or to smoothies, yogurt or oatmeal in a simple blending process.

1 Robertson MD, Wright JW, Loizon E, Debard C, Vidal H, Shojaee-Moradie F, Russell-Jones D, Umpleby AM. Insulin-sensitizing effects on muscle and adipose tissue after dietary fiber intake in men and women with metabolic syndrome. Journal of Clinical Endocrinology & Metabolism. Epub ahead of print June 28, 2012.
2 Maki KC, Pelkman CL, Finocchiaro ET, Kelley KM, Lawless AL, Schild AL, Rains TM. Resistant starch from high-amylose maize increases insulin sensitivity in overweight and obese men. Journal of Nutrition (April 2012), 142(4): 717–723.
3 Johnston KL, Thomas EL, Bell JD, Frost GS, Robertson MD. Resistant starch improves insulin sensitivity in metabolic syndrome. Diabetic Medicine (2010), 27(4): 391–397;
4 Robertson MD, Bickerton AS, Dennis AL, Vidal H, Frayn KN. Insulin-sensitizing effects of dietary resistant starch and effects on skeletal muscle and adipose tissue metabolism. American Journal of Clinical Nutrition (2005), 82(3): 559-567.
5 Robertson MD, Currie JM, Morgan LM. Jewell DP, Frayn KN. Prior short-term consumption of resistant starch enhances postprandial insulin sensitivity in healthy subjects. Diabetologia (2003), 46(5): 659-665.
6 Kahn R. Reducing the impact of diabetes: Is prevention feasible today, or should we aim for better treatment?  Health Affairs (January 2012), 31(1):76-83.