Select Studies on Natural RS2 and RS3 resistant starches from high amylose corn

 
Select Studies on Natural RS2 and RS3 resistant starches from high amylose corn.

There is substantial research on the health benefits of resistant starches from high amylose corn (HAC), including more than 200 peer-reviewed studies published in the last 20 years.  These studies support benefits ranging from weight management, glycemic (blood sugar) management, energy management, and digestive health.  More than 75 studies in humans using RS2 and RS3 resistant starches from HAC provide confidence that the benefits from these ingredients can be reliably delivered in foods.

Just like all fibers are not the same, resistant starches are not the same.  Data confirm that different types of resistant starch impact food formulations differently, digest differently within the small intestine and ferment differently within the large intestine. Benefits demonstrated by high amylose corn resistant starches cannot be extrapolated to other types of resistant starches.  Additional research is needed to demonstrate health benefits of additional types of resistant starch. 

Below are selected key studies in key benefit areas.

1. HAC Resistant Starch & Weight Management.  HAC RS has been shown to lower the caloric density of foods, increase lipid oxidation, and increase satiety.  Animal studies suggest that it may also potentially reduce body fat and alter body composition.

Dr. Kay Behall and her colleagues at the US Department of Agriculture confirmed that high amylose corn RS2 yields between 2-3 kilocalories/gram instead of the 4 kilocalories/gram typical of flour and other high glycemic carbohydrates.  Thus, when RS2 from high amylose corn is used to replace flour, the caloric content of that food is reduced. 

A 2004 clinical study published by Dr. Janine Higgins at the University of Colorado suggests that eating a meal containing high amylose corn RS2 resistant starch increased post-prandial lipid oxidation in healthy people by 20-25%.  This study measured lipid oxidation by both indirect calorimetry (change in Respiratory Quotient) as well as the production of 14CO2 from 14C-triglycereide tracer. 

Several studies have demonstrated increased satiety following dietary consumption of RS2.  In 2009, Dr. Caroline Bodinham and her colleagues at the University of Surrey demonstrated that high amylose corn RS2 added on top of the normal diet reduced food intake by 10% over 24 hours compared to a control starch with equivalent glycemic impact.  In 2010, Dr. Harvey Anderson and his colleagues at the University of Toronto demonstrated that high amylose corn RS2 and whole grain high amylose corn RS1 reduced food intake by 7-15% two hours after consumption compared to a high glycemic control.  In this study, satiety benefits correlated with the resistant starch content, but did not correlate to the dietary fiber content of these starch-based ingredients..

Animal studies are supporting.  Dr. Mike Keenan and his colleagues at Louisiana State University demonstrated that fermentation of Hi-maize resistant starch increases the production of GLP-1 (glucagon-like peptide-1) and PYY (Peptide YY) within the large intestine. 

Animal studies suggest that high amylose corn RS2 impacts body composition.  Dr. Dorota Pawlak and her colleagues at Harvard Medical School in Boston, MA, demonstrated in 2004 that obesity-prone mice fed Hi-maize resistant starch had approximately half as much body fat after 9 weeks as obesity-prone mice consuming high glycemic cornstarch diet.  A 2008 study by the same group (Scribner, et al) found 40% less body fat, increased fat burning and 45% higher energy expenditure in Pas mice when fed Hi-maize resistant starch for 38-40 weeks.

Anderson GH, Cho CE, Akhavan T, Mollard RC, Luhovyy BL, Finocchiaro ET.  Relation between estimates of cornstarch digestibility by the Englyst in vitro method and glycemic response, subjective appetite, and short-term food intake in young men.  American Journal of Clinical Nutrition (February 17, 2010) Epub ahead of print. doi:10.3945/ajcn.2009.28443.

 [Behall KM, Howee JC. Resistant starch as energy.  The Journal of the American College of Nutrition 1996;15(3):248-54.

Bodinham CL, Frost GS, Robertson MD.  Acute ingestion of resistant starch reduces food intake in healthy adults.  British Journal of Nutrition. Epub ahead of print October 27, 2009.  doi:10.1017/S0007114509992534.  (Hi-maize 260)

Bodinham CL, Frost GS, Robertson MD (May 2008) The acute effects of resistant starch on appetite and satiety  Proc Nutr Soc 67(OCE):E157.  

Higgins JA, Higbee DR, Donahoo WT, Brown IL, Bell ML, Bessessen DH Resistant starch consumption promotes lipid oxidation.  Nutrition & Metabolism 2004;1:8.

Pawlak DB, Kushere JA, Ludwig DS.  Effects of dietary glycaemic index on adiposity, glucose homeostasis, and plasma lipids in animals.  Lancet.  2004;364:778-85.

Scribner KB, Pawlak DB, Aubin CM, Majzoub JA, Ludwig DS (Sept 9, 2008) Long-term effects of dietary glycemic index on adiposity, energy metabolism and physical activity in mice.  Am J Physiol Endocrinol Metab [Epub ahead of print]   doi:10.1152/ajpendo.90487.2008.

Zhou J, Martin RJ, Tulley RT, Raggio AM, McCutcheon KL, Shen L, Danna SC, Tripathy S, Hegsted M, Keenan MJ (September 16, 2008) Dietary resistant starch up-regulates total GLP-1 and PYY in a sustained daylong manner through fermentation in rodents  Am J Physiol Endocrinol Metab. [Epub ahead of print]  doi: 10.1152/ajpendo.90637.2008.]