[WAXY MAIZE STARCH] GLI INGANNI DEI PRODUTTORI SUL SUO PRESUNTO ALTO PESO MOLECOLARE
Shows Waxy Maize Starch Study Could Serve as Slow, Sustained Energy Source
Low Glycemic Carb Could Help Fuel Military Personnel, Endurance Athletes
Irvine, CA – July 30, 2009– Purdue University:
researchers may have found a new use for an old starch—waxy maize starch—to offer sustained energy delivery to military personnel and endurance athletes.
Waxy maize starch, called ‘waxy’ because of the appearance of the kernel under cross section, was brought from China to the US in the early 1900s. In the study, published in the current issue of Nutrition Research, waxy maize starch was compared to a mixture of maltodextrin and sugars, and to white bread. The study confirmed previous studies showing waxy maize starch to be slowly digested and absorbed, producing a much smaller increase in blood sugar and insulin.
“Waxy maize starch appears to provide slow, sustained delivery of energy to the body,” offered sports nutrition researcher Chad Kerksick, PhD of the University of Oklahoma Department of Health and Exercise Science. “These new findings confirm what we have seen in our study comparing waxy maize starch to maltodextrin.”
In the Purdue study twelve lean and fit young men and women received a 50 gram dose of carbohydrates supplied by white bread, waxy maize starch, or a maltodextrin and sucrose mixture (approximately 3:1 ratio), on three different days. Blood glucose and blood insulin responses to the carbohydrate sources were followed for four hours, along with measurements of calorie burning rate and subjective measurements of appetite and fullness.
The study performed an assessment of the glycemic index, a measure of the excursion of blood sugar relative to a “control” carbohydrate, white bread, and a fast digesting and absorbing carbohydrate source, maltodextrin plus sugar, at 2 and 4 hours after ingestion. At 2 hours, maltodextrin plus sugar achieved a glycemic index of 163, waxy maize starch had a value of 63, and white bread 71. The blood insulin response, influenced by how fast the carbohydrate was digested and absorbed, was 3.5 times higher, and substantially faster in the first hour with maltodextrin plus sugar, and 1.6 times higher with white bread, relative to waxy maize starch. None of the carbohydrate treatments differed in their influence on hunger, appetite, or calories burned.
“This study with waxy maize starch directly refutes what numerous sport nutrition product companies are claiming—that waxy maize starch is fast absorbing and raises insulin sharply,”described Susan Kleiner, PhD, RD, director of High Performance Nutrition, LLC in the Seattle area, and the author of the best selling book Power Eating, Third Edition. “It actually may be best suited for long endurance exercise or for persons who experience blood sugar fluctuations, as blood sugar did not drop below the starting point 4 hours after waxy maize starch but did with maltodextrin plus sugars,” added Dr. Kleiner.
“Although an exercise endurance test was not performed, we and other researchers have shown that at least over a 2 hour period, waxy maize starch does not enhance endurance performance over maltodextrin,” added Dr. Kerksick. “What would be interesting to explore is whether waxy maize starch would shine in ultra-endurance training or competition, in events lasting 4 hours or more. This may be why the military had an interest.”
This study was funded by the US Army, Natick Soldier Research Development & Engineering Center, Combat Feeding Program in Natick, MA.