Eating between meals can trip up people trying to limit their food consumption. Those extra, unplanned snacks add calories, complicate weight maintenance and slow progress in the battle of the bulge. If only such “hunger pains” could be staved off. If only satiety could be prolonged after a meal.
Current nutritional studies using resistant starch suggest that this food component may be a potent weapon in curbing the habit of eating between meals and, thus, combating obesity. In a clinical study, a University of Toronto research team led by satiety expert G. Harvey Anderson, PhD, found that the quantity of resistant starch in foods correlates with blood glucose response and reduced food intake after two hours (published Feb. 17, 2010, ahead of print, by the American Journal of Clinical Nutrition). The team used Hi-maize whole-grain corn flour and Hi-maize resistant starch produced by National Starch Food Innovation (NSFI), Bridgewater, NJ.
“This study suggests a dose response for resistant starch and satiety because of this positive correlation,” Dr. Anderson said.
“This is the first time that resistant starch content alone has been shown to have a satiety effect,” said Rhonda Witwer, senior business development manager, nutrition, NSFI. Hi-maize resistant starch is a natural starch from corn that “resists” digestion in the small intestine. It is classified as an RS2 resistant starch, which means it maintains its natural starch granule. Food sources of RS2 include bananas, raw potatoes and high-amylose corn.
Resistant starch is a form of dietary fiber and has been the subject of several previous studies pointing to both long-term and short-term satiety effects of RS2 resistant statch. Satiety is the effect after eating that impacts subsequent feelings of hunger, fullness and, in due course, the amount of food you eat at your next meal or snack.
Dr. Anderson and his team measured effects on a motivation-to-eat visual analog scale (“not very full” to “very full”) at various times. That satiety was felt at the 2-hour point after eating resistant starch leads to the theory that this form of fiber is active lower in the small intestine than more rapidly digested carbohydrates and before other forms of dietary fiber. Previous studies with resistant starch found increased satiety after 7, 10.5 and even 24 hours.
“The Anderson study begins to explain why earlier reports about fiber, resistant starch and satiety are so different in their results,” Ms. Witwer said. It suggests that the biological reactions fostering satiety occur earlier during digestion than previously recognized. “We think bioactivity in the small intestine, an effect of resistant starch, is as important in satiety as the bioactivity in the large intestine, where dietary fiber comes into play,” she explained. “This work will spark a lot of new research.”
Additional papers and presentations are available at www.resistantstarch.com and www.5-in-1-fiber.com. Research continues, and Ms. Witwer noted that the National Institutes of Health are doing a Hi-maize study in California, looking at metabolism biomarkers and insulin sensitivity.
Is there a threshold amount of resistant starch that produces such results? The Anderson study used 50 g per serving in tomato soup fed to healthy young men (ages 20 to 30 years) two hours after consuming a standard breakfast. Another study put 8.0 to 9.6 g of various dietary fibers, including resistant starch, per serving into corn muffi ns, eaten at breakfast. The resistant starch had the strongest impact on satiety after three hours, compared with the other types of fibers, demonstrating that not all fibers are the same.
“Researchers tend to approach the threshold question in stages,” Ms. Witwer said. “After determining there is a measurable effect, they usually test it further by changing the dose per serving. Satiety studies are so new that threshold amounts are still being determined.”
Hi-maize 260, the form used in the Anderson study, is a granular resistant starch containing 60% total dietary fiber. It can be used in a variety of baked foods including bread, rolls, cakes, cookies, crackers, pasta, ready-to-eat breakfast cereals, waffles and similar products. When balancing a formula containing resistant starch, the quantity of the starch should be deducted from the amount of flour in the starting formula, and vital wheat gluten can be added to compensate for the subtracted flour’s gluten. In the finished products, dietary fiber content ranges from 8 g per 100 g in biscuits, to 9 g in pasta, to 12 g in high-fiber whole-wheat bread, according to formulations supplied by NSFI. On food labels, the resistant starch can be described simply as “corn starch” or “resistant corn starch.”
Hunger management via food choice is a new hot topic for food R&D in the area of weight management. The immediate goal is to promote satiety, so the consumer feels less hungry, with the ultimate goal of reducing food intake as means of combating obesity.