Resistant starch tolerates processing, including extrusion and baking, and this allows its addition to oat clusters to boost their fiber content.

Because most Americans consume baked foods and snacks on a daily basis, these products provide an ideal platform for nutritional enhancement to improve the overall health and wellness of the population. That’s the reason behind the mandate that refined flour be enriched. It’s also a good justification for voluntary addition of dietary fiber.

For one thing, such fibers replace digestible starches in baked foods, crackers and pasta. “Compared with ­conventional products, foods made with resistant starch can help manage blood sugar levels,” said Maria Stewart, PhD, clinical research lead, global nutrition R&D, Ingredion. “High-amylose corn resistant starch has also been shown to improve insulin sensitivity and carbohydrate metabolism.” Those two effects alone are key to reducing the risk and helping management of type 2 diabetes.

Maria Tolchinsky, senior business development manager, global nutrition, Ingredion, Inc., noted that Ingredion’s Hi-Maize resistant starch is backed by clinical research “showing digestive and blood sugar management effects when substituted for other high-glycemic ingredients in food systems.”

A recent 26-week human clinical study showed that resistant wheat starch reduced the risk factors for metabolic syndrome. According to Ody Maningat, PhD, cheif science officer, MGP Ingredients, this is "defined as a cluster of risk factors (abdominal obesity, high blood cholesterol levels, high blood glucose levels, elevated blood pressure and high triglycerides) that raise an individual’s chance of developing heart disease, stroke and type 2 diabetes.”

He added, “Wheat resistant starch has proven beneficial physiological effects in humans as shown by five independent studies from Kansas State University, South Dakota State University and the University of Nebraska.”

Recent attention to satiety effects caused by various food ingredients has also highlighted the role played by dietary fiber. Michelle Kozora, technical services manager, Cargill, quoted a 2010 study from Canada that found the ability of resistant starch to promote the feeling of fullness depends on the size of the dose, the amount in the food as consumed. “There’s been some research on this topic,” she said, “but more is needed.”

Doris Dougherty, technical service representative, Fibersol, noted that studies done with the company’s soluble vegetable fiber derived from corn found it can provide an increased feeling of satiety, leaving consumers feeling fuller for longer periods of time. “Research has shown consumption of 10 g Fibersol-2 with a meal can increase production of certain satiety hormones and delay hunger,” she said.

Resistant starch qualifies as a prebiotic and, thus, can play an important role in digestive health. “Research on the health benefits of resistant starch is still evolving,” Dr. Stewart said. “A few of the hot trends in this area include the effect of resistant starch on the immune system, inflammation and colonic bacteria, also known as the ‘gut microbiome.’ ”

It is termed “resistant” because it is not digested in the stomach or small intestine in a way that breaks down the starch’s carbohydrate moieties into glucose to fuel by the body. Instead, it reaches the large intestine intact, where it is fermented by bacteria, and the chief product of this reaction is butyrate, a short-chain fatty acid.

“When resistant starch reaches the colon, it is degraded by the resident bacteria,” Dr. Stewart explained. “These bacteria create beneficial metabolites known as short-chain fatty acids, which improve digestive health. Short-chain fatty acids also impact broader ­metabolic effects, which may be the key mediator between resistant starch intake and improved human health.”