Resistant starch type 4 known as RS4 is not broken down in the upper gastrointestinal tract, but fermented by the gut bacteria in the colon to benefit health.
People with metabolic syndrome can improve beneficial bacteria in the gut by including resistant starch to their diets, according to research from South Dakota State University. This helps lower bad cholesterol and decrease inflammation associated with obesity. The American Heart Association estimates that 34 percent of Americans have metabolic syndrome, a combination of conditions which significantly increases their risk of developing heart disease and Type 2 diabetes.
‘Including resistant starch in the diet helps improve the balance of bacteria in the gut and decrease cholesterol levels, waist circumference and body fat percentage.’
This is the first study to examine the prebiotic impact of resistant starch type 4 known as RS4-a nondigestible, chemically modified wheat fiber-in individuals with metabolic syndrome, explained associate professor Moul Dey of the Department of Health and Nutritional Sciences. Unlike regular starch, RS4 works as a functional fiber, Dey explained. Because it is not broken down in the upper gastrointestinal tract, RS4 is fermented by the gut bacteria in the colon. This produces new substances, such as short-chain fatty acids, that have functions related to health.
"Human bodies harbor more bacterial cells than their own and therefore what we eat is not just for us but also for our bacteria," Dey said. "How well we feed them contributes to how well they take care of our health. That's where RS4 can help."
The results were published in Scientific Reports, a Nature Publishing Group academic journal. The research was supported by MGP Ingredients, the National Institutes of Health and the U.S. Department of Agriculture funding through the South Dakota Agricultural Experiment Station. Funding agencies had no role in the study design or outcome.
Using Ingredient in Real Food
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The starch was incorporated into the intervention group's flour. All the meals in this communal setting are prepared from scratch, and every meal contains one or two flour-based items.
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The intervention was conducted in two 12-week sessions with a two-week hiatus. This allowed researchers to switch the intervention and control groups so that each group served as its own control. Stool and blood samples were collected and a DXA scan to evaluate body composition was done before and after the intervention.
Doctoral candidate Bijaya Upadhyaya, master's student Robert Juenemann and postdoctoral researcher Sailendra Nichenametla worked on the research. This work also involved collaboration with U.S. Food and Drug Administration scientist Ali Reza Fardin-Kia. Other SDSU collaborators were assistant professor Lacey McCormack, professor Jeffrey Clapper of animal science and professor Bonnie Specker, director of the E.A. Martin Endowed Program in Human Nutrition.
Decreasing Cholesterol, Improving Gut Bacteria
Use of resistant starch decreased all types of cholesterols. The participants' baseline cholesterol levels were not high, in part, because of the medications they were taking. Despite that, the average total cholesterol of the participants dropped significantly after the intervention. In addition, the researchers observed a small decrease in average waist circumference and body fat percentage.
DNA analysis of stool samples using next-generation sequencing showed a change in the gut bacterial community structure after the intervention. "Essentially, consuming RS4 improved the balance of bacteria in the gut, some of which correlated with improved indicators of metabolic health as well as with increased levels of short chain fatty acids."
Currently, RS4 is only available to food manufacturers for use as a fiber ingredient. Dey hopes that one day consumers will be able to buy flour fortified with RS4.
Source-Newswise