Resistant starch improves GI of foods – more support

Scientists from Kansas State University report that resistant starch in a nutrition bar formulated with brown sugar and corn syrup was associated with reduced glycaemic responses, according to findings published in the Journal of Nutrition and Metabolism​.

Results of the small study, which included only 11 participants, build the science behind resistant starch ingredients. The new study used MGP Ingredients' Fibersym RW-branded ingredient.

Resistant starch (RS) is so called because of its ability to resist digestion in the small intestine, unlike most other starches. Instead, RS passes through to the large intestine where it acts like dietary fibre and improves digestive health.

Resistant starch occurs naturally in foods such as unripe bananas and cooked and cooled potatoes, but commercially produced RS ingredients have started to appear on the market in order to allow food manufacturers to incorporate the ingredient into their products.

This has provided the industry with another means to tap into opportunities gleaned from the growing trend for health and wellness foods, with resistant starch fitting squarely into the low-glycaemic food trend, as well as health product positioning such as prebiotic fibre and healthy digestive system claims.

Companies like National Starch with its Hi-Maize ingredient, which is derived from corn, have been very active in building the science behind the ingredient.

Study details​

Led by KSU’s Mark Haub, the researcher recruited 11 healthy adults and fed 30 grams of carbohydrate in as three types of beverages: One was a dextrose beverage (Sun-Dex), another was water with resistant starch type 2 (Hi-Maize 260), while the third was water plus the cross-linked resistant wheat starch (Fibersym RW).

The researchers report that, following consumption, “both types of RS in the present study attenuated the glucose response compared with the same amount of dextrose”.​

“However, these data indicate that not all resistant starch types elicit similar glucose responses, as the [cross-linked type] response was less than,”​ wrote the researchers.

“A reason for this observation is likely that [cross-linked resistant starch] contains a greater degree of dietary fibre (91.9 per cent) and more RS (83 per cent) compared with the fibre (60 per cent) and RS content (46 per cent) of the version of resistant starch type 2 that was used,”​ they said.

“One surprising and useful outcome of the study was that Fibersym RW significantly attenuated the glycemic and insulinemic responses even when high glycemic ingredients such as brown sugar and corn syrup represented 31 per cent of the nutritional bar formula,”​ said Haub.

Both Dr Haub and Dr Seib declare receiving funding support from MGP Ingredients.

Source: Journal of Nutrition and Metabolism​
​Volume 2010, Article ID 230501, doi:10.1155/2010/230501
“Different Types of Resistant Starch Elicit Different Glucose Reponses in Humans”​
Authors: M.D. Haub, K.L. Hubach, E.K. Al-tamimi, S. Ornelas, P.A. Seib
Full text available here​.