Manipulation of starch bioaccessibility in wheat endosperm to regulate starch digestion, postprandial glycemia, insulinemia, and gut hormone responses: a randomized controlled trial in healthy ileostomy participants
Author(s)
Type
Journal Article
Abstract
Background: Cereal crops, particularly wheat, are a major dietary source of starch, and the bioaccessibility of starch has implications for postprandial glycemia. The structure and properties of plant foods have been identified as critical factors in influencing nutrient bioaccessibility; however, the physical and biochemical disassembly of cereal food during digestion has not been widely studied.
Objectives: The aims of this study were to compare the effects of 2 porridge meals prepared from wheat endosperm with different degrees of starch bioaccessibility on postprandial metabolism (e.g., glycemia) and to gain insight into the structural and biochemical breakdown of the test meals during gastroileal transit.
Design: A randomized crossover trial in 9 healthy ileostomy participants was designed to compare the effects of 55 g starch, provided as coarse (2-mm particles) or smooth (<0.2-mm particles) wheat porridge, on postprandial changes in blood glucose, insulin, C-peptide, lipids, and gut hormones and on the resistant starch (RS) content of ileal effluent. Undigested food in the ileal output was examined microscopically to identify cell walls and encapsulated starch.
Results: Blood glucose, insulin, C-peptide, and glucose-dependent insulinotropic polypeptide concentrations were significantly lower (i.e., 33%, 43%, 40%, and 50% lower 120-min incremental AUC, respectively) after consumption of the coarse porridge than after the smooth porridge (P < 0.01). In vitro, starch digestion was slower in the coarse porridge than in the smooth porridge (33% less starch digested at 90 min, P < 0.05, paired t test). In vivo, the structural integrity of coarse particles (∼2 mm) of wheat endosperm was retained during gastroileal transit. Microscopic examination revealed a progressive loss of starch from the periphery toward the particle core. The structure of the test meal had no effect on the amount or pattern of RS output.
Conclusion: The structural integrity of wheat endosperm is largely retained during gastroileal digestion and has a primary role in influencing the rate of starch amylolysis and, consequently, postprandial metabolism. This trial was registered at isrctn.org as ISRCTN40517475.
Objectives: The aims of this study were to compare the effects of 2 porridge meals prepared from wheat endosperm with different degrees of starch bioaccessibility on postprandial metabolism (e.g., glycemia) and to gain insight into the structural and biochemical breakdown of the test meals during gastroileal transit.
Design: A randomized crossover trial in 9 healthy ileostomy participants was designed to compare the effects of 55 g starch, provided as coarse (2-mm particles) or smooth (<0.2-mm particles) wheat porridge, on postprandial changes in blood glucose, insulin, C-peptide, lipids, and gut hormones and on the resistant starch (RS) content of ileal effluent. Undigested food in the ileal output was examined microscopically to identify cell walls and encapsulated starch.
Results: Blood glucose, insulin, C-peptide, and glucose-dependent insulinotropic polypeptide concentrations were significantly lower (i.e., 33%, 43%, 40%, and 50% lower 120-min incremental AUC, respectively) after consumption of the coarse porridge than after the smooth porridge (P < 0.01). In vitro, starch digestion was slower in the coarse porridge than in the smooth porridge (33% less starch digested at 90 min, P < 0.05, paired t test). In vivo, the structural integrity of coarse particles (∼2 mm) of wheat endosperm was retained during gastroileal transit. Microscopic examination revealed a progressive loss of starch from the periphery toward the particle core. The structure of the test meal had no effect on the amount or pattern of RS output.
Conclusion: The structural integrity of wheat endosperm is largely retained during gastroileal digestion and has a primary role in influencing the rate of starch amylolysis and, consequently, postprandial metabolism. This trial was registered at isrctn.org as ISRCTN40517475.
Date Issued
2015-09-02
Date Acceptance
2015-07-31
Citation
American Journal of Clinical Nutrition, 2015, 102 (4), pp.791-800
ISSN
1938-3207
Publisher
American Society for Nutrition
Start Page
791
End Page
800
Journal / Book Title
American Journal of Clinical Nutrition
Volume
102
Issue
4
Copyright Statement
This is an open access article distributed under the CC-BY license (http://creativecommons.org/licenses/by/3.0/).
License URL
Sponsor
National Institute for Health Research
Biotechnology and Biological Sciences Research Council (BBSRC)
Biotechnology and Biological Sciences Research Council (BBSRC)
Grant Number
NF-SI-0508-10112
BB/L004259/1
BB/L025582/1
Subjects
Science & Technology
Life Sciences & Biomedicine
Nutrition & Dietetics
ileostomy
starch
postprandial
glycemia
bioaccessibility
structure
digestion
HUMAN SMALL-INTESTINE
LIPID BIOACCESSIBILITY
METABOLIC RESPONSES
CARBOHYDRATE FOODS
ENERGY VALUES
ALPHA-AMYLASE
ALMOND SEEDS
CELL-WALLS
APPETITE
DIETS
Adult
Aged
Blood Glucose
Body Mass Index
C-Peptide
Cross-Over Studies
Dietary Carbohydrates
Digestion
Endosperm
Fatty Acids, Nonesterified
Female
Gastric Inhibitory Polypeptide
Gastrointestinal Hormones
Healthy Volunteers
Humans
Ileostomy
Insulin
Male
Middle Aged
Postprandial Period
Starch
Triglycerides
Triticum
Young Adult
11 Medical And Health Sciences
09 Engineering
Publication Status
Published