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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.

Edwards CH, Grundy MM, Grassby T, Vasilopoulou D, Frost GS, Butterworth PJ, Berry SE, Sanderson J, Ellis PR - Am. J. Clin. Nutr. (2015)

Bottom Line: 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.The structure of the test meal had no effect on the amount or pattern of RS output.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.

View Article: PubMed Central - PubMed

Affiliation: Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom;

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.

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Related in: MedlinePlus

Postprandial changes in blood glucose (A), insulin (B), C-peptide (C), and GIP (D) concentrations after smooth and coarse porridge meals. Each meal provided 55.4 g of starch. Values are mean deviations from baseline ± SEMs (n = 9 for glucose, insulin, and C-peptide and n = 8 for GIP) and were analyzed by ANOVA with meal and time as factors. Meal, time, and meal × time were significant for glucose (P = 0.038, <0.001, and <0.001), insulin (P = 0.046, <0.001, and 0.035), C-peptide (P = 0.018, <0.001, and <0.001), and GIP (P = 0.024, <0.001, and <0.001) responses, respectively. Time points at which values differed significantly, *P < 0.05, **P < 0.01, and ***P < 0.001 (paired t test with Bonferroni corrections). Insets show the iAUC between 0 and 120 min. GIP, glucose-dependent insulinotropic polypeptide; iAUC, incremental AUC.
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fig3: Postprandial changes in blood glucose (A), insulin (B), C-peptide (C), and GIP (D) concentrations after smooth and coarse porridge meals. Each meal provided 55.4 g of starch. Values are mean deviations from baseline ± SEMs (n = 9 for glucose, insulin, and C-peptide and n = 8 for GIP) and were analyzed by ANOVA with meal and time as factors. Meal, time, and meal × time were significant for glucose (P = 0.038, <0.001, and <0.001), insulin (P = 0.046, <0.001, and 0.035), C-peptide (P = 0.018, <0.001, and <0.001), and GIP (P = 0.024, <0.001, and <0.001) responses, respectively. Time points at which values differed significantly, *P < 0.05, **P < 0.01, and ***P < 0.001 (paired t test with Bonferroni corrections). Insets show the iAUC between 0 and 120 min. GIP, glucose-dependent insulinotropic polypeptide; iAUC, incremental AUC.

Mentions: Plasma glucose (0–120 min), serum insulin, C-peptide, and plasma GIP concentrations were significantly lower after the coarse porridge (i.e., made with low-bioaccessibility starch) than after the smooth porridge containing high-bioaccessibility starch (Figure 3). A main meal effect was found over 120 min for glucose (P = 0.038) and over 240 min for insulin (P = 0.046), C-peptide (P = 0.018), and GIP (P = 0.024), but not for glucose (P = 0.229). Also, significant meal × time interactions over 240 min were observed for glucose (P < 0.001), insulin (P = 0.035), C-peptide (P < 0.001), and GIP (P < 0.001). After 120 min, the incremental AUC for glucose, insulin, C-peptide and GIP were 33%, 43%, 40%, and 50% lower (P < 0.01), respectively, after consumption of coarse porridge than after smooth porridge. The smooth porridge, which consisted of highly bioaccessible starch, elicited a rapid and large glycemic response within the first 60 min, followed by a reduction in glucose with an overshoot to nearly 1 mmol/L below the fasting value. In contrast, the coarse porridge elicited a smaller rise in blood glucose and insulin concentrations, with a much slower rate of decline after 90 min; indeed, the glucose concentrations remained above fasting even after 4 h. The peak concentrations of glucose, insulin, C-peptide, and GIP were 12%, 32%, 37%, and 60% higher (P < 0. 01), respectively, after smooth than after coarse porridge and were reached within 90 min of ingesting the test meals.


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.

Edwards CH, Grundy MM, Grassby T, Vasilopoulou D, Frost GS, Butterworth PJ, Berry SE, Sanderson J, Ellis PR - Am. J. Clin. Nutr. (2015)

Postprandial changes in blood glucose (A), insulin (B), C-peptide (C), and GIP (D) concentrations after smooth and coarse porridge meals. Each meal provided 55.4 g of starch. Values are mean deviations from baseline ± SEMs (n = 9 for glucose, insulin, and C-peptide and n = 8 for GIP) and were analyzed by ANOVA with meal and time as factors. Meal, time, and meal × time were significant for glucose (P = 0.038, <0.001, and <0.001), insulin (P = 0.046, <0.001, and 0.035), C-peptide (P = 0.018, <0.001, and <0.001), and GIP (P = 0.024, <0.001, and <0.001) responses, respectively. Time points at which values differed significantly, *P < 0.05, **P < 0.01, and ***P < 0.001 (paired t test with Bonferroni corrections). Insets show the iAUC between 0 and 120 min. GIP, glucose-dependent insulinotropic polypeptide; iAUC, incremental AUC.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4588739&req=5

fig3: Postprandial changes in blood glucose (A), insulin (B), C-peptide (C), and GIP (D) concentrations after smooth and coarse porridge meals. Each meal provided 55.4 g of starch. Values are mean deviations from baseline ± SEMs (n = 9 for glucose, insulin, and C-peptide and n = 8 for GIP) and were analyzed by ANOVA with meal and time as factors. Meal, time, and meal × time were significant for glucose (P = 0.038, <0.001, and <0.001), insulin (P = 0.046, <0.001, and 0.035), C-peptide (P = 0.018, <0.001, and <0.001), and GIP (P = 0.024, <0.001, and <0.001) responses, respectively. Time points at which values differed significantly, *P < 0.05, **P < 0.01, and ***P < 0.001 (paired t test with Bonferroni corrections). Insets show the iAUC between 0 and 120 min. GIP, glucose-dependent insulinotropic polypeptide; iAUC, incremental AUC.
Mentions: Plasma glucose (0–120 min), serum insulin, C-peptide, and plasma GIP concentrations were significantly lower after the coarse porridge (i.e., made with low-bioaccessibility starch) than after the smooth porridge containing high-bioaccessibility starch (Figure 3). A main meal effect was found over 120 min for glucose (P = 0.038) and over 240 min for insulin (P = 0.046), C-peptide (P = 0.018), and GIP (P = 0.024), but not for glucose (P = 0.229). Also, significant meal × time interactions over 240 min were observed for glucose (P < 0.001), insulin (P = 0.035), C-peptide (P < 0.001), and GIP (P < 0.001). After 120 min, the incremental AUC for glucose, insulin, C-peptide and GIP were 33%, 43%, 40%, and 50% lower (P < 0.01), respectively, after consumption of coarse porridge than after smooth porridge. The smooth porridge, which consisted of highly bioaccessible starch, elicited a rapid and large glycemic response within the first 60 min, followed by a reduction in glucose with an overshoot to nearly 1 mmol/L below the fasting value. In contrast, the coarse porridge elicited a smaller rise in blood glucose and insulin concentrations, with a much slower rate of decline after 90 min; indeed, the glucose concentrations remained above fasting even after 4 h. The peak concentrations of glucose, insulin, C-peptide, and GIP were 12%, 32%, 37%, and 60% higher (P < 0. 01), respectively, after smooth than after coarse porridge and were reached within 90 min of ingesting the test meals.

Bottom Line: 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.The structure of the test meal had no effect on the amount or pattern of RS output.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.

View Article: PubMed Central - PubMed

Affiliation: Biopolymers Group, Diabetes and Nutritional Sciences Division, King's College London, London, United Kingdom;

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.

Show MeSH
Related in: MedlinePlus