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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 serum TAG (A) and NEFA (B) concentrations after smooth and coarse porridge meals. Each meal provided 1.56 g fat. Values are mean deviations from baseline ± SEMs (n = 9) and were analyzed by ANOVA with meal and time as factors. Time effects were highly significant for both TAGs (P = 0.004) and NEFAs (P < 0.001), but meal and meal × time were not significant (P = 0.074 and 0.100 for TAGs and P = 0.969 and 0.249 for NEFAs). NEFA, nonesterified fatty acid; TAG, triacylglycerol.
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fig4: Postprandial changes in serum TAG (A) and NEFA (B) concentrations after smooth and coarse porridge meals. Each meal provided 1.56 g fat. Values are mean deviations from baseline ± SEMs (n = 9) and were analyzed by ANOVA with meal and time as factors. Time effects were highly significant for both TAGs (P = 0.004) and NEFAs (P < 0.001), but meal and meal × time were not significant (P = 0.074 and 0.100 for TAGs and P = 0.969 and 0.249 for NEFAs). NEFA, nonesterified fatty acid; TAG, triacylglycerol.

Mentions: The pattern of triacylglycerol and NEFA responses after the test meals (1.56 g fat) are shown in Figure 4. After both meals, serum NEFA concentrations decreased from fasting concentration within the first 60 min, then gradually increased again toward the end of the 4-h time period. A gradual reduction in serum triacylglycerols was also observed. The effect of time on triacylglycerol and NEFA concentrations was statistically significant (P = 0.04 and P < 0.001, respectively). Statistical analysis showed that the test meals had no effect on the pattern of the response curves (meal × time effect, P = 0.100 for triacylglycerols and P = 0.249 for NEFAs); however, there was a tendency toward a lower triacylglycerol response after the coarse porridge (Figure 4A).


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 serum TAG (A) and NEFA (B) concentrations after smooth and coarse porridge meals. Each meal provided 1.56 g fat. Values are mean deviations from baseline ± SEMs (n = 9) and were analyzed by ANOVA with meal and time as factors. Time effects were highly significant for both TAGs (P = 0.004) and NEFAs (P < 0.001), but meal and meal × time were not significant (P = 0.074 and 0.100 for TAGs and P = 0.969 and 0.249 for NEFAs). NEFA, nonesterified fatty acid; TAG, triacylglycerol.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig4: Postprandial changes in serum TAG (A) and NEFA (B) concentrations after smooth and coarse porridge meals. Each meal provided 1.56 g fat. Values are mean deviations from baseline ± SEMs (n = 9) and were analyzed by ANOVA with meal and time as factors. Time effects were highly significant for both TAGs (P = 0.004) and NEFAs (P < 0.001), but meal and meal × time were not significant (P = 0.074 and 0.100 for TAGs and P = 0.969 and 0.249 for NEFAs). NEFA, nonesterified fatty acid; TAG, triacylglycerol.
Mentions: The pattern of triacylglycerol and NEFA responses after the test meals (1.56 g fat) are shown in Figure 4. After both meals, serum NEFA concentrations decreased from fasting concentration within the first 60 min, then gradually increased again toward the end of the 4-h time period. A gradual reduction in serum triacylglycerols was also observed. The effect of time on triacylglycerol and NEFA concentrations was statistically significant (P = 0.04 and P < 0.001, respectively). Statistical analysis showed that the test meals had no effect on the pattern of the response curves (meal × time effect, P = 0.100 for triacylglycerols and P = 0.249 for NEFAs); however, there was a tendency toward a lower triacylglycerol response after the coarse porridge (Figure 4A).

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