The effects of soluble corn fibre and isomaltooligosacharides on blood glucose, insulin, digestion and fermentation in healthy young males and females

Abstract

Dietary fibre refers to nutrients in the diet that gastrointestinal enzymes do not digest. If properly labelled, dietary fibres should not significantly elevate blood glucose or insulin and should ferment in the large intestine. Because of the recent rise in low-carbohydrate products on the market, consumers use these various fibres without adequate knowledge concerning whether or not these ingredients affect any blood parameters and constitute a dietary fibre. The aim of this study was to examine the impact of isomaltooligosaccharides (IMO) as compared to soluble corn fibre (SCF) consumption on blood glucose, insulin and breath hydrogen responses in healthy young men and women. After an overnight fast, nine individuals consumed 25 g of either placebo (PLA), IMO or SCF. Breath hydrogen was significantly higher in the SCF condition than in the IMO and PLA at 90, 120, 150 and 180 min (p < 0.0001). Blood glucose and insulin were higher in the IMO condition (p < 0.0001) at 30 min compared to the SCF or PLA conditions, which were not significantly different from each other. These data suggest that IMO does not constitute a dietary fibre and instead should be explored as a slow-digesting carbohydrate.

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Journal of Insulin Resistance
ISSN: (Online) 2519-7533, (Print) 2412-2785
Page 1 of 6 Original Research
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Authors:
Ryan P. Lowery1,2
Jacob M. Wilson2
Andrew Barninger2
Mahew H. Sharp2
Christopher Irvin2
Mahew Stefan2
William A. Wallace2
Gabriel J. Wilson3
Michael D. Roberts4
Ronald Wagner1
Aliaons:
1Department of Health and
Human Performance,
Concordia University Chicago,
United States
2Applied Science and
Performance Instute,
United States
3Maximum Human
Performance, United States
4Molecular and Applied
Sciences Lab, School of
Kinesiology, Auburn
University, United States
Corresponding author:
Ryan Lowery,
rlowery@theaspi.com
Dates:
Received: 07 Nov. 2017
Accepted: 12 Dec. 2017
Published: 26 Feb. 2018
How to cite this arcle:
Lowery RP, Wilson JM,
Barninger A, et al. The eects
of soluble corn bre and
isomaltooligosacharides on
blood glucose, insulin,
digeson and fermentaon in
healthy young males and
females. J. insul. resist.
2018;3(1), a32. hps://doi.
org/10.4102/jir.v3i1.32
Introducon
Dietary fibres are non-digestible carbohydrates in the diet that, when consumed, pass through the
small intestine into the large intestine where colonic microflora may partially or wholly ferment
them.1,2 While fibre intake is associated with lower body fat and decreased occurrence of diabetes
and heart disease, less than 5% of the United States population meets the standard general
recommendation of 25 g to 30 g daily.2 As a solution to the problem, scientists have attempted to
add novel forms of dietary fibres to various food sources called functional fibres.3 Two popular
sources that have risen in the food and supplement industry are isomaltooligosaccharides (IMO)
and soluble corn fibre (SCF).
Isomaltooligosaccharides primarily derive from exposure of the maltose-rich syrup to the
transglucosidase enzyme4 resulting in an isomaltose-rich syrup, high in digestion-resistant 1,6
alpha bond linkages. In vitro resistance to pancreatic enzyme digestion has led nutrition companies
to list IMO as a fibre.5 However, previous research has demonstrated that isomaltose itself is
almost completely digested (83% or more) by enzymes on the small intestinal border.4,6 Soluble
corn fibre is a newer digestion-resistant substance that still allows for the versatility of IMO in
various food preparations.7 Soluble corn fibre forms first through exposing corn syrup to a suite
of pancreatic and brush border enzymes for 48 h or more, which leaves a stream of sugars and
digestion-resistant carbohydrates.3 This syrup is then filtered repeatedly until the substance is
composed of virtually all non-digestible fibres.8,9
Numerous companies and nutrition products include and list both IMO and SCF as fibre sources.
However, to date, research has not examined the comparison of these two carbohydrates in vivo
in the same setting. Based on the criteria of fibre previously stated, for nutrition products to list
IMO or SCF as a fibre, individuals should experience all of the following criteria succeeding
consumption: (1) a non-significant change in blood glucose, (2) a resultant non-significant change
in blood insulin levels and (3) the demonstration of fermentation via the elevation of the collected
breath hydrogen samples. Given these criteria, the purpose of this study was to investigate the
impact of IMO compared to SCF consumption on blood glucose, insulin and breath hydrogen
responses in healthy young men and women.
Dietary fibre refers to nutrients in the diet that gastrointestinal enzymes do not digest. If properly
labelled, dietary fibres should not significantly elevate blood glucose or insulin and should
ferment in the large intestine. Because of the recent rise in low-carbohydrate products on the
market, consumers use these various fibres without adequate knowledge concerning whether or
not these ingredients affect any blood parameters and constitute a dietary fibre. The aim of this
study was to examine the impact of isomaltooligosaccharides (IMO) as compared to soluble corn
fibre (SCF) consumption on blood glucose, insulin and breath hydrogen responses in healthy
young men and women. After an overnight fast, nine individuals consumed 25 g of either placebo
(PLA), IMO or SCF. Breath hydrogen was significantly higher in the SCF condition than in the
IMO and PLA at 90, 120, 150 and 180 min (p < 0.0001). Blood glucose and insulin were higher in
the IMO condition (p < 0.0001) at 30 min compared to the SCF or PLA conditions, which were not
significantly different from each other. These data suggest that IMO does not constitute a dietary
fibre and instead should be explored as a slow-digesting carbohydrate.
The eects of soluble corn bre and
isomaltooligosacharides on blood glucose, insulin,
digeson and fermentaon in healthy young males
and females
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Copyright: © 2018. The Authors. Licensee: AOSIS. This work is licensed under the Creave Commons Aribuon License.

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Research methods and design
Study design
A randomised, double-blind, crossover study was performed
to assess the impact of IMO as compared to SCF consumption
on blood glucose, insulin and breath hydrogen responses in
healthy young men and women. Subjects reported to the
laboratory on five separate occasions (two familiarisations
and three experimental days). On occasions one and two,
subjects familiarised themselves with the breath hydrogen
testing protocol. On occasions three to five, subjects were
divided randomly into three conditions consisting of a non-
calorie water-based placebo PLA, a bolus of IMO or SCF.
Study populaon and sampling strategy
Ten men and women (aged 27.1 ± 2.7 years, body mass of
81.2 kg ± 4.4 kg, and an average height of 176.7 cm ± 2.8 cm)
in the Tampa Bay, Florida, area were recruited for this
study. No subject had any physical or medical health
complications according to past health examinations, and
all subjects were non-smokers for inclusion in this study.
Participants were required to abstain from consuming any
fibre supplements for one month prior to and during the
washout period. The subjects completed a 12 h, overnight
fast before the morning of the study and were instructed to
avoid high-fibre items (> 5 g per serving) for 24 h before
the experimental conditions. The IntegReview IRB (Austin,
TX) #8100 approved all procedures for the study, which
was carried out at the Applied Science and Performance
Institute.
Intervenon
Randomly-assigned participants consumed a non-calorie
water-based PLA, 25 g of IMO syrup (Tate & Lyle, PLC,
United Kingdom) or 25 g of SCF syrup (Tate & Lyle, PLC,
United Kingdom). Participants consumed both syrups as a
liquid formulation by mixing 25 g of syrup with eight ounces
of water and stirred until the solution was clear. A one-week
washout period existed between experimental conditions.
The identity of the conditions that were given to the
participants remained unknown to both the participants and
the primary researchers for the entire study. These solutions
were labelled as A, B or C and given to the researchers
working directly with the subjects to maintain a double-
blinded method.
Data collecon
Subjects’ blood and breath hydrogen were taken at baseline
and at 30, 60, 90, 120, 150 and 180 min following consumption
of their respective solutions. Next, venous blood was collected
from the antecubital vein using a 21-gauge needle into a
4 mL EDTA tube (BD Vacutainer®, Becton, Dickinson and
Company, Franklin Lakes, NJ) by a certified phlebotomist.
Then, blood was prepped and assayed following the 180-min
experiment for blood glucose and insulin. Finally, breath
hydrogen was gathered in real time using a Gastro+
Gastrolyzer® (coVita LLC, Santa Barbara, CA) according to
the manufacturer’s instructions.
Stascal analysis
Before carrying out the parametric statistical analysis,
dependent variables were examined for a normal distribution
and outliers through investigation of boxplots and a
normality test (e.g. Shapiro Wilk). No outliers were detected
and data pasted normality testing (Table 1). Repeated
measures analysis of variance (ANOVA) were used to
scrutinise the effects of supplementation on dependent
variables assuming group (SCF, IMO and PLA) and time
(0, 30, 60, 90, 120, 150 and 180 min) as fixed factors (GraphPad
Prism 7®, La Jolla, CA). Whenever a significant F-value was
obtained, a post-hoc test with a Tukey’s adjustment was
performed for multiple comparison purposes. The significance
level was previously set at p < 0.05. Results are expressed as
mean ± standard error mean.
Results
Of the 10 subjects, nine completed the trial, while one
withdrew from the study because of nausea associated
with measures taken during baseline testing. Thus, all
data are reported based on the final subject pool. A group
by time interaction was demonstrated for breath hydrogen
response (p < 0.0001) and post-hoc analysis revealed
that SCF was significantly higher than IMO and PLA at
90, 120, 150 and 180 min (Figure 1a and Table 2). No
significant differences occurred throughout the trial
between PLA and IMO for breath hydrogen. A group by
time interaction was demonstrated for blood glucose
response (p < 0.0001) and post-hoc analysis revealed that
IMO was significantly higher than SCF at 30 min (p <
0.0001; Figure 1b and Table 3). There were no significant
differences between SCF and PLA throughout the trial for
blood glucose. A group by time interaction was noted
for insulin (p < 0.0001), whereby IMO was significantly
higher than SCF and PLA at 30 and 60 min (Figure 1c and
Table 4). No significant differences in blood glucose were
detected between SCF and PLA throughout the trial.
In addition, Figures 2, 3 and 4 represent the individual
responses for breath hydrogen, blood glucose and insulin,
respectively.
Discussion
The purpose of this study was to investigate the impact of
IMO as compared to SCF consumption relative to the PLA on
blood glucose, insulin and breath hydrogen responses in
healthy men and women. The primary findings of this study
TABLE 1: Baseline values of dependent variables.
Variable SCF IMO PLA p
Breath hydrogen (ppm) 4 ± 3 4 ± 3 3 ± 3 0.699
Blood glucose (mg/dL) 82 ± 8 83 ± 9 86 ± 9 0.635
Insulin (IU/mL) 3.8 ± 2.3 4.1 ± 2.4 4.0 ± 2.8 0.908
IMO, isomaltooligosaccharides; PLA, placebo; SCF, soluble corn bre.

Page 3 of 6 Original Research
hp://www.insulinresistance.org Open Access
were that SCF did not raise either blood glucose or insulin as
compared to PLA. However, SCF produced a significant rise
in breath hydrogen, indicating that it arrived in the large
intestine intact and was fermented by bacteria. In contrast,
IMO produced a robust rise in blood glucose and insulin
30 min after meal consumption and did not increase breath
hydrogen. Following is a discussion of each of these variables.
Blood glucose and insulin responses
Regulation of blood glucose is highly sought after in our
society. With the resurgence of low-carbohydrate, high-fat,
ketogenic diets, it is essential to identify ingredients that do
not significantly impact blood glucose or insulin. Our
results demonstrated that IMO consumption led to a rise
of nearly 50 mg/dL in blood glucose, with a concomitant
five-fold rise in insulin at 30 min. However, no change was
seen in SCF in either variable. Consequently, these results
agreed with that of Kohmoto et al.4, who found that
IMO were nearly 85% digested. Moreover, Cervantes-Pahm
et al.8 and Kendall et al.9 found virtually no digestion in
SCF, both in vivo and in vitro.
Fermentaon
This study operationalised fermentation through the breath
hydrogen technique. Resting levels of breath hydrogen are
typically below 10 ppm; however, resting values in our study
were approximately 4 ppm in all conditions. Our results
demonstrated no change in the IMO condition relative to the
PLA. Nevertheless, SCF increased to nearly four-fold to
120 min, and remained as such throughout the experiment.
These results agreed with previous research, which
demonstrated no change in breath hydrogen over 180 min
following IMO consumption.10 It is important to note that
two subjects showed no breath hydrogen response, which
had previously been demonstrated to occur in over 15% of
c
30 60 90 120 150 180
0
Time (min)
0
5
10
15
20
25
30
Insulin (uIU/mL)
^
#,
*
# = IMO significantly higher than PLA (p < 0.01)
* = IMO significantly higher than SCF (p < 0.05)
^ = IMO signifcantly higher than SCF and PLA (p < 0.0001)
SCF
IMO
PLA
b
Time (min)
30 60 90 120 150 180
0
60
70
80
90
100
110
120
130
140
150
Blood glucose (mg/d L)
^
030 60 90 120 150 180
0
5
10
15
20
25
Time (min)
Hydrogen (ppm)
^^
^
#,*
a
SCF
IMO
PLA
# = SCF significantly higher than PLA (
p < 0.01)
* = SCF significantly higher than IMO (p < 0.05)
^ = SCF significantly higher than IMO and PLA (p < 0.0001)
^ = IMO significantly higher than SCF
and PLA(p < 0.0001)
SCF
IMO
PLA
FIGURE 1: (a) Group hydrogen responses, (b) glucose group responses (c) insulin
group responses.
TABLE 2: Group breath hydrogen response in parts per million (ppm).
Condion 0 min 30 min 60 min 90 min 120 min 150 min 180 min
SCF 4 ± 1 5 ± 1 7 ± 2 9 ± 3a,b 16 ± 4c17 ± 4c16 ± 4c
IMO 4 ± 1 4 ± 1 2 ± 1 2 ± 1 1 ± 1 2 ± 1 1 ± 0
PLA 3 ± 1 4 ± 1 3 ± 1 3 ± 1 2 ± 1 1 ± 1 0 ± 0
IMO, isomaltooligosaccharides; PLA, placebo; SCF, soluble corn bre.
a SCF signicantly higher than PLA (p < 0.01).
b SCF signicantly higher than IMO (p < 0.05).
c SCF signicantly higher than IMO and PLA (p < 0.0001).
TABLE 3: Group blood glucose response in mg/dL.
Condion 0 min 30 min 60 min 90 min 120 min 150 min 180 min
SCF 82 ± 3 89 ± 4 83 ± 4 84 ± 5 81 ± 4 82 ± 4 82 ± 3
IMO 83 ± 3 132 ± 6a91 ± 6 84 ± 4 85 ± 4 85 ± 4 86 ± 3
PLA 86 ± 3 88 ± 4 86 ± 3 87 ± 4 87 ± 4 85 ± 4 85 ± 3
IMO, isomaltooligosaccharides; PLA, placebo; SCF, soluble corn bre.
a IMO signicantly higher than SCF and PLA (p < 0.0001).
TABLE 4: Group insulin response in μIU/mL.
Condion 0 min 30 min 60 min 90 min 120 min 150 min 180 min
SCF 3.8 ± 0.8 5.4 ± 1.2 4.5 ± 0.9 4.5 ± 0.9 3.5 ± 0.9 3.8 ± 0.8 3.3 ± 0.8
IMO 4.1 ± 0.8 22.0 ± 3.7a9.4 ± 1.1b,c 6.0 ± 0.9 4.3 ± 0.8 3.9 ± 0.5 3.9 ± 0.5
PLA 4.0 ± 0.9 4.2 ± 1.0 4.2 ± 1.0 3.7 ± 0.6 3.4 ± 0.7 3.7 ± 0.7 3.0 ± 0.5
IMO, isomaltooligosaccharides; PLA, placebo; SCF, soluble corn bre.
a IMO signicantly higher than SCF and PLA (p < 0.0001).
b IMO signicantly higher than PLA (p < 0.01).
c IMO signicantly higher than SCF (p < 0.05).

Page 4 of 6 Original Research
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030 60 90 120 150 180
Hydrogen (ppm)
0
10
20
30
40
Time (min)
030 60 90 120 150 180
Hydrogen (ppm)
0
3
6
9
12
15
0
3
6
9
12
15
Time (min)
030 60 90 120 150 180
Hydrogen (ppm)
Time (min)
a b
c
IMO
PLA
SCF
FIGURE 2: Individual breath hydrogen responses to (a) soluble corn bre, (b) isomaltooligosaccharides and (c) placebo.
030 60 90 120 150 180
Blood glucose (mg/dL)
60
70
80
90
110
110
120
60
70
80
90
110
110
120
Time (min)
030 60 90 120 150 180
Blood glucose (mg/dL)
60
70
80
90
100
110
120
140
150
160
Time (min)
030 60 90 120 150 180
Blood glucose (mg/dL)
Time (min)
a b
c
IMO
PLA
SCF
FIGURE 3: Individual blood glucose responses to (a) soluble corn bre, (b) isomaltooligosaccharides and (c) placebo.

Page 5 of 6 Original Research
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the population.11,12 Also, prebiotic activity is indicative of
digestibility. Using inulin as a standard, Oku et al.10 found
very little prebiotic activity with IMO. More specifically,
IMOs were 14 times less effective than inulin. In contrast,
SCF was found to be equal to inulin in prebiotic activity and
three to four times more tolerable.7
Conclusions
Previous research combined with this study’s results
collectively indicate that of the two carbohydrate sources
examined, SCF – but not IMO – can be listed on food labels as
a dietary fibre source. Given its versatility in food preparation,
SCF appears to be a viable option for manufacturers to
produce high-fibre, palatable food-based products that
would support a low-carbohydrate, ketogenic diet.
Acknowledgements
The authors would like to thank Daniel Orrego and Ron
Penna for their thoughtful insights into this study design.
Leftover funds from a project supported by Quest Nutrition
were used to pay for the blood analysis for this study. Quest
Nutrition sells nutritional products that use soluble corn fibre.
Compeng interests
The authors declare that they have no financial or personal
relationships which may have inappropriately influenced
them in writing this article.
Authors’ contribuons
R.P.L. was the project leader. J.M.W assisted with experimental
and project design. A.B., M.H.S., C.I., W.A.L., and M.S
assisted with experimental and project design and helped
with data collection. G.J.W, M.D.R. and R.W. helped oversee
the draft and final version of the manuscript.
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PLA
SCF
0
030 60 90 120 150 180
2
4
6
8
10
12
14
Insulin (uIU/mL)
Time (min)
030 60 90 120 150 180
Insulin (uIU/mL)
0
5
10
15
20
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50
Time (min)
030 60 90 120 150 180
Insulin (uIU/mL)
0
2
4
6
8
10
12
14
Time (min)
a b
c
FIGURE 4: Individual insulin responses to (a) soluble corn bre, (b) isomaltooligosaccharides and (c) placebo.

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