DM: Glycemic Index (2014)


Holub I, Gostner A, Hessdorfer S, Theis S, Bender G, Willinger B, Schauber J, Melcher R, Allolio B, Scheppach W. Improved metabolic control after 12-week dietary intervention with low glycaemic isomalt in patients with type 2 diabetes mellitus. Horm Metab Res 2009;41(12):886-92.

PubMed ID: 19701877
Study Design:
Time Study
C - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
  • The purpose of this study was to look at possible effects of isomalt on metabolic parameters in patients with type 2 diabetes
  • The primary end-points examined were the effects on HbA1c and blood glucose control
  • Secondary targets were to study the effects on risk parameters for secondary complications or disorders of diabetes in particular cardiovascular disease (CVD).
Inclusion Criteria:
  • Age: More than 18 years
  • BMI: 25kg to 40kg/m2
  • Diabetes treatment with diet alone or metformin or thiazolidindiones without changes in the therapy regimen for at least three months prior to study start
  • HbA1c: 7% to 9% and intake of 30g to 60g per day sucrose or sucrose equivalent from sweetened foods
  • Provided written informed consent
  • Type 2 diabetes.
Exclusion Criteria:
  • Treatment with insulin or any oral anti-diabetic drug other than stable doses of metformin and thiazolidindiones
  • History of severe chronic disease, pregnancy, antibiotics intake within last six weeks prior to entry
  • Glucocorticoid therapy, abnormal dietary habits and dislike of sweetened foods.
Description of Study Protocol:
  • Recruitment: A total of 33 patients with type 2 diabetes were recruited
  • Design: Time series
  • Blinding used: Implied with measurements.


  • Participants received various sweet test products (jam, biscuits, chocolate, etc.) containing 30g isomalt per day instead of higher glycemic carbohydrates. Isomalt doses were increased slowly from five grams per day to 30g per day in the first week.
  • Subjects maintained their usual diet during treatment but were instructed to refrain from additional sweetened foods or diabetic products.

Statistical Analysis

  • Analysis was carried out using SPSS for Windows version 14.0.1
  • Values are provided as means with their standard deviation
  • The non-parametric Friedman test for paired data was performed to test for any significant differences between baseline, six-week and 12-week (end-point) measurements
  • When significant, the non-parametric Wilcoxon rank-sum test for paired data was used to determine the specific differences between means
  • Differences were considered to be significant at P<0.05.
Data Collection Summary:

Timing of Measurements

  • Every night, study participants visited the clinic to collect isomalt products, determine body weights and record subjective gastrointestinal parameters, stool frequency and stool consistency
  • Other measurements made at six weeks and 12 weeks.

Dependent Variables

  • Effects on HbA1c and blood glucose control: HbA1c measurement was performed by HPLC and fructosamine was determined using an enzymatic colorimetric assay kit. Venous blood glucose samples were analyzed by hexokinase methods. Proinsulin concentration was determined using a RIA kit.
  • Serum insulin and C-peptide were measured by RIA and the homeostasis model assessment for insulin resistance (HOMA-IR) was determined for each individual
  • Cholesterol, triacylglycerol (TAG), HDL-cholesterol and LDL-cholesterol in serum were analyzed using colorimetric enzyme kits
  • Oxidised LDL was determined in plasma samples using an ELISA kit and NEFA level was determined by enzymatic colorimetric assay
  • Adiponectin and leptin levels were measured using an RIA kit
  • CRP levels were measured immuno-turbidimetrically and uric acid was determined using colorimetric enzyme test
  • Plasminogen activator inhibitor-1 and tissue plasminogen activator (tPA) were stored at -80° until further analysis
  • Abdominal distension, flatulence, abdominal pain and nausea were scored on semi-quantitative scales from zero (absent) to three (severe). Stool consistency was also scored from one (hard) to four (watery).

Independent Variables

  • Participants received various sweet test products (jam, biscuits, chocolate, etc.) containing 30g isomalt per day instead of higher glycemic carbohydrates. Isomalt doses were increased slowly from five grams per day to 30g per day in the first week.
  • Subjects maintained their usual diet during treatment but were instructed to refrain from additional sweetened foods or diabetic products
  • To assess nutrient intake, a three-day dietary record (two weekdays and one weekend day) was performed before and once a month during the test period
  • Macronutrient intake was calculated with Prodi expert 4.5 software.
Description of Actual Data Sample:
  • Initial N: 33 subjects
  • Attrition (final N): 31 subjects (18 men, 13 women)
  • Age: Mean, 56.1±8.1
  • Ethnicity: Not reported
  • Other relevant demographics: Mean duration of diabetes 6.4±4.9 years
  • Anthropometrics: Mean BMI for men, 33.1±4.9kg/m2; for women, 34.5±4.3kg/m2
  • Location: Germany.


Summary of Results:

Key Findings

  • The treatment resulted in a 13% reduction in GL but had no significant effects on energy, carbohydrates, fat, protein and dietary fiber intake
  • The mean difference in HbA1c from baseline to end-point after 12-week isomalt intake was -0.3±0.5% and this reduction was significant (P=0.004)
  • A significant lowering was observed for serum fructosamine concentration following regular isomalt consumption (P=0.003)
  • After 12 weeks, significant reductions were also observed for fasting blood glucose (change of -0.8±1.9mmol per L, P=0.023) and insulin (change of -70.7±88.0pmol per L, P<0.001)
  • Insulin resistance (HOMA-IR) was also significantly improved during isomalt intervention (P<0.001)
  • Triacylglycerol levels were elevated above normal levels at baseline and showed a significant decrease in the entire study population after six weeks of isomalt intervention (P=0.005), followed by a slow increase from Week Six to Week 12
  • Mean serum cholesterol, LDL-cholesterol and HDL-cholesterol were within the normal range at entry and at the end of the study, demonstrating no significant effect of regular isomalt intake
  • Stool frequency was reported as 1.3±0.6 per day at baseline and showed no differences during the 12-week isomalt intervention (1.4±0.6;P>0.05)
  • There was a slight but statistically significant decrease in body weight of 1.3% during the study period (P=0.004). The mean body weight at baseline of 97.7±17.6kg was reduced by 1.3kg in the entire study population after the 12-week isomalt intake.
Author Conclusion:

The exchange of glycemic ingredients by isomalt and the accomplished reduction of the GL within an otherwise unchanged usual diet leads to an improvement in the metabolic control of patients with type 2 diabetes.

Funding Source:
Other: Sudzucker AG Mannheim/Ochsenfurt, Germany
Reviewer Comments:
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? No
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? Yes
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? No
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes