DF: Cardiovascular Disease (2008)

Study Design:
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Quality Rating:
Research Purpose:

To examine the impact of fructooligosaccharides on serum acetate, fasting glucose, triacylglycerol and cholesterol levels in men and post-menopausal women with type 2 diabetes.

Inclusion Criteria:
  • Men and post-menopausal women
  • Type 2 diabetes
  • Patients from five medical practices in Nijmegen, Netherlands
  • Fasting blood glucose over 6.5mmol per L
  • Fasting cholesterol over 6.0 mmol per L.
Exclusion Criteria:
  • Gastrointestinal disease
  • Antibiotic treatment or laxative use during three months prior to study.
Description of Study Protocol:


20 patients with type 2 diabetes from five medical practices of general practitioners in Nijmegen, Netherlands.


  • Subjects were randomized to consume either 15g fructooligosaccharides (FOS) or four grams glucose (placebo) for 20 days. They were then crossed over to the alternate therapy with no washout period
  • All subjects received dietary advice aimed at glycemic control
  • Subjects kept a diary of GI tolerance, medication use and lifestyle behaviors
  • Subjecs recorded habitual intake in two-day food diaries during each of the two study periods
  • Fasting levels of the following were measured at Days One, 18, 21, 39 and 42:
    • Blood glucose (by glucometer)
    • Serum lipids
    • Serum acetate.

Blinding Used

Single-blinded (not described).


  • Subjects were randomly assigned to receive 15g FOD vs. four grams glucose (placebo), provided in yogurt split into two doses (breakfast and dinner)
  • Doses of FOS were introduced gradually during the first three days in five-gram increments
  • Subjects were instructed to maintain eating and drinking habits and asked not to consume any probiotic supplements.

Statistical Analysis:

  • Analysis of variance, including patient and treatment (period added with no significant differences)
  • Paired T-tests
  • SDs of effects calculated.
Data Collection Summary:

Timing of Measurements

The following were measured Days One, 18 and 21 (Period One) and Days 39 and 42 (Period Two):

  • Fasting blood glucose
  • Lipids
  • Acetate.

Dependent Variables

  • Blood glucose
  • Serum lipids (total cholesterol, LDL, HDL, triacylglycerol, FFA)
  • Serum acetate.

Independent Variables

  •  Fructooligosaccharides (15g)

Control Variables

  • Sex
  • Physical activity
  • Medications
  • Food, drinking, lifestyle behavior.
Description of Actual Data Sample:
  • Initial N: 20 (nine males, 11 post-menopausal females)
  • Attrition (final N): 20 (100%)
  • Age: 56±5.2 (men); 62±4.1 (women)
  • Ethnicity: Dutch.

Other Relevant Demographics

  • No significant differeneces in BMI, body weight, energy, fiber or macronutrient intake
  • 17 subjects used oral hypoglycemic agents.


BMI: 29.4±4.22 (men) and 27.4±2.72 (women)


Nijmegen, Netherlands.

Summary of Results:

Dietary Intake







Carbohydrate (%)



Fiber (g/MJ)




  • No significant difference between groups
    • TC (95% CI: -0.07, 0.48)
    • HDL-C (-0.04, 0.04)
    • LDL-C (-0.06, 0.34)
    • TG (-0.21, 0.44)
    • FFA (-0.08, 0.04).
  • Eight patients had higher TC after placebo than after fructooligosaccharide
  • 11 patients had lower TC after placebo than after fructooligosaccharide 
  • One patient showed no difference.


  • No significant difference between groups
    • BG (-0.37, 0.40).
  • 11 patients had higher glucose levels after placebo than after fructooligosaccharide
  • Eight patients had lower glucose levels after placebo than after fructooligosaccharide
  • One patient had no difference.


  • No significant difference between groups
    • Serum acetate- (-0.01, 0.01).

Other Findings

  • GI complaints higher in FOS group (P=0.008)
  • No differences found between men and women by treatment
  • Baseline lipid levels lower than expected.
Author Conclusion:

Fructooligosaccharides supplementation for 20 days did not have significant effects on blood glucose and lipid levels in patients with type 2 diabetes under strict medical control.

Funding Source:
Government: Netherlands Ministry for Agriculture, Nature Management and Fishery,
AVEBE (Netherlands), Nutreco, ORAFTI (Belgium)
Food Company:
Reviewer Comments:
  • Small sample size
  • No washout period
  • Glucose measured by glucometer.
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? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  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? N/A
  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? N/A
  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? Yes
  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? No
  8.7. If negative findings, was a power calculation reported to address type 2 error? Yes
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? No
  10.2. Was the study free from apparent conflict of interest? Yes