DF: Diabetes (2008)


Feldman N, Norenberg C, Voet H, Manor E, Berner Y, Madar Z. Enrichment of an Israeli ethnic food with fibres and their effects on the glycaemic and insulinaemic responses in subjects with non-insulin-dependent diabetes mellitus. Br J Nutr. 1995 Nov; 74 (5): 681-688. PMID: 8541274.

PubMed ID: 8541274
Study Design:
Randomized Crossover Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Negative NEGATIVE: See Quality Criteria Checklist below.
Research Purpose:

Analyze post-prandial responses to melawach foods (made from white flour and fat) containing dietary fiber from locust-bean gum, maize cob or lupin.

Inclusion Criteria:

Non-insulin dependent diabetes mellitus.

Exclusion Criteria:

Not described.

Description of Study Protocol:


Not described.


Randomized, crossover feeding study to a meal containing 18.6 g fiber from locust bean, maize cob or lupin or a control diet (3.6g fiber)


  • Subjects were randomly assigned to take a glucose loading test as well as isocaloric meals containing 18.6 g fiber from locust bean, maize cob or lupin incorporated into melawach.
    • Glucose loading test included 50g glucose
    • Control meal contained basal fiber (3.6g)
    • Two meals contained fiber from locust-bean gum, maize cob or lupin (18.6g)
    • All meals included melawach, margarine, egg and tomato with 12% protein, 35% fat and 53% carbohydrates Meals were adjusted for 50g carbohydrate.
  • Meals were given in random order after a 12-hour fast with seven- to 10-day intervals between meals
  • Blood was collected at baseline (fasting), 30, 60, 120 and 180 minutes post-prandial
    • Plasma glucose
    • Plasma insulin.

Statistical Analysis

  • Multi-parameter analysis and T-test for variables with a "normal" curve
  • Wilcoxon test for paired samples that did not exhibit a "normal" curve
  • P=0.05.
Data Collection Summary:

Timing of Measurements

Blood was collected at baseline (fasting), 30, 60, 120 and 180 minutes post-prandial and analyzed for:

  • Plasma glucose
  • Plasma insulin.

Dependent Variables

  • Plasma glucose
  • Plasma insulin.

Independent Variables

  • Type of added fiber
    • Locust bean
    • Maize cob
    • Lupin.

Control Variables


Description of Actual Data Sample:
  • Initial N: 14 (nine female, five male)
  • Attrition (final N): Not described
  • Age: 38 to 72 years
  • Ethnicity: Not described.

Other Relevant Demographics

  • Fasting plasma glucose: 8.7±4.1mmol per L
  • 11 subjects controlled with oral hypoglycemic agents
  • Three subjects controlled with diet alone.


BMI: 28.8±4.3.


  • Department of Biochemistry and Human Nutrition, Faculty of Agriculture, The Hebrew University, Rehovot, Israel
  • Diabetic Unit, Kupat Holim, Netanya, Israel. 
Summary of Results:


  • Significantly lower glucose following locust bean gum than glucose loading (P<0.001), lupin (P<0.001) and maize cob (P<0.001)
  • The glycemic response (AUC) from locust-bean gum was significantly lower than the other meals in individuals with BMI under 30 (P<0.05), but not BMI over 30
  • Melawach with lupin or maize cob induced similar glucose responses as those from the melawach without fiber
  • Glycemic index of locust bean gum (31%) was significantly lower than lupin (P<0.02), but not maize cob (59%).


  • No significant differences in insulin response by fiber type
  • Insulin response (AUC) lower with locust bean gum in individuals with BMI over 30 (P<0.05).
Author Conclusion:
  • Locust bean's soluble fiber content decreased glucose and insulin levels in NIDDM subjects and may benefit diabetics with a BMI above 30
  • Dietary fiber from maize cob and lupin had no significant effects on glucose and insulin levels.
Funding Source:
University/Hospital: Hebrew University, Kupat Holim
Reviewer Comments:
  • Small sample size
  • No description of how the groups were randomized
  • No description of time between meals or if there was a washout
  • Meals only included one type of food.
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? No
  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? No
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? No
  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.) 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? No
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? No
  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? No
  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? No
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? No
  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? No
  6.6. Were extra or unplanned treatments described? No
  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? Yes
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? No
  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)? No
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  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