DM: Effectiveness of MNT Provided by RD/RDN (2015)


Barakatun Nisak MY, Ruzita AT, Norimah AK, Kamaruddin NA. Medical nutrition therapy administered by a dietitian yields favourable diabetes outcomes in individuals with type 2 diabetes mellitus. Med J Malaysia. 2013; 68(1): 18-23.

PubMed ID: 23466761
Study Design:
Before-After Study
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To evaluate the effect of individualized Medical Nutrition Therapy (MNT) intervention administered by a dietitian in individuals with type 2 diabetes mellitus on glycemic control, metabolic parameters and dietary intake.

Inclusion Criteria:
  • Men or non-pregnant women with poorly controlled type 2 diabetes (fasting glucose less than 15mmol per L and HbA1c less than 12%) who were treated with diet and oral anti-diabetic agents (metformin less than 1,650mg per day or first-generation sulfonylurea such as glibenclamide; 5mg to 15mg per day) on a stable dose over the previous three months
  • Subjects were not using insulin and none of them had clinically significant cardiovascular, renal or liver disease
  • Provided written informed consent.
Exclusion Criteria:
Did not turn up for the subsequent visits.
Description of Study Protocol:


Individuals with type 2 diabetes were recruited for this study.


Before and after study.

Blinding Used

Implied with measurements.


  • Individualized MNT intervention administered by a dietitian
  • Nutrient and energy prescriptions were made according to individualized energy requirements
  • The knowledge assessment questionnaire was based on the content of the counseling session. It was designed to include questions on the importance of dietary aspects to manage diabetes, the role of specific nutrients on blood glucose level and the food myths practices in achieving good glycemic control.

Statistical Analysis

  • Nutrient analyses were performed using a computerized dietary analysis program (Nutritionist Pro Version 2.0; First Data Bank, The Hearst Corp, NY, US)
  • The results were presented as mean daily intake of energy, protein, total carbohydrate, fat, cholesterol, fiber, sodium and calcium
  • An intent to treat analysis was performed on the assumption that subjects adhered to the dietary advice and had baseline and endpoint values of HbA1c values.
Data Collection Summary:

Timing of Measurements

  • All subjects received MNT intervention at baseline and emphasized at week four and week 12
  • Measurements were performed in the morning after the subjects had fasted for at least 10 hours at baseline, week four and week 12 of the study.

Dependent Variables

  • Fasting blood samples were drawn through the antecubital arm vein for glucose, fructosamine, HbA1c, insulin levels and lipid profiles. Serum fasting glucose, plasma fructosamine, HbA1c and plasma lipid components were measured using the COBAS automated analyzer with specific enzymatic assay.
  • Body weight was measured using a digital weighing scale to the nearest 1kg in light clothing with empty pockets and without shoes, watch and other accessories
  • Height was measured with the height attachment on the same weighing scale to the nearest 0.1cm with the subjects wearing no shoes
  • Body weight and height were used to calculate body mass index (BMI)
  • Waist circumference was measured to the nearest 0.1cm at the midway between the lowest rib and the iliac crest
  • Blood pressure was measured with the use of an automatic blood pressure monitor.

Independent Variables

  • Individualized MNT intervention administered by a dietitian
  • Nutrient and energy prescriptions were made according to individualized energy requirements
  • The knowledge assessment questionnaire was based on the content of the counseling session. It was designed to include questions on the importance of dietary aspects to manage diabetes, the role of specific nutrients on blood glucose level and the food myths practices in achieving good glycemic control.
  • Dietary intake assessments were carried out by the primary investigator at baseline (used as the basis for individualized dietary counseling), week four and week 12 of the study using three-day food records. Two weekdays and one weekend day were specified in the record to account for the variation in food intake data.
Description of Actual Data Sample:
  • Initial N: N=150 subjects screened with 104 subjects recruited
  • Attrition (final N): N=100 (63% female 37% male)
  • Age: Mean age 56.4±9.9 years.


  • Malaysian: 53%
  • Chinese: 30%
  • Indian: 15%
  • Other: 2%.

Other Relevant Demographics

  • Single: 8%
  • Married: 74%
  • Widowed or divorced: 18%.


  • Baseline BMI (kg/m2): 26.9±4.8
  • Week 12 BMI: 26.8±4.8
  • Duration of diabetes: 6.5±4.9 years
  • Baseline HbA1c: 7.6±1.2%.




Summary of Results:

Key Findings

  • After 12 weeks of medical nutrition therapy, there was a significant reduction in fasting blood glucose (from 7.18±2.0mmol to 7.52±2.1mmol per L, P<0.05) and HbA1c (from 7.6±1.2% to 7.2±1.1%, P<0.001)
  • After 12 weeks of medical nutrition therapy, there was a significant reduction in waist circumference (from 90.7±10.2cm to 89.1±9.8cm, P<0.05)
  • After 12 weeks of medical nutrition therapy, there was a significant increase in HDL-cholesterol (from 1.1±0.3mmol to 1.2±0.3mmol per L, P<0.05)
  • However, there were no significant changes in total cholesterol, LDL-cholesterol, triglycerides or blood pressure
  • There were no significant changes in fasting insulin levels
  • Dietary intake and nutrition knowledge score (42±19% vs. 75±17%; P<0.001) were significantly improved from the baseline
  • There were no significant changes in body weight or BMI during the trial.
Author Conclusion:

Individualized medical nutrition therapy administered by a dietitian resulted in favorable diabetes outcomes, which were more apparent for individuals with higher than optimal HbA1c levels at the start of the study.

Funding Source:
University/Hospital: Department of Nutrition & Dietetics, Universitit Putra Malaysia
Reviewer Comments:

The authors caution against over-interpretation of the results given the facts that this was a small, non-randomized pre-post design without a control arm. They also noted that there is a high prevalence of dietary intake under-reporting, which can lead to uncertainty in terms of reliability of the dietary data.

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)? Yes
  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? 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? Yes
  10.2. Was the study free from apparent conflict of interest? Yes