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Vegetarian Nutrition

VN: Therapeutic Vegetarian Diets and Attrition (2009)

Citation:

Kaartinen K, Lammi K, Hypen M, Nenonen M, Hanninen O, Rauma AL. Vegan diet alleviates fibromyalgia symptoms. Scand J Rheumatol. 2000; 29 (5): 308-313.

PubMed ID: 11093597
 
Study Design:
Non-Randomized Controlled Trial
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Negative NEGATIVE: See Quality Criteria Checklist below.
Research Purpose:

To evaluate the effects of this strict vegan ("living food") diet on the symptoms of fibromyalgia.

Inclusion Criteria:

Specific inclusion criteria was not provided. The sample included Finnish females with diagnosed fibromyalgia according to the 1990 American College of Rheumatology criteria.

Exclusion Criteria:

None disclosed.

Description of Study Protocol:
  • Recruitment: Authors did not disclose recruitment information in the article
  • Design: A non-randomized group controlled trial design was used. Participants chose the diet they wanted to follow.
  • Blinding: None.

Intervention

Participants in the intervention group followed a "living food" vegan diet for three months that was characterized by:

  • Approximately 1,829 kcal per day
  • 16% of calories from protein
  • 53% of calories from carbohydrates
  • 31% of calories from fat
  • Zero mg of cholesterol
  • Foods were uncooked and included: Fruits, berries, vegetables, mushrooms, nuts, seeds, legumes and cereals
  • Vitamin B12 supplement.

The authors indicate diet compliance was measured using urine sodium and food records. However, food record data was not reported. An instructor, not specified if he or she was a licensed dietitian, was available to help participants if they had problems with following the diet during the entire study period (i.e., three months). Authors do not indicate how many times, if any, participants requested help with following the diet. Of the 18 participants, four reported consuming fish during the study period.

Statistical Analysis

Statistical significance was set at P<0.05. Repeated measures ANOVA were used to evaluate differences among treatment groups. Baseline differences among groups were done using one-way ANOVA.

Data Collection Summary:

Timing of Measurements

Intervention period was three months. Data were collected at baseline (before intervention period), in the middle of intervention period, two months after the intervention period and five months after the intervention period. Nevertheless, results and data reported are not consistent for all measures. It is unclear if the authors conflated follow-up measures for some variables or if some of measures were not taken during all measurement periods. Below are the variables measured and timing of measurements as reported in the article.
 
Dependent Variables
 
  • Body Mass Index (BMI) measured at baseline, middle of intervention, end of intervention and two months after intervention
  • Biochemical indicators:
    • Serum cholesterol (mmol per L), measured at baseline, one month after intervention started and at the end of the intervention
    • Urine sodium (mmol per L), measured at baseline and one month after intervention started
    • Hematocrit (percentage)
    • Erythrocyte sedimentation rate (ESR).
  • Fibromyalgia symptoms:
    • Pain at rest measured with a standardized questionnaire
    • Quality of sleep measured with a standardized questionnaire
    • Morning stiffness measured with a standardized questionnaire
    • Depression using Beck's Depression Inventory
    • General health using the Health Assessment Questionnaire
    • Hand-grip power measured at baseline, one month after intervention started and at end of intervention using the Martin vigorimeter with standardized positioning and instructions
    • Tender fibromyalgia points measured at baseline, one month after intervention started and at end of intervention.
  • Dietary assessment using five-day food records
  • Use of pain killers (amount of tablets per day)
  • Physical activity using a standardized formula to calculate an exercise index measure at baseline and one month after the intervention started.
Independent Variables
  • Vegan diet "living food"
  • Omnivorous diet.
Control Variables
 
None.
 
Additional Variables
  • Use of medications
  • Duration of disease.

 

Description of Actual Data Sample:

Initial N

Note: It is unclear how the stated total (N=28) relates to the number of subjects in the comparison groups. The text appears inconsistent.

  • N=28 (all females)
  • Intervention group (vegan diet), N=21
  • Control group (omnivorous diet), N=17.

Attrition (Final N)

  • N=25 (all females)
  • Intervention group (vegan diet), N=18
  • Control group (omnivorous diet), N=15. 

Age

Average age (in years):

  • Intervention group, 51
  • Control group, 52.

Ethnicity

Finnish.

Anthropometrics 

BMI (kg/m2):

  • Intervention group, 28
  • Control group, 28.

Location

Finland.

Summary of Results:
  • BMI: There was a significant decrease in BMI at the end of intervention period among those following the vegan diet (P<0.001). Participants discontinued the vegan diet after the intervention period, at which point BMI increased. No actual values of BMI were reported by the authors, only the significance of the difference among intervention and control group groups. 
  • Serum cholesterol: Among participants in the intervention group, serum cholesterol decreased significantly (P=0.003)
  • Exercise index: No significant change among groups was observed
  • Quality of sleep: There was a significant improvement in the quality of sleep among intervention participants (P=0.0001) 
  • Beck's Depression Inventory: No significant difference among the groups during study period (P=0.112)
  • Pain at rest: There was a significant decrease in pain at rest among participants in the intervention group during study period (P=0.005)
  • Health Assessment Questionnaire: There was a significant improvement in general health (P=0.03) among intervention group participants
  • Use of pain killers (amount of tablets per day): There was no significant difference among the groups.
Note: The authors did not report the actual values of the variables in the text other than significance values when a significant difference was observed. Also, there are multiple significance values that do not allow the reader to clearly identify at which point during the study each variable was significantly different. The figures of the results included in the article do not provide the values to assess baseline measures nor the degree of change among those variables that increased or decrease significantly.
Author Conclusion:

A vegan diet alleviates the symptoms of fibromyalgia at least in the short run. Further studies are needed to verify these results and especially in crossover design.

Funding Source:
Other: no funding sources acknowledged
Reviewer Comments:

Although participants who followed a vegan diet, specifically "living food," had a significant decrease in their BMI after three months on the diet compared to those following an omnivorous diet, it is unclear the actual composition of the diet participants followed. Also, no actual values for the measures were provided that could allow the reader to assess the degree of change in BMI or other variables. Figures for the results were also unclear and imprecise. Although the authors indicate they assessed adherence to the vegan diet, these measures were also not reported and four participants reported consuming fish. 

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
  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
  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
  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
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
  1. Was the research question clearly stated? Yes
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.1. 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
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? No
  1.3. Were the target population and setting specified? No
  2. Was the selection of study subjects/patients free from bias? No
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
  2.1. 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? No
  2.2. Were criteria applied equally to all study groups? No
  2.3. Were health, demographics, and other characteristics of subjects described? 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? No
  2.4. Were the subjects/patients a representative sample of the relevant population? No
  3. Were study groups comparable? 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
  3.1. 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
  3.2. 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
  3.3. 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
  3.4. 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
  3.5. 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
  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. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? 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
  4.2. 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
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? No
  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
  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. 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
  5.1. 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.) 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.) No
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  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
  5.4. 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
  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. 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
  6.1. 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
  6.2. 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
  6.3. 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? No
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  6.6. Were extra or unplanned treatments 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
  6.7. 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
  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. 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
  7.1. 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
  7.2. 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
  7.3. 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
  7.4. 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
  7.5. 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
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? 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? No
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.2. Were correct statistical tests used and assumptions of test not violated? 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
  8.3. 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
  8.4. 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
  8.5. 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
  8.6. 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? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
  9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? 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. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes
  10.2. Was the study free from apparent conflict of interest? Yes