VN: Therapeutic Vegetarian Diets and Attrition (2009)

Citation:
 
Study Design:
Class:
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Quality Rating:
Research Purpose:

To examine the effect of ghee (clarified butter) on serum lipid profile after eight weeks.

Inclusion Criteria:

Participants were: 

  • Inmates at an Ashram in India
  • Without medical conditions  
  • Non-smokers
  • Did not consume alcohol
  • Followed a lactovegetarian diet.
Exclusion Criteria:

None disclosed.

Description of Study Protocol:

Recruitment

Participants were recruited from a community in India. The authors did not indicate the method of recruitment within this community.

Design

Randomized controlled trial with a two-week lead-in phase. During the lead-in phase, participants in both groups were asked to follow a vegetarian diet and avoiding products containing ghee while maintaining their usual lifestyle (e.g., physical activity).

Blinding Used

Investigators who analyzed blood samples were blinded with regards to participants' group assignment.

Intervention

Participants were randomly assigned to one of two groups: Group A (experimental) and Group B (control)

  • Group A (experimental) 
    • Followed a lactovegetarian diet 
    • 25% of energy from fats, from which 10% came from ghee (clarified butter).
  • Group B (control)
  • Followed a lactovegetarian diet
    • All visible fat came from mustard oil; no ghee was used
    • Both groups followed the diet for eight weeks and received the ghee or mustard oil in the form of a Potato Curry dish. All participants had their meals at a common kitchen.  

Statistical Analysis

Changes in serum lipid levels were analyzed using repeated measures. Two-way ANOVA was used to examine differences among groups at baseline, at four weeks and eight weeks, when significant differences were observed.

Data Collection Summary:

Timing of Measurements

Participants followed the diet for eight weeks. Measures were taken two weeks before starting intervention (i.e., lead-in phase), at baseline (Week Zero), at four weeks and at the end of the study period (week eight).

Dependent Variables

  • Total cholesterol (mg per dL)
  • Total triacylglycerols (mg per dL)
  • HDL cholesterol (mg per dL)
  • LDL cholesterol (mg per dL)
  • VLDL cholesterol (mg per dL)
  • Total cholesterol: HDL cholesterol ratio
  • Lipoprotein (a) (mg per dL): Measured only at Week Zero and eight weeks.

All lipids were measured and calculated using kits from Randox laboratories.

Independent Variables

Diet intervention (group A vs. group B).

Additional variables

  • Age (years)
  • Weight (kg)
  • Height (cm)
  • BMI (kg/m2)
  • Waist-to-hip ratio.

 Detailed description of how measures were taken were not provided by authors.

Description of Actual Data Sample:
  • Initial N: N=35 (24 males, 11 females)
  • Attrition (final N): N=24 (17 males, 7 females); 31% attrition (authors did not indicate reasons for withdrawals).

Age (Mean±SD)

  • Group A (experimental): 27.09±5.99
  • Group B (control): 26.31±4.81.

Ethnicity

Indians.

Anthropometrics

  • BMI
    • Group A (experimental): 20.58±3.97
    • Group B (control): 20.93±1.51.
  • Waist-to-hip ratio
    • Group A (experimental): 0.83±.06
    • Group B (control): 0.85±.05.

Location

Ashram (closed community) in India, New Delhi.

Summary of Results:

There were no significant changes in any of serum lipid measures at any point during the study among both groups. However, authors did not provide significance values or confidence intervals.  

Variable Group A (Experimental) N=11 Group B (Control) N=13
Baseline 8 Weeks Baseline 8 Weeks
Total Cholesterol (mg per dL) 153.55±35.47 159.55±34.27 146.92±29.54 142.54±31.10
LDL Cholesterol (mg per dL) 95.02±28.85 96.33±35.17 91.18±28.91 82.64±36.69
HDL Cholesterol (mg per dL) 41.64±6.87 54.51±10.89 40.35±9.50 46.38±11.72
Total Cholesterol/HDL ratio 3.70±0.69 3.03±0.75 3.80±0.99 3.30±1.20
VLDL Cholesterol (mg per dL) 16.49±6.49 13.78±4.48 15.42±6.46 13.48±4.95
Triacylglycerides (mg per dL) 82.45±32.45 68.91±22.39 77.08±32.28 65.46±20.17
Lipoprotein (a) (mg per dL) 38.15±19.69 42.07±20.81 25.13±15.02 32.00±15.19

Other Findings

  • Examination of dietary intake during the study indicated that Group A consumed on average 24% of energy from fat while Group B consumed only 20% energy from fat
  • Although it did not reach significance, HDL cholesterol increased at the end of the study period among the experimental group
  • Total serum cholesterol also increased among half (N=6) of the experimental group participants (not statistically significant).
Author Conclusion:

The present study suggests that the adverse opinion about ghee prevalent in the medical community may not be entirely valid. Consuming ghee at the level of 10% of total energy intake in a vegetarian diet generally has no effect on the serum lipid profile of healthy, young, physically active individuals, but a few individuals may respond differently.

Funding Source:
Government: Indian Council of Medical Research
Reviewer Comments:

The study suggests that consumption of clarified butter (ghee), commonly used in India and made of 65% saturated fatty acids (SFA) and 32% monosaturated fatty acids (MUFA), does not raise serum cholesterol and thus does not increase the risk of atherosclerosis. However, participants in the study were not representative of the population; they lived in a community that encourages a yogic lifestyle and principles, they were young, normocholesterolemic and physically active.

Statistical analysis was vague and the authors did not provide level of significance nor statistical values that examined difference among groups based on diet. Diet compliance was not reported although the authors indicate dietary intake was examined and yet no data is provided on actual diet and nutrient composition. It is unclear whether other dietary factors besides the consumption of ghee may have had an effect on serum lipids.

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? Yes
  1.3. Were the target population and setting specified? Yes
  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? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.3. 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) Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  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.) No
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) No
  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? No
4. Was method of handling withdrawals described? No
  4.1. Were follow-up methods described and the same for all groups? No
  4.1. Were follow-up methods described and the same for all groups? No
  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
  4.2. 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? No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? No
  4.4. Were reasons for withdrawals similar across groups? ???
  4.4. Were reasons for withdrawals similar across groups? ???
  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? Yes
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? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? Yes
  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
  5.2. 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
  5.3. 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? No
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? 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? N/A
  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
  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? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  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? No
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  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? No
  8.2. Were correct statistical tests used and assumptions of test not violated? No
  8.3. Were statistics reported with levels of significance and/or confidence intervals? N/A
  8.3. Were statistics reported with levels of significance and/or confidence intervals? N/A
  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? No
  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? 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