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Vegetarian Nutrition

VN: Therapeutic Vegetarian Diets and Attrition (2009)

Citation:
Burke LE, Hudson AG, Warziski MT, Styn MA, Music E, Elci OU, Sereika SM. Effects of a vegetarian diet and treatment preference on biochemical and dietary variables in overweight and obese adults: a randomized clinical trial. Am J Clin Nutr. 2007 Sep; 86 (3): 588-596.
PubMed ID: 17823421
 
Study Design:
Randomized clinical trial.
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
  • The purpose was to determine independent and combined effects of treatment preference and a standard behavioral treatment program with a calorie- and fat-restricted ovolactovegetarian diet (LOV-D) compared with a calorie and fat-restricted standard omnivorous weight loss diet (STD-D) on weight, serum lipids, insulin resistance and macronutrient intake in overweight and obese adults
  • To examine whether the above outcomes differed among those who adhered to the vegetarian diet compared to those who did not.

 

Inclusion Criteria:
  • Age between 18 and 55 years
  • Body mass index (BMI) of 27kg/m2 to 43kg/m2
  • Willingness to be randomly assigned to one of two treatment preference conditions and one of two dietary conditions
  • Successful completion of a five-day food diary
  • Willingness and ability to provide informed consent
  • No current medical condition requiring physician supervision of diet or physical activity
  • No physical limitation restricting exercise ability
  • Not pregnant or planning to become pregnant during 18 months of study
  • No current treatment with a medication that might affect weight
  • Alcohol intake not exceeding four drinks per day
  • No participation in a weight-loss program or use of a weight-loss medication within six months before study enrollment
  • Reported consumption of meat, poultry or fish in the past month.
Exclusion Criteria:
  • Participants were ineligible if they did not meet the inclusion criteria above
  • Participants were disqualified if they selected an equal preference for two dietary options
  • Fasting plasma glucose concentration was used to screen for exclusion criterion of diabetes.
Description of Study Protocol:

Recruitment 

Mode of recruitment included mass mailings from purchased lists; a database of persons seeking weight-loss treatment; and telephone announcements to staff, students and faculty at the University of Pittsburgh and University of Pittsburgh Medical Center. 

Design

  • Randomized clinical trial
  • Two-times-two factorial experimental design was used, which resulted in four group assignments:
    • Preference: Yes + LOV-D
    • Preference: Yes + STD-D
    • Preference: No + LOV-D
    • Preference: No + STD-D.  

Blinding Used

  • Staff entering dietary intake data were blinded to the treatment group and assessment period
  • Personnel taking the blood samples were blinded to treatment group.

Intervention

  • Dietary intervention: For participants weighing less than 90.5kg at baseline a diet of 1,200kcal per day was prescribed for women and 1,500kcal per day for men. For those weighing more than 90.5kg at baseline, a diet of 1,500kcal per day for women and 1,800kcal per day for men was prescribed. Participants were also encouraged to reduce fat intake to 25% of total energy.
  • Physical Activity: Participants were encouraged to engage in at least 50 minutes of physical activity per week with gradual increases to at least 150 minutes per week by week six of the study and thereafter
  • Group sessions: Which focused on modifying eating and physical activity behaviors, as well as food tastings and skill-building exercises, were undertaken as follows: Weekly for the first six months; biweekly session for months seven through nine; and monthly for months 10 through 12. Sessions were held separately for the two dietary treatment groups.
  • Diaries: For dietary and physical activities were completed and by participants and submitted at treatment sessions. 

Statistical Analysis

  • ANOVA, Kruskal-Wallis test, chi-square analyses, Fisher's Exact tests were used to compare preference groups and diet groups with participants' characteristics and response variables at baseline
  • Exploratory data analysis methods
  • Full factorial with PROC mixed models used to express change from to baseline for variables such as TG, cholesterol and weight
  • Wilcoxon signed-rank test was used for change in physical activity over time
  • Sobel test used to examine the potential mediation effects of physical activity on biochemical outcomes.
Data Collection Summary:

Timing of Measurements

Baseline and at six-, 12- and 18-month intervals.

Dependent Variables

  • Anthropometrics: BMI (weight in kilograms; measured at baseline and repeated every six months until the final 18-month visit). Weight was obtained after an overnight fast in light clothing, without shoes. Equipment used was the Tanita bioelectrical impedance scale. Height was measured using a wall-mounted stadiometer.
  • Biochemical measurements: Total cholesterol, HDL, LDLTG, serum glucose and insulin concentrations were measured from blood drawn after a 12-hour overnight fast. Glucose concentrations were measured using hexokinase-glucose-6-phosphate dehydrogenase enzymatic assay; insulin measured by radioimmunoassay kit; total, cholesterol, HDL-cholesterol and triacylglycerols were measured enzymatically on an Abbott Super System auto analyzer; LDL-cholesterol was estimated using Friedewald equation for participants with TG concentrations less than 400mg per dL, but automated spectrophotometric assay was used for participants whose TG concentrations were more than 400mg per dL 
  • HOMR-IR  was calculated as fasting insulin concentration.

Independent Variables

  • Diet: Two calorie- and fat-restricted dietary options based on preference. Group one was the standard diet (STD-D) and group two the ovolactovegetarian diet (LOV-D). Each option had two groups (Yes and No). Diets were collected via food records and analyzed using a nutrition data system software.
  • Energy expenditure during physical activity for periods of seven days were measured using Paffenbarger Activity Questionnaire from self-reported data.
Description of Actual Data Sample:

Initial N

  • 200 participants attended baseline assessment; nine were ineligible, 15 were discarded. A total of 176 were assigned to four groups.
  • 86.93% females; N=153 and N=23 males.

Attrition (Final N)

N=132; 75% of participants completed the 18-month assessment.

Age

Mean age, 43.3±9.0 years to 44.9±8.5 years.

Ethnicity

70.5% white; no other ethnic categories were reported.

Other Relevant Demographics

  • Employment: 93.18%
  • Marital status: 63.06% married or lived with a partner.

Anthropometrics

  • Baseline weights: 67.62kg to 136.28kg
  • Mean BMI: 34.02±4.09.

Location

University of Pittsburgh and Pittsburgh Medical Center, Pittsburgh, Pennsylvania, US.

Summary of Results:

Nutrient
Preference Yes STD-D
N=48
Preference Yes
LOV-D
N=35
Preference No STD-D
N=48
Preference No LOV-D
N=45
Energy (MJ or kcal)
Baseline
1,941.3±620.9
2,110.6±784.5
2,155.7±674.8
1,982.7±602.1
Six months
1,482.4±614.6
1,601.2±626.4
1,576.8±560.4
1,396.4±316.1
12 months
1,570.1±646.0
1,592.3±450.2
1,562.4±570.0
1,434.1±380.0
18 months
1,581.6±630.7
1,668.4±524.0
1,567.8±524.3
1,471.1±361.7
Percentage change from baseline (significant within group comparison)
-15.9±28.3 (P<0.01)
-13.9±32.4 (P<0.05)
-22.9±28.5 (P<0.01)
-22.9±18.6
(P<0.01)
Fat (g) Baseline
75.9±31.3
83.3±36.0
87.3±34.6
78.6±31.2
Six months
45.9±32.3
47.5±31.5
50.3±26.2
41.4±20.9
12 months
52.1±36.8
51.1±25.0
51.0±26.1
45.3±21.5
18 months
54.6±33.8
57.6±27.2
52.6±23.9
46.3±21.4
Percentage change from baseline (significant within group comparison)
-23.3±49.8
(P<0.01)
-18.0±52.8
(P<0.01)
-31.5±43.9
(P<0.01)
-36.6±27.1
(P<0.01)
Saturated Fat (g)
Baseline
25.5±11.7
28.6±13.7
29.6±12.1
27.5±13.1
Six months
14.9±11.4
15.4±10.5
17.1±10.1
13.6±9.1
12 months
17.2±12.6
17.1±8.3
17.3±10.4
15.3±9.2
18 months
18.2±11.7
19.5±8.4
17.9±9.3
15.9±9.5
Percentage change from baseline (significant within group comparison)
-23.6±48.7
(P<0.01)
-15.2±57.7
NS
-33.7±34.8
(P<0.01)
-37.5±29.2
(P<0.01)
Mono-unsaturated Fat (g) Baseline
28.9±12.9
31.3±13.5
32.7±12.6
29.1±12.3
Six months
17.4±13.1
17.5±13.1
18.1±9.7
14.5±7.8
12 months
19.7±14.0
18.9±10.4
18.5±10.1
16.2±7.8
18 months
20.4±13.4
21.3±11.2
19.8±10.3
15.9±7.4
Percentage change from baseline (significant within group comparison)
-23.9±53.8
(P<0.01)
-20.2±50.9
(P<0.05)
-31.0±50.0
(P<0.01)
39.9±29.3
(P<0.01)
Poly-unsaturated Fat (g)
Baseline
15.5±6.5
16.8±8.0
18.2±9.6
15.8±6.5
Six months
9.8±6.6
10.8±6.5
11.0±5.6
9.9±4.8
12 months
11.0±9.1
11.4±5.4
10.7±5.4
10.2±4.8
18 months
11.7±7.4
12.5±6.5
10.7±5.0
10.9±5.2
Percentage change from baseline (significant within group comparison)
-17.1±58.6
(P<0.05)
-7.7±71.8
NS
-23.9±70.8
(P<0.05)
-24.0±40.7
(P<0.01)

Diet Adherence

  • Two levels of adherence to the ovolactovegetarian diet (LOV-D) were used: 100% adherence or less than 100% adherence
  • At six, 12 and 18 months, 61%, 53% and 36% reported complete adherence (100%) to the LOV-D, respectively
  • A significant main effect for adherence was found for total cholesterol (P=0.04) and HOMA-IR (P<0.01) at six months, but no significance for those variables were seen at 12 and 18 months
  • Participants who adhered to the LOV-D had lower intake of energy (P<0.01), total fats (P<0.01) and monounsaturated fats (P<0.01) at six months than individuals who reported intakes of meat, poultry or fish. The differences for total fats were marginal at 18 months (P=0.05), but remained significant for monounsaturated fats at 18 months (P=0.02).
Variables
STD-D Preference Yes
LOV-D Preference Yes
STD-D Preference No
LOV-D Preference No
Signif-icance of Diet Effect
Blood Lipids Total Cholesterol (mg per dL)
Baseline
207.9±44.1
231.5±40.5
199.5±29.8
197.2±41.8
NS
Six months
202.8±43.4
207.5±37.0
198.9±37.3
187.4±39.0
12 months
202.6±43.3
209.5±35.2
199.1±36.3
190.3±37.4
18 months
203.8±43.0
212.3±34.8
203.7±30.8
195.8±42.4
Percentage change from baseline (significant within group comparison)
-1.4±10.4
NS
-1.0±16.5
NS
2.5±10.1
NS
-0.1±12.3
NS
LDL:HDL Cholesterol Baseline
2.5±1.0
2.8±1.1
2.3±0.8
2.4±0.9
NS
Six months
2.6±1.1
2.7±0.9
2.5±1.0
2.3±0.8
12 months
2.5±1.0
2.6±0.8
2.3±1.0
2.3±0.9
18 months
2.5±1.1
2.7±0.9
2.3±1.0
2.3±0.9
Percentage change from baseline (significant within group comparison)
4.9±33.9
NS
-1.2±26.2
NS
3.4±20.2
NS
-1.8±23.1
NS
Triacyl-glycerol (mg per dL) Baseline
139.2±86.2
129.2±63.5
132.0±66.9
134.3±63.7
NS
Six months
116±55.8
127.2±57.9
125.1±63.5
124.9±56.4
12 months
126.8±65.1
129.9±57.6
119.2±57.7
118.6±52.0
18 months
126.8±60.8
129.2±65.6
117.2±58.6
119.8±55.5
Percentage change from baseline (significant within group comparison)
1.0±36.5
NS
8.6±54.3
NS
-6.7±24.4
NS
-5.5±32.6
NS
Body Comp-osition Weight (kg)
Baseline
97.9±13.5
97.7±11.5
93.7±16.6
93.0±16.2
NS
Six months
91.5±13.6
89.9±13.9
86.4±17.6
85.7±17.0
12 months
92.6±13.9
90.7±14.2
86.1±17.5
85.1±17.2
18 months
94.6±14.2
93.7±13.4
87.6±17.3
87.1±16.8
Percentage change from baseline (significant within group comparison)
-3.9±6.1
(P<0.01)
-5.3±6.2
(P<0.01)
-8.0±7.8
(P<0.01)
-7.9±8.1
(P<0.01)
Diabetes-related Variables HOMA-IR Baseline
4.4±2.0
4.4±2.0
4.4±2.8
4.6±2.3
NS
Six months
3.7±1.7
3.4±1.7
3.5±2.3
3.6±1.8
12 months
3.8±1.9
3.8±1.5
3.6±2.3
3.7±2.2
18 months
4.1±2.1
3.7±1.6
3.6±2.4
4.1±2.8
Percentage change from baseline (significant within group comparison)
-1.0±38.6
NS
-11.3±34.8
NS
-10.8±32.7
(P<0.05)
-6.1±41.6
NS

Other Findings

  • Average amount of energy expenditure reported at baseline (median reported)
    • Preference Yes+STD-D: 1,556.00kcal
    • Preference Yes+LOV-D: 1,344.00kcal
    • Preference No+STD-D: 1,432.50kcal
    • Preference No+LOV-D: 954.00kcal.
  • At 18 months, the self-reported energy expenditure increased
    • Preference Yes+STD-D, 2,214.50kcal
    • Preference Yes+LOV-D, 1,904.00kcal
    • Preference No+STD-D, 2,222.50kcal
    • Preference No+LOV-D, 2,323.00kcal
    • No significant differences across groups (P=0.52).
  • Physical activity was found to have a direct effect on weight change (P=0.01)
  • Physical activity had a total effect (P<0.01) on total cholesterol values (controlling for weight change). Observations were made at zero to 12 months.
  • Physical activity had a direct effect on total cholesterol (P=0.02). Observations were made at zero to 12 months.
  • Physical activity had a total and direct effect (P<0.01) on HOMA-IR at six months only
  • The effect of physical activity on LDL:HDL cholesterol and TG was mediated through weight loss.
Author Conclusion:
  • Findings did not show that adopting a LOV-D results in significantly improved biochemical measures or dietary patterns than does STD-D, maybe due to the fact that the LOV-D group did not strictly adhere the prescribed diet overtime
  • All participants reduced their total energy and fat consumption and increased physical activity
  • Based on previously reported data, the data suggest the LOV-D led to substantial short-term cardiovascular health benefits. (Data was not included in this article.)
  • Compliance to LOV-D was a challenge over time, which declined to 36% by the 18th month; therefore, findings suggest that strategies are needed to improve long-term adherence to the LOV-D plan so as to achieve the true effects of the intervention and clinical outcomes
  • Study results refute the notion that allowing participants to choose treatment results in favorable outcomes
  • Providing a study participant his or her preferred choice of treatment does not necessarily lead to improved adherence or improved outcomes
  • Limitations include declining compliance to the LOV-D diet over time, thereby limiting the authors' ability to detect differences between the dietary groups; three-day food record may not represent dietary intake throughout the study; under-reporting of energy and fat intakes may be common; underrepresentation of men is also a limitation
  • Neither a LOV-D nor treatment preference, individually or in combination, resulted in significant effects on total cholesterol, LDL:HDL cholesterol, HOMA-IR, or energy and macronutrient consumption in the study population
  • Results should be interpreted with consideration of the declining adherence in abstaining from meat, poultry and fish in the LOV-D group by the 18-month assessment
  • Overall, participants benefited from their participation with improvements in dietary and physical activity measures that were reflected in improved body weight.
Funding Source:
Government: NIH (NIDDK #R01-DK58631); (NIH-NIR#P30-NR03924); NIH-NIDDK #DK-046204; and NIH-NCRR-GCRC#5MO1-RR00056
Reviewer Comments:
  • Strengths: Randomized clinical trial; accounted for dropouts by using intention to treat analyses
  • Concerns: Sample sizes, especially for the vegetarian group, declined to the point where it affected effect size and consequently generalizability
  • Other relevant data such as changes in BMI over time and waist circumferences were mentioned but data were not shown
  • Other macronutrients data such as protein and carbohydrate were not provided as part of the analysis. This is crucial in interpreting the results of weight loss. It is difficult, therefore, to say what proportion of the diet was carbohydrate or protein or the source of protein for the LOV-D groups.
  • Study's outcome will be greatly improved if diet prescription was more tightly controlled; a three-day diet record, in my mind, may affect reported outcomes.
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? 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
  2.1. 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
  2.2. 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.) 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? 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
  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.) 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? 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? 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
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  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? ???
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  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? 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
  8.1. 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
  8.2. 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)? 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
  8.5. 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
  8.6. 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
  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. 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