VN: Types and Diversity of Vegetarian Diets (2009)
The study aimed to answer three questions:
- At what age does growth faltering in height occur in children fed macrobiotic diets?
- Which nutritional factors are associated with linear growth retardation?
- What is the effect of modification of the diet on linear growth?
- Younger than eight years of age
- Dutch and Caucasian
- Birth weight of at least 2,500g
- Gestational age of 38 weeks or more
- No congenital disease
- Consumed macrobiotic diet from birth onward.
- Older than eight years of age
- Not Dutch or Caucasian
- Birth weight less than 2,500g
- Gestational age fewer than 38 weeks
- History of congenital disease
- Did not consumed macrobiotic diet from birth.
Recruitment
- Macrobiotic children: Recruited through macrobiotic teachers and other macrobiotic families participating in the study
- Omnivorous children: Recruited through eight child health clinics throughout the Netherlands.
Design
To identify age groups most at risk for growth faltering, a cross-sectional anthropometric study was done with the Dutch macrobiotic child population age zero to eight years. Anthropometric measurements included: weight, recumbent length (for children younger than two years of age), standing height (for children two years of age and older) and mid-upper arm circumference. Food habits were checked by means of a structured questionnaire, including foods and cooking styles that were either typical or atypical for the macrobiotic diet.
Based on the results of the cross-sectional study, the following recommendations were given to all macrobiotic families in the Netherlands:
- Add fat as an additional source of energy to reach a total of 25% to 30% of energy as fat. Suggestions were made to increase consumption of oil, nuts and seeds.
- Include two to three servings of fish per week (especially fatty fish in the winter)
- Increase consumption of plant sources of vitamin B2 and calcium. (Even though plants are poor sources of calcium, dairy was not explicitly mentioned because this is incompatible with macrobiotic philosophy.)
A mixed-longitudinal study was done with macrobiotic infants (age four to 18 months) and omnivorous control subjects matched for month of birth, sex, parity, educational level of the father and the residential area. Three cohorts of infants were monitored from four to 10 months, eight to 14 months and 12 to 18 months. Weight and recumbent length were measured at two monthly intervals. Two food record periods of three days each were included in the study design, just before or after the second and third anthropometric visit. A single blood sample was collected within three months of completing the six-month longitudinal study.
Based on the findings of the mixed-longitudinal study, dietary recommendations were given to all macrobiotic families. Five to six months later, the initial cross-sectional anthropometric study was repeated in the same macrobiotic population (children now age two to 10 years). Food habits and anthropometric measurements were obtained.
Statistical Analysis
Standard deviation scores were calculated from the median and standard deviation of the Dutch reference data. Student's T-test was used to compare the means of two independent samples. Longitudinal changes in standard deviation scores were tested by paired T-test. In the mixed-longitudinal study, successive measurements in all cohorts were simultaneously compared by multivariate analysis of variance. Multiple regression models were fitted to determine the independent effects of different variables on birth weight, weight gain, linear growth and the presence of skin and muscle wasting and rickets after adjustment for confounding variables.
Timing of Measurements
- Cross-sectional study: Initial anthropometric measurements taken and food habits assessed
- Mixed-longitudinal study: Anthropometric measurements taken at two monthly intervals. Two three-day food journals were taken just before or after the second and third anthropometric visit. A single blood sample was taken within three months of completing the six-month longitudinal study.
- Two-year follow up: The same macrobiotic population underwent similar anthropometric measurements five to six months after they received dietary recommendations from the investigators.
Dependent Variables
- Nutrient composition of diet
- Birth weight and growth of infants and children.
Independent Variable
Macrobiotic diet.
Initial N
- Cross-sectional study: 243 children
- Mixed-longitudinal study: macrobiotic, n = 53; omnivorous, n = 57
- Two-year follow up: n = 194.
Age: Zero to eight years of age
Ethnicity: Dutch
Location: Netherlands.
Macrobiotic diet in Dutch children
- Vegan-like diet consisting of grains (primarily rice), vegetables, pulses and sea vegetables
- Only small amounts of cooked fruits
- Fish on rare occasions
- Meat and dairy products are avoided
- Vitamin D supplements are not used.
The Dutch macrobiotic diet has characteristics similar to diets common in developing countries (high-starch and high-fiber, low-protein).
CROSS SECTIONAL STUDY IN ZERO- TO EIGHT-YEAR-OLD CHILDREN
Birth weight: 4.3% of macrobiotic children had reported birth weights less than 2,500g compared with 2% in a comparable Dutch population (P<0.02). Macrobiotic infant birth weight was significantly less than the Dutch median regardless of sex (P<0.001). A small but significant intrauterine growth retardation was indicated by a lower birth weight of macrobiotic infants.
Growth: Height-for-age of macrobiotic infants followed the median of the standard until the age of six months to eight months, after which a marked decrease was observed, reaching a minimum level between one and a half years and two years. No catch-up growth was observed at older ages. The curve of weight-for-age showed the same pattern, but a partial return to the median of the reference was observed after two years of age. The curve of weight for height followed the median Dutch reference.
Relation to diet: Standard deviation scores of weight, height and arm circumference were significantly higher in children from families consuming dairy products at least three times per week compared with children from families who rarely or never used dairy products. No association was observed between standard deviation scores and family consumption of fish, meat or eggs.
MIXED-LONGITUDINAL STUDY IN FOUR-MONTH TO 18-MONTH-OLD INFANTS
Weaning diet: Macrobiotic mothers continued to breastfeed for an average of 13.6 months vs. the control group average of 6.6 months.
Intake of Energy and Nutrients by Infants (6-16 months of age) on Macrobiotic and Omnivorous Diets
|
Macrobiotic Group (n=49) Mean±Standard Deviatoin |
Control Group (n=57) Mean±Standard Deviation |
Statistical Significance of Group Difference |
Animal Protein (grams) |
4±3 | 24±8 |
P<0.001 |
Total Protein (grams) | 20±7 | 32±10 | P<0.001 |
Fat (grams) | 22±9 | 30±7 | P<0.001 |
Calcium (milligrams) | 280±68 | 751±230 | P<0.001 |
Riboflavin (milligrams) | 0.4±0.1 | 1.1±0.3 | P<0.001 |
Iron (milligrams) | 5.1±2.8 | 4±1.6 | P<0.001 |
Vitamin C (milligrams) | 53±22 | 77±40 | P<0.001 |
Vitamin B12 (milligrams) |
0.3±0.2 |
2.9±1.3 |
P<0.001 |
Growth: From 16 months of age linear growth stabilized at the 10th percentile of the Dutch references, whereas in the control group growth velocities were similar to the Dutch references. Comparison with birth weight data of the macrobiotic infants showed that retardation of weight growth already occurred before the age of four months. Weight growth was most depressed between eight months and 14 months, while stabilization at the 30th percentile level occurred between 14 months and 18 months.
Growth Relation with Diet: Both the energy intake and the protein content of the macrobiotic diet contributed independently to growth in weight and arm circumference. Chemical and biochemical observations from blood analysis revealed that macrobiotic children had:
- Elevated activity coefficient of erythrocyte glutathion reductase (secondary to low riboflavin intake)
- Iron deficiency, which was observed in 15% of macrobiotic infants (no anemia observed in control group)
- Low plasma vitamin B12, which was associated with an increase in mean corpuscular volume
- Clinical symptoms of rickets, which was observed in 28% of macrobiotic children in summer and 55% in winter
- Major skin and muscle wasting, which was present in 30% of the macrobiotic infants with growth velocities in weight and height were lower in these infants with w (P<0.05) and slower in motor development than other macrobiotic children (P=0.05)
- Significantly later gross motor development (P<0.001) and speech and language development (P<0.03) in the macrobiotic group.
Recommendations for the Macrobiotic Diet
- Add fat as an additional source of energy to a total of at least 25% to 30% of energy as fat
- Include fish (two to three portions per week) as a source of vitamin B12 and vitamin D (especially in winter)
- Increase consumption of plant sources of calcium and riboflavin.
Two-Year Follow-up Study
Diet: Few changes were found in the frequency of consumption of foods typical of the macrobiotic diet; some changes were observed in consumption of animal products as well as vegetable oil and vitamin D supplements.
Growth: Results were similar to earlier observations concerning linear growth retardation during the first two years of life and only partial catch-up during the following years.
Relation to Diet: In children whose consumption of fish and dairy products had increased since 1985, linear growth was significantly faster (P<0.05) than in other macrobiotic children. The data demonstrate that the observed linear growth retardation in children on macrobiotic diets is caused by nutritional deficiencies alone.
Consumption Frequency of Selected Foods by Children in Macrobiotic Families in 1985 (n=173) and in 1987 (n=152)
|
More than three times per week 1985 (1987) |
One to two times per week 1985 (1987) |
Fewer than once per week 1985 (1987) |
Fish |
3 (10) | 41 (64) |
58 (26) |
Sunflower/pumpkin seeds | 31 (48) | 32 (27) | 29 (25) |
Sesame seeds and pasta | 88 (89) | 3 (5) | 8 (6) |
Vegetable oil | 75 (92) | 12 (5) | 13 (3) |
Vitamin D supplement in winter | 9 (21) | 1 (1) | 89 (77) |
Dairy products | 14 (26) | 5 (12) | 81 (72) |
Tofu/tempeh | 77 (76) | 16 (20) | 8 (3) |
Leaf vegetables |
95 (97) |
1 (2) |
4 (2) |
Graphically, the increase in frequency per week of fish consumption is presented in Figure 1.
Figure 1. Changes in Consumption of Foods by Dutch Macrobiotic Families, 1985 to 1987
Stunting occurs in children whose diets are low in animal protein and factors associated with animal protein in foods. Efforts are needed to improve quality as well as quantity of the diets of preschool children.
University/Hospital: | Agricultural University Wageningen |
Although the children consumed less of key nutrients (vitamin B12, riboflavin, calcium, etc.), their curve for weight-for-height (most important indicator for growth in that it confirms that a child is growing proportionally) followed the median of the Dutch reference. No data were presented on mean vitamin D intake of macrobiotic infants age six months to 16 months during the mixed-longitudinal study prior to recommendations. There was no discussion about why there were 21 fewer subjects analyzed at two years after dietary recommendations (1987) vs. 1985.
Quality Criteria Checklist: Primary Research
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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? | No | |
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 | |
2.4. | Were the subjects/patients a representative sample of the relevant population? | Yes | |
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? | 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? | Yes | |
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.) | Yes | |
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.) | Yes | |
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? | 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? | N/A | |
5.1. | In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? | N/A | |
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.) | N/A | |
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.) | N/A | |
5.3. | In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? | Yes | |
5.3. | In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? | Yes | |
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? | N/A | |
6.1. | In RCT or other intervention trial, were protocols described for all regimens studied? | N/A | |
6.2. | In observational study, were interventions, study settings, and clinicians/provider described? | Yes | |
6.2. | In observational study, were interventions, study settings, and clinicians/provider described? | Yes | |
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? | 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? | No | |
6.7. | Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? | No | |
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? | 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)? | 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? | No | |
9.2. | Are biases and study limitations identified and discussed? | No | |
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? | No | |
10.1. | Were sources of funding and investigators' affiliations described? | No | |
10.2. | Was the study free from apparent conflict of interest? | Yes | |
10.2. | Was the study free from apparent conflict of interest? | Yes | |