Vegetarian Nutrition

VN: Micronutrients in Pregnancy (2007)

Citation:

Ward RJ, Abraham R, McFadyen IR, Haines AD, North WR, Patel M, Bhatt RV. Assessment of trace metal intake and status in a Gujerati pregnant Asian population and their influence on the outcome of pregnancy. Br J Obstet Gynaecol. 1988 Jul;95(7):676-82.

PubMed ID: 3415934
 
Study Design:
Cross-Sectional study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To identify whether the diet and biochemical indices of pregnant vegetarian and non-vegetarian women from India had been influenced since immigration to the UK.
Inclusion Criteria:

Healthy pregnant vegetarian and non-vegetarian Gujerati Indian women recruited from 2 outpatient clinics in Baroda, Gujerat, India.

Data compared with previous study data on vegetarian and non-vegetarian Asian women living in Harrow who had emigrated to Britain during the previous decade.

 

Exclusion Criteria:

Non-pregnant women

Description of Study Protocol:

Recruitment

Healthy pregnant vegetarian and non-vegetarian Gujerati Indian women recruited from 2 outpatient clinics in Baroda, Gujerat, India.

 

Design Information collected:

  • dietary assessment
  • 7 day dietary recall
  • social class inforamtion based on husband's occupation
  • social history
  • height
  • weight
  • parity
  • age
  • pregnancy complications
  • hemoglobin
  • worm infestation
  • tabacco use
  • delivery and birthweigth detail

Data compared with previous study data on vegetarian and non-vegetarian Asian women living in Harrow who had emigrated to Britain during the previous decade

Blinding used (if applicable) NA

 

Intervention (if applicable)NA

 

Statistical Analysis: Means of different groups compared and statistical significance calculated

Data Collection Summary:

Timing of Measurements: During pregnancy and pregnancy outcome measurements

Dependent Variables

  • Biochemical indices
  • Pregnancy outcomes

Independent Variables

  • Diet (vegetarian vs. non-vegetarian)

Control Variables

  • country of residence (UK versus India)
Description of Actual Data Sample:

 

Initial N:

  • 73 pregnant women recruited from Gujerati clinics (53 vegetarians, 20 non-vegetarians)
  • 31 subjects provided follow-up data on delivery and birthweight. This was limited due to some women moving away and others difficult to trace because of large throughput in the Obstetric department of the Hospital
  • Data compared to previous study of 92 Harrow Asian population who were approximately 28 weeks gestations (59 vegetarians, 33 non-vegetarians)

Attrition (final N): All data provided for initial (73) women; and follow up data for (31) women and their infants

Age: Not reported

Ethnicity: Gujerati, India women in this study; compared to Asian women, most of whom emigrated to Britain from Gujerati, India

Other relevant demographics: Many of the women were Hindus

Summary of Results:

 

Maternal and Infant Characteristics

  • Indian women in Gujerat were about 10 kg lighter than the Harrow Indians
  • Mean birth weights in both vegetarian and non-vegetarian Gujerati groups were similar
  • If adjustment is made for the maternal size of the Gujerati Indian mothers, the birth weight of these Indian babies is relatively greater than that of those born in Harrow
  • Approximately half of the Gujerati Indians were of social class IV or V compared with 12% of the Harrow Indians
  • 50% of the Harrow Indians were of social class I or II; only 10% of the Gujerati Indians were of these social classes

Dietary Data

  • Zinc intake amoung the Gujerati Indians was only 25% of the RDA during pregnancy
  • Intakes of iron and copper were comparable to those of the Harrow Indians
  • Phytic acid:zinc ratios were similar in the Gujerati Indian vegetarian and non-vegetarian diet (15:9 and 14:0, respectively)
  • **This confirms that non-vegetarian diets merely implies the addition of small amounts of meat or fish to the diet. These non-vegetarian diets cannot be compared to a European non-vegetarian diet.

Plasma zinc and copper concentrations

  • Plasma zinc concentrations were similar in both the vegetarian and non-vegetarian Asian women
  • Levels were reduced below the normal range (10.5 – 18.0 micromol/L)
  • Mean copper levels were increased above the normal range (12.6-18.5 micromol/L)
  • Mean copper levels were similar in all 4 groups

Biochemical Indices

  • Mean albumin concentration was significantly lower in the plasma samples of both Gujerati groups when compared to their corresponding dietary group living in Harrow
  • There were significant correlations between the albumin concentrations and the concentration of sodium and calcium in both groups (r=0.635, P<0.01 and r=0.802, P<0.01 respectively)
  • However, correlations between the concentration of plasma albumin and zinc in Gujerati women was not significant

 

Mean daily dietary intake

 

Gujerat

Harrow

 

Vegetarian

(n=53)

Non-Vegetarian

(n=20)

Vegetarian

(n=59)

Non-Vegetarian

(n=33)

Energy (kcal)

1320 (529)*

1460 (635)*

1970 (523)*

2165 (460)*

Protein (g)

38 (17)*

43 (20)*

57 (16)*

75 (19)*

Zinc (mg)

5.0 (2.2)**

5.7 (2.5)*

7.5 (2.1)*

10.2 (3.0)*

Copper (mg)

1.2 (0.6)**

1.3 (0.6)***

1.5 (0.7)**

1.8 (0.8)***

Iron (mg)

9.7 (5.5)

11.4 (5.9)

11.1 (4.6)

12.8 (4.5)

Fibre (g)

18.6 (9.2)***

21.9 (11)

23.1 (6.9)***

22.8 (6.8)

Results are means (SD). Statistical significances are calculated between places within similar dietary groups

*P<0.001, ** P<0.02, ***P<0.05

Serum Biochemical Indices

 

Gujerat

Harrow

 

Non-Vegetarian

(n=13)

Vegetarian

(n=49)

Non-Vegetarian

(n=23)

Vegetarian

(n=41)

Alk:phos

130 (90)

107 (39)

105.7 (30)

109.5 (41)

Calcium

2.12 (0.11)

2.10 (0.21)

2.20 (0.11)

2.19 (0.11)

Total Protein

63 (5.1)

61 (7.7)

61 (4.4)

62 (4.6)

Albumin

31.9 (3.0)*

30.8 (3.9)**

34.9 (2.2)*

35.4 (2.3)**

Phosphate

1.11 (0.16)

1.20 (0.19)

1.06(0.21)

1.03 (0.25)

Bilirubin

5.6 (1.4)

6.3 (4.8)

6.4 (3.2)

6.8 (3.8)

Sodium

133 (4.1)

132 (7.6)

138 (6.1)

137 (2.5)

Potassium

3.8 (1.1)

3.7 (0.9)

4.03 (0.5)

4.19 (0.4)

Urea

2.47 (0.74)

2.6 (0.81)

2.9 (0.7)

2.7 (0.6)

Results are means (SD).  Statistical significances are calculated between places within similar dietary groups

*P<0.002, ** P<0.001

Author Conclusion:

Our results indicate that a diet depleted of zinc by approximately three-quarters of the US recommended dietary allowance during pregnancy was not detrimental to the outcome of pregnancy if birhtweight is the criterion of a successful outcome. Supplementation of the Indian Gujerati population with zinc during their pregnancy was clearly not indicated as there was no impairment of fetal development in this population when compared with the birthweights of either the other populations.

There was no obvious relation between the plasma copper concerntration at 28 weeks and birthweight.

Funding Source:
Government: North West Thames Regional Health Authority
Not-for-profit
0
Foundation associated with industry:
Reviewer Comments:

 

  • Able to look at how varied environment (due to immigration to UK) may have an effect on nutrient intakes, biochemical indices and pregnancy outcomes 
  • data collected on 2 separate groups that were originally from similar cultural ancestry
  • Study looked at animal intake and vegetarianism among both groups

 

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) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) N/A
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? ???
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? 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.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) ???
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  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? Yes
5. Was blinding used to prevent introduction of bias? ???
  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.) ???
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? ???
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  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
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? 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? 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
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? ???
  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
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes