• Intervention
    What are patterns of micronutrient intake among pregnant vegetarians?
    • Conclusion

      Based on ten studies, two of which were conducted in the US, only the following micronutrients had lower intake among vegetarians than non-vegetarians:

      • B-12
      • Vitamin C
      • Calcium
      • Zinc

      Vegetarians did not meet dietary standard (in at least one country) for:

      • B-12 (in UK)
      • Iron (in US, for both vegetarians and omnivores)
      • Folate (in Germany, though lower rate of deficiency than among omnivores)
      • Zinc (in UK)
    • Grade: III
      • Grade I means there is Good/Strong evidence supporting the statement;
      • Grade II is Fair;
      • Grade III is Limited/Weak;
      • Grade IV is Expert Opinion Only;
      • Grade V is Not Assignable.
      • High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
      • Moderate (B) means we are moderately confident in the effect estimate;
      • Low (C) means our confidence in the effect estimate is limited;
      • Very Low (D) means we have very little confidence in the effect estimate.
      • Ungraded means a grade is not assignable.
    What is the bioavailability of different micronutrients in pregnant vegetarians?
    • Conclusion

      Six studies (five non-US, one with combined US and non-US samples; all but one of positive quality) were identified that examined the bioavailability of different micronutrients in vegetarian versus non-vegetarian pregnant women. Of the micronutrients examined in the research, only serum B12 levels were significantly lower in non-vegan vegetarians than non-vegetarians. Additionally, one study reported that lower B12 levels are more likely to be associated with high serum tHCY in ovolactovegetarians than low meat eaters or omnivores.

      While zinc levels were not significantly different between non-vegan vegetarians and non-vegetarians, vegetarians who have a high intake of calcium may be at risk for zinc deficiency (because of the interaction between phytate, calcium and zinc).

      Based on limited evidence, plasma folate levels may actually be higher among some vegetarian groups than non-vegetarians.

    • Grade: III
      • Grade I means there is Good/Strong evidence supporting the statement;
      • Grade II is Fair;
      • Grade III is Limited/Weak;
      • Grade IV is Expert Opinion Only;
      • Grade V is Not Assignable.
      • High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
      • Moderate (B) means we are moderately confident in the effect estimate;
      • Low (C) means our confidence in the effect estimate is limited;
      • Very Low (D) means we have very little confidence in the effect estimate.
      • Ungraded means a grade is not assignable.
  • Monitoring and Evaluation
    What are birth outcomes associated with the micronutrient intake of maternal vegetarian diets?
    • Conclusion

      Limited evidence from 7 studies (all outside the U.S.) indicated that the micronutrient content of a balanced maternal vegetarian diets does not have detrimental outcomes for the health of the child at birth.

      There may be, however, a risk for a false positive diagnosis of Down Syndrome in the fetus when maternal serum free beta-human chorionic gonadotropin (BhCG) and alpha fetoprotein (AFP) levels are used as markers in vegetarian mothers.

    • Grade: III
      • Grade I means there is Good/Strong evidence supporting the statement;
      • Grade II is Fair;
      • Grade III is Limited/Weak;
      • Grade IV is Expert Opinion Only;
      • Grade V is Not Assignable.
      • High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
      • Moderate (B) means we are moderately confident in the effect estimate;
      • Low (C) means our confidence in the effect estimate is limited;
      • Very Low (D) means we have very little confidence in the effect estimate.
      • Ungraded means a grade is not assignable.