Vegetarian Nutrition

VN: Micronutrients in Pregnancy (2007)

• 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.
  • Evidence Summary: Micronutrient Intake and Pregnancy in Vegetarians
    • Detail
    • Quality Rating Summary
      For a summary of the Quality Rating results, click here.
    • Worksheets
      • Campbell-Brown M, Ward RJ, Haines AP, North WR, Abraham R, McFadyen IR, Turnlund JR, King JC. Zinc and copper in Asian pregnancies--is there evidence for a nutritional deficiency? Br J Obstet Gynaecol. 1985 Sep; 92 (9): 875-85.
      • Cheng PJ, Chu DC, Chueh HY, See LC, Chang HC, Weng DR. Elevated maternal midtrimester serum free beta-human chorionic gonadotropin levels in vegetarian pregnancies that cause increased false-positive Down syndrome screening results. Am J Obstet Gynecol. 2004 Feb;190(2):442-7.
      • Drake R, Reddy S, Davies J. Nutrient intake during pregnancy and pregnancy outcome of lacto-ovo-vegetarians, fish-eaters and non-vegetarians. Veg Nutr. 1998; 2: 45-52.
      • Ellis R, Kelsay JL, Reynolds RD, Morris ER, Moser PB, Frazier CW. Phytate:zinc and phytate X calcium:zinc millimolar ratios in self-selected diets of Americans, Asian Indians, and Nepalese. J Am Diet Assoc. 1987 Aug;87(8):1043-7.
      • Ganpule A, Yajnik CS, Fall CH, Rao S, Fisher DJ, Kanade A, Cooper C, Naik S, Joshi N, Lubree H, Deshpande V, Joglekar C. Bone mass in Indian children--relationships to maternal nutritional status and diet during pregnancy: the Pune Maternal Nutrition Study. J Clin Endocrinol Metab. 2006 Aug; 91 (8): 2,994-3,001. Epub, 2006, May 30.
      • King JC, Stein T, Doyle M. Effect of vegetarianism on the zinc status of pregnant women. AJCN 1981 34: 1049-1055.
      • Koebnick C, Heins UA, Hoffmann I, Dagnelie PC, Leitzmann C. Folate Status during Pregnancy in Women Is Improved by Long-term High Vegetable Intake Compared with the Average Western Diet. J Nutr. 2001 131:733-739.
      • Koebnick C, Hoffmann I, Dagnelie PC, Heins UA, Wickramasinghe SN, Ratnayaka ID, Gruendel S, Lindemans J, Leitzmann C. Long-term ovo-lacto vegetarian diet impairs vitamin B-12 status in pregnant women. J Nutr. 2004 Dec;134(12):3319-26.
      • Koebnick C, Leitzmann R, Garcia AL, Heins UA, Heuer T, Golf S, Katz N, Hoffmann I, Leitzmann C. Long-term effect of a plant-based diet on magnesium status during pregnancy. Eur J Clin Nutr. 2005 Feb;59(2):219-25.
      • 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.
  • Search Plan and Results: VN: Vegetarian Nutrition During Pregnancy 2006
     
  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.
  • Evidence Summary: Micronutrient Bioavailability and Vegetarian Diets in Pregnancy
    • Detail
    • Quality Rating Summary
      For a summary of the Quality Rating results, click here.
    • Worksheets
      • Campbell-Brown M, Ward RJ, Haines AP, North WR, Abraham R, McFadyen IR, Turnlund JR, King JC. Zinc and copper in Asian pregnancies--is there evidence for a nutritional deficiency? Br J Obstet Gynaecol. 1985 Sep; 92 (9): 875-85.
      • Cheng PJ, Chu DC, Chueh HY, See LC, Chang HC, Weng DR. Elevated maternal midtrimester serum free beta-human chorionic gonadotropin levels in vegetarian pregnancies that cause increased false-positive Down syndrome screening results. Am J Obstet Gynecol. 2004 Feb;190(2):442-7.
      • Ellis R, Kelsay JL, Reynolds RD, Morris ER, Moser PB, Frazier CW. Phytate:zinc and phytate X calcium:zinc millimolar ratios in self-selected diets of Americans, Asian Indians, and Nepalese. J Am Diet Assoc. 1987 Aug;87(8):1043-7.
      • Koebnick C, Heins UA, Hoffmann I, Dagnelie PC, Leitzmann C. Folate Status during Pregnancy in Women Is Improved by Long-term High Vegetable Intake Compared with the Average Western Diet. J Nutr. 2001 131:733-739.
      • Koebnick C, Hoffmann I, Dagnelie PC, Heins UA, Wickramasinghe SN, Ratnayaka ID, Gruendel S, Lindemans J, Leitzmann C. Long-term ovo-lacto vegetarian diet impairs vitamin B-12 status in pregnant women. J Nutr. 2004 Dec;134(12):3319-26.
      • 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.
  • Search Plan and Results: VN: Vegetarian Nutrition During Pregnancy 2006
     
• 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.
  • Evidence Summary: Infant Health Outcomes and Maternal Vegetarian Diets
    • Detail
    • Quality Rating Summary
      For a summary of the Quality Rating results, click here.
    • Worksheets
      • Campbell-Brown M, Ward RJ, Haines AP, North WR, Abraham R, McFadyen IR, Turnlund JR, King JC. Zinc and copper in Asian pregnancies--is there evidence for a nutritional deficiency? Br J Obstet Gynaecol. 1985 Sep; 92 (9): 875-85.
      • Campbell-Brown M, Ward RJ, Haines AP, North WR, Abraham R, McFadyen IR, Turnlund JR, King JC. Zinc and copper in Asian pregnancies--is there evidence for a nutritional deficiency? Br J Obstet Gynaecol. 1985 Sep; 92 (9): 875-85.
      • Cheng PJ, Chu DC, Chueh HY, See LC, Chang HC, Weng DR. Elevated maternal midtrimester serum free beta-human chorionic gonadotropin levels in vegetarian pregnancies that cause increased false-positive Down syndrome screening results. Am J Obstet Gynecol. 2004 Feb;190(2):442-7.
      • Cheng PJ, Chu DC, Chueh HY, See LC, Chang HC, Weng DR. Elevated maternal midtrimester serum free beta-human chorionic gonadotropin levels in vegetarian pregnancies that cause increased false-positive Down syndrome screening results. Am J Obstet Gynecol. 2004 Feb;190(2):442-7.
      • Drake R, Reddy S, Davies J. Nutrient intake during pregnancy and pregnancy outcome of lacto-ovo-vegetarians, fish-eaters and non-vegetarians. Veg Nutr. 1998; 2: 45-52.
      • Drake R, Reddy S, Davies J. Nutrient intake during pregnancy and pregnancy outcome of lacto-ovo-vegetarians, fish-eaters and non-vegetarians. Veg Nutr. 1998; 2: 45-52.
      • Ganpule A, Yajnik CS, Fall CH, Rao S, Fisher DJ, Kanade A, Cooper C, Naik S, Joshi N, Lubree H, Deshpande V, Joglekar C. Bone mass in Indian children--relationships to maternal nutritional status and diet during pregnancy: the Pune Maternal Nutrition Study. J Clin Endocrinol Metab. 2006 Aug; 91 (8): 2,994-3,001. Epub, 2006, May 30.
      • Ganpule A, Yajnik CS, Fall CH, Rao S, Fisher DJ, Kanade A, Cooper C, Naik S, Joshi N, Lubree H, Deshpande V, Joglekar C. Bone mass in Indian children--relationships to maternal nutritional status and diet during pregnancy: the Pune Maternal Nutrition Study. J Clin Endocrinol Metab. 2006 Aug; 91 (8): 2,994-3,001. Epub, 2006, May 30.
      • North K, Golding J. A maternal vegetarian diet in pregnancy is associated with hypospadias. The ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood. BJU Int. 2000 Jan;85(1):107-13.
      • North K, Golding J. A maternal vegetarian diet in pregnancy is associated with hypospadias. The ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood. BJU Int. 2000 Jan;85(1):107-13.
      • Reddy S, Sanders TA, Obeid O. The influence of maternal vegetarian diet on essential fatty acid status of the newborn. Eur J Clin Nutr 1994;48:358-368
      • Reddy S, Sanders TA, Obeid O. The influence of maternal vegetarian diet on essential fatty acid status of the newborn. Eur J Clin Nutr 1994;48:358-368
      • 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.
      • 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.
  • Search Plan and Results: VN: Vegetarian Nutrition During Pregnancy 2006