Long-term ovo-lacto vegetarian diet impairs vitamin B-12 status in pregnant women.

Title
Long-term ovo-lacto vegetarian diet impairs vitamin B-12 status in pregnant women.
Source
Journal of Nutrition. 134, (12): 3319-3326, 2004.

It has been suggested that a well-planned vegetarian diet is adequate during pregnancy. This study compared serum vitamin B12 and homocysteine concentration in pregnant women consuming vegetarian and average Western diets and to evaluate the adequacy of current dietary reference intakes of vitamin B12 for these women.

Pregnant women adhering to plant food-based diets for at least 3 yr (ovo-lacto vegetarians (OLV), low-meat eaters (LME)) and women eating an average Western diet (control group) were recruited. Dietary vitamin B12 intake, serum vitamin B12 and plasma total homocysteine (tHcy) concentration were measured in wk 9-12, 20-22 and 36-38 of pregnancy. During pregnancy serum vitamin B12 concn. of OLV and LME were lower than those of the control group.

The combination of low serum vitamin B12 concn. and elevated plasma tHcy was observed in 22% of OLV, in 10% of LME and in 3% of controls. In OLV, serum vitamin B12 predicted 60% of the plasma tHcy variation, but in LME and controls only less than 10%.

Serum vitamin B12 concn. increased and plasma tHcy decreased sharply with increasing dietary intake of vitamin B12 toward a cutoff point of 3 mug/day. It is concluded that pregnant women consuming a long-term predominantly vegetarian diet have an increased risk of vitamin B12 deficiency.