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Objective: To compare dietary magnesium intake and magnesium concentrations in serum, red blood cells (RBC) and urine during pregnancy of women habitually following a long-term plant-based diet and of women following an average Western (control) diet., Design: Prospective study during pregnancy., Setting: Giessen, Germany., Subjects: Healthy pregnant women (n=108) in their 9-12th, 20-22nd and 36-38th gestational week habitually following a plant-based diet for more than 3 y or an average Western diet. The vegetarians were subdivided into ovo-lacto vegetarians (n=27) and low-meat eaters (n=43)., Results: Significant higher dietary magnesium intakes were observed in pregnant women consuming a plant-based diet (508+/-14 mg/day for ovo-lacto vegetarians, P<0.001 and 504+/-11 mg/day for low-meat eaters, P<0.001) than in pregnant women consuming a control diet (412+/-9 mg/day). Serum magnesium concentrations were similar in all diet groups whereas RBC magnesium was slightly higher in low-meat eaters than in controls (P=0.058). Urinary magnesium excretion was higher in ovo-lacto vegetarians (P=0.023), followed by low-meat eaters (P=0.017) when compared to the control group. During the third trimester of pregnancy, the frequency and the occurrence of calf cramps was lower in the plant-based diet group than in the control group (P=0.004 and 0.008)., Conclusions: Owing to a higher dietary magnesium intake confirmed by higher urinary magnesium excretion, habitual plant-based diets result in a slightly improved magnesium status during pregnancy and reduce the frequency of calf cramps during the third trimester of pregnancy compared to an average Western diet. Therefore, plant-based diets during pregnancy can be recommended with regard to magnesium supply.

A well-planned vegetarian diet has been stated to be adequate during pregnancy. The aim of the present study was to compare serum vitamin B-12 and homocysteine concentrations in pregnant women (n = 109) consuming vegetarian and Western diets and to evaluate the adequacy of current dietary reference intakes of vitamin B-12 for these women. Pregnant women adhering to vegetarian diets for at least 3 y, with subgroups of ovo-lacto vegetarians (OLVs; n = 27), low-meat eaters (LME, n = 43), and women eating an average Western diet (control group, n = 39), were recruited. Dietary vitamin B-12 intake, serum vitamin B-12, and plasma total homocysteine (tHcy) concentrations were measured in wk 9-12, 20-22, and 36-38 of pregnancy. During pregnancy serum vitamin B-12 concentrations of ovo-lacto vegetarians (P < 0.001) and low-meat eaters (P = 0.050) were lower than those of the control group. We observed the combination of low serum vitamin B-12 concentrations and elevated plasma tHcy in 22% of ovo-lacto vegetarians, in 10% of low-meat eaters, and in 3% of controls (P = 0.003). In OLVs, serum vitamin B-12 predicted 60% of the plasma tHcy variation (P < 0.001), but in LMEs and controls only <10% (NS). Serum vitamin B-12 concentrations increased and plasma tHcy decreased sharply with increasing dietary intake of vitamin B-12 toward a cutoff point of 3 mug/d. Pregnant women consuming a long-term predominantly vegetarian diet have an increased risk of vitamin B-12 deficiency. Current recommended dietary intakes urgently need reevaluation.

Background: Because reference values for vitamin B(12) concentrations and vitamin B(12)-binding capacities for pregnant women have not been established, the reference values for nonpregnant women are often applied to assess vitamin B(12) status. The aim of the present study was to describe ranges of biochemical indices of vitamin B(12) status, including red blood cell (RBC) vitamin B(12), saturated and unsaturated cobalamin-binding proteins, and binding capacities in all trimesters of uncomplicated pregnancy., Methods: A total of 39 healthy pregnant women with long-term daily intake of vitamin B(12) >2.6 microg/day and uncomplicated pregnancies participated in the study throughout their pregnancies. RBCs and serum vitamin B(12), holo-haptocorrin, unsaturated cobalamin-binding proteins, unsaturated and total vitamin B(12)-binding capacities, total homocysteine (tHcy), and RBC count were assessed in weeks 9-12, 20-22, and 36-38 of gestation., Results: Significant changes in vitamin B(12) status occurred in the course of pregnancy. Serum vitamin B(12) concentrations and percentage of saturation of vitamin B(12)-binding proteins decreased steadily throughout pregnancy. In the third trimester, 35% of the participants had serum vitamin B(12) concentrations <150 pmol/L and 68.6% had <15% saturation of total vitamin B(12)-binding capacities, but no women had RBC vitamin B(12) concentrations <148 pmol/L. However, the decrease in these indices was not associated with reduced hemoglobin concentrations or RBC count or with increased tHcy concentrations., Conclusions: Our findings suggest that the reference values for vitamin B(12) status in nonpregnant women may not be applicable to pregnant women.

The effect of increasing dietary folate on folate status during pregnancy is controversial. The aim of this study was to compare folate intake and folate status during pregnancy of women with high long-term vegetable intake and those eating an average Western diet. In a prospective study that included 109 participants, pregnant women adhering to a predominant vegetarian diet with high vegetable intake for 8 +/- 0.5 y with subgroups of ovo-lacto vegetarians (n = 27) and low meat eaters (n = 43) and women eating an average Western diet (control group, n = 39) were compared with regard to dietary intake and plasma and red blood cell (RBC) folate concentrations during wk 9-12, 20-22 and 36-38 of gestation. Plasma and RBC folate concentrations were highest in ovo-lacto vegetarians, followed by low meat eaters and lowest in the controls. Ovo-lacto vegetarians and low meat eaters showed a lower risk for folate deficiency, with RBC folate concentrations of <320 nmol/L resulting in odds ratios of 0.10 (95% confidence interval, 0.01-0.56) and 0.52 (95% confidence interval, 0.20-1.34), respectively. In ovo-lacto vegetarians, the RBC folate concentration was positively related to the intake of vitamin B-12 (r = 0.51, P: < 0.0001). The results of the study suggest that long-term high vegetable intake favorably affects plasma folate as well as RBC folate concentrations throughout pregnancy and reduces the risk of folate deficiency if an adequate vitamin B-12 supply is ensured.