Background: Vitamin B12 deficiency during pregnancy has been associated with adverse health outcomes, including maternal anemia, preeclampsia, intrauterine growth restriction, and neural tube defects. The objective of this analysis was to examine the dietary correlates of vitamin B12 status in pregnant women participating in a prospective cohort study in Southern India.

Methods: Participants were 400 pregnant women (< 14 weeks gestation) enrolled in a cohort study. Dietary intake was assessed using a validated, interviewer-administered, semi-quantitative food frequency questionnaire, which assessed dietary intake of 108 food items. Serum vitamin B12 was measured via electrochemiluminescence; vitamin deficiency was defined as vitamin B12 concentrations less than 148.0 pmol/L. Linear and binomial regression models were used to examine the associations between dietary variables (i.e., food groups, nutrients) and vitamin B 12 status.

Results: The median daily vitamin B12 intake was 1.7 microg (IQR: 1.1--2.5), and 63.3% of participants were vitamin B12 deficient. In food group analyses, consumption of egg-based foods, organ meats, red meat, and grams were associated with higher serum vitamin B12 concentrations; consumption of pulses and fruit-based foods were associated with lower vitamin B12 concentrations. Similarly, increased consumption of egg-based foods (RR: 0.99, 95% CI: 0.98--0.99, p = 0.023), milk products (0.99, 0.99--0.99, p = 0.038), and total meat 0.80 (0.69--0.93, p = 0.004) were associated with significantly lower risk for vitamin B12 deficiency. In nutrient increased intake of vitamin B12; saturated (caprylic, capric, lauric, stearic), monounsaturated (palmitoleic), and polyunsaturated (linolenic, arachidonic, timnodonic, cervonic) fatty acids; cholesterol; iodine; and most amino acids (tryptophan, threonine, isoleucine, leucine, lysine, methionine, cysteine, tyrosine, valine, alanine, aspartic acid, serine) were associated with higher serum vitamin B12 concentrations and lower risk for vitamin B12 deficiency (p < 0.05).

Conclusion: Vitamin B12 intake was low in this population and was associated with risk for vitamin B12 deficiency. Low consumption of animal-source foods (i.e., milk, egg, and meat products) was associated with risk for vitamin B12 deficiency. Assessing dietary intake during early pregnancy is important to identify risk factors for vitamin B12 deficiency and to inform dietary recommendations.