UC Davis

Plant-based diets may increase the risk of vitamin B₁₂ deficiency due to limited intake of animal-source foods, while dietary folate increases when adhering to plant-based diets. In this cross-sectional study, we evaluated the B₁₂ and folate status of Norwegian vegans and vegetarians using dietary B₁₂ intake, B₁₂ and folic acid supplement use, and biomarkers (serum B₁₂ (B₁₂), plasma total homocysteine (tHcy), plasma methylmalonic acid (MMA) and serum folate). Vegans (n 115) and vegetarians (n 90) completed a 24-h dietary recall and a FFQ and provided a non-fasting blood sample. cB₁₂, a combined indicator for evaluation of B₁₂ status, was calculated. B₁₂ status was adequate in both vegans and vegetarians according to the cB₁₂ indicator; however 4 % had elevated B₁₂. Serum B₁₂, tHcy, MMA concentrations and the cB₁₂ indicator (overall median: 357 pmol/l, 9·0 µmol/l, 0·18 µmol/l, 1·30 (cB₁₂)) did not differ between vegans and vegetarians, unlike for folate (vegans: 25·8 nmol/l, vegetarians: 21·6 nmol/l, P = 0·027). Serum B₁₂ concentration < 221 pmol/l was found in 14 % of all participants. Vegetarians revealed the highest proportion of participants below the recommended daily intake of 2 µg/d including supplements (40 v. 18 %, P < 0·001). Predictors of higher serum B₁₂ concentrations were average daily supplement use and older age. Folate deficiency (< 10 nmol/l) was uncommon overall (< 2·5 %). The combined indicator cB₁₂ suggested that none of the participants was B₁₂-depleted; however, low serum B₁₂ concentration was found in 14 % of the participants. Folate concentrations were adequate, indicating adequate folate intake in Norwegian vegans and vegetarians.