Vitamin B12 status of vegetarians in Shanghai

Objective To investigate the vitamin B12 status of vegetarians in Shanghai. Methods A total of 282 adult vegetarians and 282 omnivores matching by gender and age were recruited in Shanghai. Their dietary intakes were collected. The serum concentrations of vitamin B12, folate and homocysteine were tested. The red blood cell, hematocrit value, mean corpuscular volume and mean erythrocyte width were also examined. Results The daily average intake of dietary vitamin B12 was(0.46±1.01) μg/d in vegetarians and only (0.1±0.46) μg/d in vegans, which was lower than that of omnivores [(3.91±6.92)μg/d, F=50.57, P<0.01] . 137 omnivores and 274 vegetarians had less dietary vitamin B12 level than recommended nutrient intake (RNI) and the difference was statistically significant (χ2=114.77, P<0.01). 54.26% of vegetarians, 68.92% vegans, 49.04% ovo-lacto vegetarians and 15.60% omnivores had hyperhomocysteinemia and the differences between vegetarians and omnivores were statistically significant (all P<0.01). After adjusting the confounding factors the hematocrit value was higher in vegetarians, vegans and ovo-lacto vegetarians than in omnivores(27.42%±18.32%, 28.73%±18.19%, 26.95%±18.38% vs. 8.96%±16.59%, P<0.01). Vegans had lower red blood cell counts and higher hematocrit value and mean corpuscular volume than omnivores. Conclusion Vitamin B12 deficiency combined with an elevated level of homocysteine and red blood cell volume growth are common but serious issue in vegetarians, especially in vegans. Key words: Vegetarian; Vitamin B12; Red blood cell; Homocysteine; Folate