Homocysteine levels in vegetarians versus omnivores

Vitamin B-12, folate, and vitamin B-6 are the main determinants of homocyst einemia. The vegan diet provides no vitamin B-12, but also less strict form s of alternative nutrition may suffer from a deficit of this vitamin. The p lasma homocysteine level was measured in alternative nutrition groups of ad ults (lacto- and lactoovovegetarians, n = 62; vegans, n = 32) and compared with the levels in a group consuming traditional diet (n = 59), omnivores). In the group of vegetarians the average homocysteine level is 13.18 vs. 10 .19 mu mol/l in omnivores; the frequency of hyperhomocysteinemia is 29 vs. 5% in omnivores. In the group of vegans the average homocysteine value is 1 5.79 mu mol/l (53% of the individual values exceeded 15 mu mol/l). Omnivore s consume the recommended amount of methionine; however, in individuals con suming an alternative diet, the intake of methionine is deficient (assessed by food frequency questionnaire; lower content of methionine in plant prot eins). Under conditions of lower methionine availability the remethylation pathway prevails; therefore, vitamin B-12 and folate were evaluated in rela tion to the homocysteine level. The serum vitamin B-12 levels are significa ntly lower in the alternative nutrition groups (214.8 pmol/l in vegetarians , 140.1 pmol/l in vegans vs. 344.7 pmol/l in omnivores); a deficit (<179.0 pmol/l) was found in 26% of the vegetarians and in 78% of the vegans vs. 0% in omnivores. The serum folate levels were within the range of reference v alues in all groups; however, they were significantly lower in omnivores. T he results show that the mild hyperhomocysteinemia in alternative nutrition is a consequence of vitamin B-12 deficiency. Copyright (C) 2000 S. Karser AG, Basel.