Effect of nutrition at homocysteine levels

Remethylation pathway of homocysteine metabolism prevails under condition of lower methionine intake, e.g. in case of alternative nutrition with prevailing or exclusive plant consumption. Formation of methionine by remethylation of homocysteine requires vitamin B12 and folic acid as essential factors. The plasma homocysteine level was measured in alternative nutrition groups of adults (lacto + lacto-ovo-vegetarians; vegans) and compared with a group consuming traditional mixed diet (control). The average homocysteine level was higher in vegetarians than in control and the frequency of hyperhomocysteinemia was 27% vs. 7% in traditional group. In vegans the average hemocysteine value was 15.8 mumol/L and 48% of individual values exceeded 15 mumol/L. Serum vitamin B12 levels were significantly lower in alternative nutrition groups with eggs and dairy products as vitamin sources or, in vegans with bacteria in distal part of small intestine as the only vitamin source. Vitamin deficit was found in 34% of vegetarians and in 71% of vegans vs. 0% in control subjects. Serum folate values were significantly higher in the case of alternative nutrition. In the subjects on mixed diet consuming less legumes, whole-grain products, sprouts, seeds, vegetables and fruit the frequency of folate deficit was found in 16% of individual values vs. in 2% of values in alternative groups. The results show that mild hyperhomocysteinemia in alternative nutrition is a consequence of vitamin B12 deficiency. Under condition of traditional nutrition, higher homocysteine levels in healthy individuals (genetic factors and hypernutrition excluded) may be a consequence of folic acid deficit.