Elevated plasma homocysteine is a risk factor for cardiovascular disease, dementia, cancer and adverse pregnancy outcomes. Increases in homocysteine levels are associated with low intakes of vitamin B12, vitamin B6 and folic acid as well as a lack of exercise, smoking and heavy coffee consumption. Research1 has investigated the effects of lifestyle changes on homocysteine levels using a population-based prospective study that was conducted on 7031 subjects in Norway. The subjects had their homocysteine levels measured in 1992-1993 and then again at a follow up in 1997-1999. Changes in vitamin status and vitamin supplement use were the strongest determinants of changes in homocysteine levels. Each unit increase in plasma folate (nmol/L) and vitamin B12 (pmol/L) was associated with a 0.2 and 0.1 µmol/L reduction in homocysteine, respectively. Those who started talking vitamin supplements has significant falls in plasma homocysteine levels.
These results support previous findings and suggest that homocysteine levels can be controlled by vitamin supplements. Homocysteine is a risk factor for a number of diseases but can be effectively controlled by increasing plasma levels of folate, vitamin B12 or vitamin B6. Vitamin supplements appear to be most effective at lowering homocysteine levels in subjects with the highest plasma homocysteine levels and lowest plasma folate levels. Although other variables in this study did reduce homocysteine levels (cessation of smoking, body weight loss, abstinence from coffee) the associations were weak, unclear or not conclusive across different ages groups. Vitamin B12 and vitamin B6 are effective at reducing homocysteine levels because they are required by the enzymes methionine synthase and cystathione β-synthase, which can metabolise homocysteine to methionine or cysteine, respectively. Folate is also required by methionine synthase in the role of tetrahydrofolate as a methyl donor.
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