Rumors of homocysteine’s death as a cardiovascular risk factor have been greatly exaggerated

I’ve made this point before. A recent editorial in Stroke entitled “Homocysteine: Call Off the Funeral” provides reasons in addition to those I cited. One factor is the increasing importance of vitamin B12 relative to folic acid as a determinant of elevated homocysteine levels. Increased fortification of foods with folic acid has diminished the incidence of folate deficiency and may be masking milder cases of B12 deficiency. Moreover, the shifting demographic toward an older population has increased the importance of B12 deficiency due to food-cobalamin malabsorption syndrome for which the optimal dose of oral vitamin B12 is unclear. Some of the vitamin trials used doses of vitamin B12 which may have been inadequate to overcome this common absorptive defect.