Homocysteine and the Risk of Dementia

Abstract

Featured Article: Seshadri S, Beiser A, Selhub J, Jacques PF, Rosenberg IH, D'Agostino RB, et al. Plasma homocysteine as a risk factor for dementia and Alzheimer's disease. N Engl J Med 2002;346:476–83.3 In the late 1990s, I was working in a tertiary-care academic medical center in India and running a dementia clinic that had enrolled 120 patients in its first year. India is a country where centuries ago the influence of Buddhism and Jainism had persuaded a large proportion of the population to adopt a vegetarian diet; many others simply could not afford meat or fish. Perhaps as a consequence, as many as a fourth of the patients with dementia (and many without it) had low circulating vitamin B12 concentrations, but correcting this deficiency did not improve their dementia. Nor did most of them have macrocytic anemia, peripheral neuropathy, or other clinical signs of vitamin B12 deficiency. Vitamin B12, along with folate and B6, are essential cofactors in the conversion of homocysteine, a …