Clarke et al's article1 in the November 1998 ARCHIVES issue reinforcing an association between histopathologically confirmed Alzheimer disease and low serum levels of vitamin B12 and folate is of considerable interest and of obvious importance. An association between vitamin B12 deficiency and Alzheimer disease was first suggested in 1983,2 although there is only 1 previous report3 of low vitamin B12 values associated with confirmed Alzheimer pathology in a kindred with early-onset familial Alzheimer disease.
McCaddon A, Davies G, Hudson P. Nutritionally Independent B12 Deficiency and Alzheimer Disease. Arch Neurol. 2000;57(4):607-608. doi:10.1001/archneur.57.4.607