26 September 2006
There may be a connection between dietary deficiencies and Alzheimer's disease. In a special issue of the Journal of Alzheimer's Disease published this month, ten contributions from worldwide experts in the field examine possible linkages between folate and homocysteine and Alzheimer's disease.
In the lead article Guest Editor Thomas Shea, Professor and Director of the Center for Cellular Neurobiology and Neurodegeneration Research, University of Massachusetts Lowell, suggests “Alzheimer’s disease has a multifactoral etiology, encompassing genetic and nutritional risk factors, and no single risk factor can account for all cases.…A genetic predisposition may remain latent pending an age-related critical decline in nutrition. This has confounded the linkage of nutrition to Alzheimer’s disease, since contributing nutritional deficiencies may remain undetected, and, even if considered, may not receive sufficient attention if they are benign in isolation.”
Andrew McCaddon from the Wales College of Medicine contributes some historical perspective on homocysteine and folate levels and the development of dementia, including some discussion of the potential for reversing such declines.
Aron M. Troen and colleagues from Tufts University write of their studies of mice fed diets to create excess homocysteine levels and then tested for cognitive functions. Sudha Seshadri discusses whether elevated homocysteine levels is a risk factor for dementia or merely a risk marker for some underlying process. Amy Chan and Thomas B. Shea then examine the connection between dietary deficiencies of folate and Vitamin E and the development of neurofibrillary tangles of tau protein, a hallmark of Alzheimer's disease.
Moving on to possible therapies, Sigfrido Scarpa and colleagues at the University of Rome investigated S-adenosylmethionine (SAM) metabolism in cell cultures, which might be used to interfere with amyloid-ß overproduction, another characteristic of AD. In a second contribution from that institution, Rosaria A. Cavallaro and co-workers looked at whether SAM administration influences gene expression in the brain.
Flaubert Tchantchou of the University of Maryland School of Pharmacy discusses the various metabolic processes involved in homocysteine regulation and the various consequences of folate deficiency.
Folate is one of the B vitamins. Martha Clare Morris and colleagues at the Rush University Medical Center expand on the possible role of all of the B vitamins in cognitive decline and comment on the potential benefits and harms of vitamin supplementation. In another contribution, Morris and coworkers report on a prospective cohort study of 1041 patients where dietary folate, B-12 and B-6 levels were not associated with the development of Alzheimer's disease.