B vitamins and Alzheimer's Disease

It is encouraging to hear something positive about vitamins in the media, for a change. However, research in relation to B vitamins and homocysteine metabolism and Alzheimer’s Disease (AD) is not new. High homocysteine can contribute to AD by vascular damage and direct neurotoxicity (Aisen et al 2008). Kado et al (2005) also confirmed that low levels of B6, B12 and folate were predictors of cognitive function and decline in older adults.

However, we must not forget other contributing factors to AD such as heavy drinking; alcohol depletes folic acid, contributing to memory loss (A Harvard Medical School Special Health Report 2008:28).

High refined carbohydrates and sugars have also been implicated, as they result in prolonged excessive insulin secretion, which leads to elevated blood levels of beta amyloid (A Harvard Medical School Special Health Report 2008:21) and accelerated cellular damage in cerebral neurons (Henderson 2004).

Farooqui et al (2007) suggested that n3 eicosanoids derived from EPA and DHA retard neuro-inflammation, oxidative stress, and apoptotic cell death in the brain tissue. They also found that ingredients of fish oil inhibit generation of beta-amyloid.

Fascinatingly, research in mice shows that moderate coffee drinking may have protective effect on AD as it lowers beta-amyloid (Abeta) levels (Arendash et al 2006).

References:

Arendash GW Schleif W Rezai-Zadeh K Jackson EK Zacharia LC Cracchiolo JR Shippy D Tan J (2006) Caffeine protects Alzheimer's mice against cognitive impairment and reduces brain beta-amyloid production Neuroscience 142 4 941-52

Aisen PS Schneider LS Sano M Diaz-Arrastia R van Dyck CH Weiner MF Bottiglieri T Jin S Stokes KT Thomas RG Thal LJ Alzheimer Disease Cooperative Study (2008) High-dose B vitamin supplementation and cognitive decline in Alzheimer disease: a randomized controlled trial The Journal of the American Medical Association 300 15 1774-83

Farooqui AA Ong WY Horrocks LA Chen P Farooqui T (2007) Comparison of biochemical effects of statins and fish oil in brain: the battle of the titans Brain Research Reviews 56 2 443-71

Harvard Medical School (2008) Improving Memory Understanding age-related memory loss Harvard Health Publications

Henderson ST (2004) High carbohydrate diets and Alzheimer's disease Medical Hypothesis 62 5 689-700

Kado DM Karlamangla AS Huang MH Troen A Rowe JW Selhub J Seeman TE (2005) Homocysteine versus the vitamins folate, B6, and B12 as predictors of cognitive function and decline in older high-functioning adults: MacArthur Studies of Successful Aging The American Journal of Medicine 118 2 161-7