I pazienti che hanno un lieve deficit cognitivo che precede l'insorgenza dell'Alzheimer potrebbero avere dei vantaggi dall'assunzione di alte dosi di vitamine del gruppo B. Lo suggerisce uno studio dell'Università di Oxford pubblicato dalla rivista Pnas, secondo cui i supplementi rallentano la perdita di materia grigia. I ricercatori hanno studiato 156 soggetti over 70 che soffrivano di lieve deficit cognitivo. Metà degli anziani ha ricevuto un cockatil di 20 milligrammi di vitamina B6, 0,5 milligrammi di B12 e 0,8 di acido folico, mentre l'altra metà ha avuto un placebo. Dopo due anni tutti i soggetti hanno perso materia grigia, ma mentre il gruppo del placebo ne ha perso il 3,7%, nell'altro la diminuzione è stata dello 0,5. "Le aree meno colpite - sottolineano gli autori - sono proprio quelle associate allo sviluppo dell'Alzheimer"

 

Preventing Alzheimer’s disease-related gray matter atrophy by B-vitamin treatment

1. Gwenaëlle Douauda,b,1,

2. Helga Refsumb,c,d,

3. Celeste A. de Jagerc,

4. Robin Jacobye,

5. Thomas E. Nicholsa,f,g,

6. Stephen M. Smitha, and

7. A. David Smithb,c

Author Affiliations

1. Edited by Marcus E. Raichle, Washington University in St. Louis, St. Louis, MO, and approved March 29, 2013 (received for review January 29, 2013)

Abstract

Is it possible to prevent atrophy of key brain regions related to cognitive decline and Alzheimer’s disease (AD)? One approach is to modify nongenetic risk factors, for instance by lowering elevated plasma homocysteine using B vitamins. In an initial, randomized controlled study on elderly subjects with increased dementia risk (mild cognitive impairment according to 2004 Petersen criteria), we showed that high-dose B-vitamin treatment (folic acid 0.8 mg, vitamin B6 20 mg, vitamin B12 0.5 mg) slowed shrinkage of the whole brain volume over 2 y. Here, we go further by demonstrating that B-vitamin treatment reduces, by as much as seven fold, the cerebral atrophy in those gray matter (GM) regions specifically vulnerable to the AD process, including the medial temporal lobe. In the placebo group, higher homocysteine levels at baseline are associated with faster GM atrophy, but this deleterious effect is largely prevented by B-vitamin treatment. We additionally show that the beneficial effect of B vitamins is confined to participants with high homocysteine (above the median, 11 µmol/L) and that, in these participants, a causal Bayesian network analysis indicates the following chain of events: B vitamins lower homocysteine, which directly leads to a decrease in GM atrophy, thereby slowing cognitive decline. Our results show that B-vitamin supplementation can slow the atrophy of specific brain regions that are a key component of the AD process and that are associated with cognitive decline. Further B-vitamin supplementation trials focusing on elderly subjets with high homocysteine levels are warranted to see if progression to dementia can be prevented.

 

Fonte: Sanita News