12.01.07
Indication: Cognitive decline
Source: Am J Clin Nutr, November 2007;86(5):1384-91.
Research:
Elevated total homocysteine (tHcy) concentrations have been associated with cognitive impairment, but it is unclear whether low vitamin B12 or folate status is responsible for cognitive decline. So researchers decided to examine the associations of cognitive decline with vitamin B12 and folate status in a longitudinal cohort study performed from 1993 to 2003 in Oxford, U.K. Cognitive function was assessed with the Mini-Mental State Examination on at least three occasions during 10 years and related to serum concentrations of vitamin B12, holotranscobalamin (holoTC), tHcy, methylmalonic acid (MMA), and folate with the use of linear mixed models in 1648 participants who provided blood in 1995.
Results: Cognitive function declined abruptly at younger ages in some participants but remained intact in others until very old age. In multivariate regression analyses after adjustment for established risk factors, concentrations of holoTC (a marker of reduced vitamin B12 status), tHcy, and MMA predicted cognitive decline, but folate did not. A doubling in holoTC concentrations (from 50 to 100 pmol/L) was associated with a 30% slower rate of cognitive decline, whereas a doubling in tHcy (from 10 to 20 mumol/L) or MMA (from 0.25 to 0.50 mumol/L) was associated with a greater than 50% tendency toward more rapid cognitive decline. After adjustment for all vitamin markers simultaneously, the associations of cognitive decline with holoTC and MMA remained significant. This led researchers to conclude that low vitamin B12 status could initiate more rapid cognitive decline. Randomized trials, however, are required to determine the relevance of vitamin B12 supplementation for prevention of dementia.
Source: Am J Clin Nutr, November 2007;86(5):1384-91.
Research:
Elevated total homocysteine (tHcy) concentrations have been associated with cognitive impairment, but it is unclear whether low vitamin B12 or folate status is responsible for cognitive decline. So researchers decided to examine the associations of cognitive decline with vitamin B12 and folate status in a longitudinal cohort study performed from 1993 to 2003 in Oxford, U.K. Cognitive function was assessed with the Mini-Mental State Examination on at least three occasions during 10 years and related to serum concentrations of vitamin B12, holotranscobalamin (holoTC), tHcy, methylmalonic acid (MMA), and folate with the use of linear mixed models in 1648 participants who provided blood in 1995.
Results: Cognitive function declined abruptly at younger ages in some participants but remained intact in others until very old age. In multivariate regression analyses after adjustment for established risk factors, concentrations of holoTC (a marker of reduced vitamin B12 status), tHcy, and MMA predicted cognitive decline, but folate did not. A doubling in holoTC concentrations (from 50 to 100 pmol/L) was associated with a 30% slower rate of cognitive decline, whereas a doubling in tHcy (from 10 to 20 mumol/L) or MMA (from 0.25 to 0.50 mumol/L) was associated with a greater than 50% tendency toward more rapid cognitive decline. After adjustment for all vitamin markers simultaneously, the associations of cognitive decline with holoTC and MMA remained significant. This led researchers to conclude that low vitamin B12 status could initiate more rapid cognitive decline. Randomized trials, however, are required to determine the relevance of vitamin B12 supplementation for prevention of dementia.