Markers of vitamin B12 status, but not B12 levels themselves, were associated with lower scores on the cognitive tests and smaller total brain volume, researchers from the Rush University Medical Center in Chicago report in Neurology.
"Our findings definitely deserve further examination," said the study’s lead author Christine Tangney, PhD.
"It's too early to say whether increasing vitamin B12 levels in older people through diet or supplements could prevent these problems, but it is an interesting question to explore.”
Building the B12-brain link
This is not the first report of potential benefits of B12 on brain shrinkage. In 2008, researchers from the University of Oxford reported that people with higher blood levels of the vitamin were six times less likely to experience brain shrinkage compared with people with lower vitamin levels (Neurology, Volume 71, Pages 826-832).
Vitamin B12, also known as cobalamin, is only found in food of animal origin, including meat, milk and eggs. The recommended daily intake of vitamin B12 in Europe is 2.5 micrograms.
For the Chicago study blood samples were taken from 121 people aged over 65. Four and a half years after the blood sample collection, the participants had their brain scans
MRI scans were performed about four and half years later in order to measure total brain volume and look for other signs of brain damage.
“Concentrations of all vitamin B12-related markers, but not serum vitamin B12 itself, were associated with global cognitive function and with total brain volume,” report the researchers.
Markers of B12 status, like methylmalonate, cystathionine, and 2-methylcitrate were associated with poorer episodic memory, while homocysteine was associated with decreased total brain volume.
“Our findings lend support for the contention that poor vitamin B12 status is a risk factor for brain atrophy and possibly white matter hyperintensity volume (WMHV) which in turn may contribute to cognitive impairment,” wrote the researchers.
September 2011, Volume 77, Issue 13, Pages 1276-1282
“Vitamin B12, Cognition, And Brain Mri Measures: A Cross-Sectional Examination” Authors: C.C. Tangney, N.T. Aggarwal, H. Li, R.S. Wilson, C. DeCarli, D.A. Evans, M.C. Morris