A new study by Vogiatzoglou in Neurology 2008, finds that low B12 levels are associated with cerebral atrophy.( 1 ) This is not surprising given the importance of B12 for nerve and brain cell function.
Cerebral Atrophy is Normal with Aging
It is well known that as we age, our brains gradually lose volume and shrink in a process called cerebral atrophy. Ask any radiologist who reads brains scans and they will agree that the older the patient, the more likely they will see enlarged cerebral ventricles and enlarged sulci (CSF spaces) indicating cerebral atrophy. This is loss of brain tissue (gray and white matter) with age. (See images below)
MRI Scan of Cerebral Atrophy Mid-Sag Slice
Left Image (normal) shows normal thickness corpus callosum and third ventricle size (red arrow) and enlarged pre-pontine cistern (green arrow). Right Image (atrophy) shows thinning of corpus callosum (red arrow), enlargement of third ventricle (red arrow), and enlargement of the pre pontine cistern (green arrow). Right image (atrophy) shows enlarged sulci, enlarged CSF spaces and obvious overall smaller size of brain.
Other Causes of Cerebral Atrophy
Other causes of cerebral atrophy are things like alcoholism which is toxic to the brain. Here is a more complete list of diseases and causes of cerebral atrophy.( 2 )
1) stroke and traumatic brain injury 2) Alzheimer’s disease, Pick’s disease, senile dementia, fronto-temporal dementia, and vascular dementia 3) cerebral palsy 4) Huntington’s disease, and other gene-linked, hereditary diseases 5) leukodystrophies, such as Krabbe disease, which destroy the myelin sheath that protects axons 6) mitochondrial encephalomyopathies, such as Kearns-Sayre syndrome 7) multiple sclerosis, which causes inflammation, myelin damage, and lesions in cerebral tissue 8) infectious diseases, such as encephalitis, neurosyphilis, 9) epilepsy 10) toxins
Now, we must add B12 deficiency to the above list.
Conclusion: Remember to take you B12 supplement every day as recommended by the 2005 revised USDA Dietary Guidelines for Americans, MyPyramid.
Vitamin B12 status and rate of brain volume loss in community-dwelling elderly A. Vogiatzoglou, MSc, H. Refsum, MD, PhD, C. Johnston, S. M. Smith, DPhil, K. M. Bradley, FRCR, FRCP, C. de Jager, PhD, M. M. Budge, MD and A. D. Smith, DPhil, FMedSci
Objectives: To investigate the relationship between markers of vitamin B12 status and brain volume loss per year over a 5-year period in an elderly population.
Methods: A prospective study of 107 community-dwelling volunteers aged 61 to 87 years without cognitive impairment at enrollment. Volunteers were assessed yearly by clinical examination, MRI scans, and cognitive tests. Blood was collected at baseline for measurement of plasma vitamin B12, transcobalamin (TC), holotranscobalamin (holoTC), methylmalonic acid (MMA), total homocysteine (tHcy), and serum folate.
Results: The decrease in brain volume was greater among those with lower vitamin B12 and holoTC levels and higher plasma tHcy and MMA levels at baseline. Linear regression analysis showed that associations with vitamin B12 and holoTC remained significant after adjustment for age, sex, creatinine, education, initial brain volume, cognitive test scores, systolic blood pressure, ApoE 4 status, tHcy, and folate. Using the upper (for the vitamins) or lower tertile (for the metabolites) as reference in logistic regression analysis and adjusting for the above covariates, vitamin B12 in the bottom tertile (<308 pmol/L) was associated with increased rate of brain volume loss (odds ratio 6.17, 95% CI 1.25–30.47). The association was similar for low levels of holoTC (<54 pmol/L) (odds ratio 5.99, 95% CI 1.21–29.81) and for low TC saturation. High levels of MMA or tHcy or low levels of folate were not associated with brain volume loss.
Conclusion: Low vitamin B12 status should be further investigated as a modifiable cause of brain atrophy and of likely subsequent cognitive impairment in the elderly.
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