LEXINGTON, KENTUCKY. Studies have shown that low concentrations of folic acid (folates) in the blood are associated with an increased risk of dementia and Alzheimer's disease (AD). Researchers at the University of Kentucky now report that low folate levels are directly associated with a high degree of atrophy of the cerebral cortex. Their study involved 30 nuns who had blood samples drawn and analyzed prior to their death between the ages of 78 and 101 years. Autopsies of the brains showed a clear negative association between folate levels and atrophy of the neocortex and this association was especially strong among the nuns who had been diagnosed with Alzheimer's disease. The average folate level in the nuns with significant AD was 45 nmol/L as compared to 61 nmol/L in the nuns without significant AD. It is interesting that the average blood levels of folate was 104 nmol/L in the nuns taking multivitamin pills as compared to only 36 nmol/L in those not taking supplements.
The researchers also found that the nuns with moderate to severe atherosclerosis in the arteries supplying the brain had an average blood folate level of only 34 nmol/L while those with minimal atherosclerosis had a level of 75 nmol/L. They conclude that a folate deficiency is associated with increased atrophy of the neocortex, particularly in patients with Alzheimer's disease.
Snowdon, David A., et al. Serum folate and the severity of atrophy of the neocortex in Alzheimer disease: findings from the Nun Study. American Journal of Clinical Nutrition, Vol. 71, April 2000, pp. 993-98
Weir, Donald G. and Molloy, Anne M. Microvascular disease and dementia in the elderly: are they related to hyperhomocysteinemia? American Journal of Clinical Nutrition, Vol. 71, April 2000, pp. 859-60 (editorial)