Researchers at the Mayo Clinic in Jacksonville, Florida, have found that African Americans with Alzheimer's disease have higher high levels of the blood compound homocysteine and lower levels of vitamin B12 than those who show no signs of impairment.

Reporting at the 8th International Conference on Alzheimer's Disease and Related Disorders in Stockholm, the researchers said they collected blood samples 314 African Americans over the age of 50 to evaluate the association between homocysteine, B12 and folic acid and Alzheimer's.

The researchers reported that homocysteine levels were significantly higher in the individuals with Alzheimer's disease and levels of B12 were significantly lower. The levels of folic acid, however, were not significantly different between the groups.

High levels of homocysteine also have been linked to damage of the arteries, which may increase an individual's risk of heart attack, stroke or other cardiovascular problem, the researchers added.

Other sources: International Conference on Alzheimer's Disease