A combination of high levels of homocysteine and low levels of vitamin B12 is a significant risk factor for Alzheimer's disease among African Americans, according to a paper presented today at the International Conference on Alzheimer's Disease and Related Disorders in Stockholm, Sweden.
Floyd Willis and colleagues at the Mayo Clinic in Florida conducted a study to evaluate the association between homocysteine, B12 and folic acid levels in African Americans with Alzheimer's disease.
They also wanted to assess whether the US Food & Drug Administration's (FDA) 1998 mandated increase in folic acid enrichment of grain had led to any increase of the folate in the blood of these individuals.
The Mayo Clinic researchers collected blood samples from 256 African Americans who showed no signs of cognitive impairment and 58 African Americans who had a clinical diagnosis of Alzheimer's disease. All study participants were over the age of 50.
When comparing the two groups, the researchers found 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.
When the blood samples were evaluated based on the date on which they were collected (before or after 1 January 1998, the date of the increase in folic acid fortification for commercial grain), the researchers found that both groups had significantly higher levels of folic acid in their blood after the ruling passed into law.
Dr Willis said that his research suggested that high levels of homocysteine and low levels of B12 were a risk factor for Alzheimer's disease in African Americans. However, the documented increase in folic acid levels following the decision to fortify grain should lead to a reduction in the incidence of vascular and neurodegenerative disease because of higher blood folate levels.
High levels of homocysteine have also been linked to damage of the arteries, which may increase an individual's risk of heart attack, stroke or other cardiovascular problems.
Abstracts of this and other studies presented at this week's conference can be found on the website.