Last week's column reported that people with Alzheimer's disease have higher levels of homocysteine in their blood than people without Alzheimer's disease.
These neurological studies confirm epidemiological studies that show high homocysteine levels to be correlated with Alzheimer's and cognitive impairment. Among these epidemiological studies is a study by Sudha Seshadri and colleagues in the February 14, 2002, New England Journal of Medicine which found that a plasma homocysteine level greater than 14 micromoles per liter caused the risk of Alzheimer's disease to double. (Homocysteine levels should be less than 10 and ideally less than 7.)
Another study by Pierluigi Quadri together with other researchers found high homocysteine levels in subjects with mild cognitive impairment, often a precursor to Alzheimer's disease. The average homocysteine level in these subjects was 14.6. The study also found that those subjects with the lowest levels of folate (the vitamin folic acid) had a greater risk of Alzheimer's disease compared to those with the highest levels of folate.
Two of the most recent studies on homocysteine and Alzheimer's disease have come to similar conclusions. Giovanni Ravaglia and associates published a study in the September 2005 issue of the American Journal of Clinical Nutrition that found elevated plasma homocysteine and low serum folate concentrations to be independent predictors of the development of dementia and Alzheimer's disease. In the same issue of this journal, Katherine L. Tucker and her colleagues found that high homocysteine levels and low B vitamin concentrations (specifically, folate and vitamins B-6 and B-12) predicted cognitive decline. These B vitamins lower homocysteine levels.
How To Lower Your Risk of Alzheimer's
The take home message of these studies is to lower homocysteine and increase B vitamins. Fortunately, this is not difficult to do. By increasing B vitamins, we also decrease homocysteine. Homocysteine is controlled by these three B vitamins - folic acid, B-6 and B-12. They can be optimized by diet and, if necessary, by supplementation. A diet of fresh, whole, unprocessed food is rich in all three of these vitamins. Folic acid is found in green leafy vegetables like spinach, dark greens, asparagus and many other vegetables and fruits. B-6 is also found in fresh vegetables and fruit as well as fish, poultry and meat. B-12 is found only in food of animal origin, but these foods must be fresh as opposed to processed foods such as bacon, hot dogs, and cold cuts. If diet alone does not lower homocysteine levels, then supplementation may be necessary, but supplementation can never substitute for a healthful diet. As its name implies, supplementation is in addition to, not in place of.
To find out your homocysteine level, ask your doctor for a blood test to determine what your level is. If it is not in the optimum range, a change in diet and supplementation with folic acid, B-6 and B-12 can bring it down to the normal range.
Mary Lou Williams, M. Ed., is a lecturer and writer in the field of nutrition. She welcomes inquiries. She can be reached at 267-6480.