Amino Acid (Homocysteine) linked to Alzheimer's

Heard of homocysteine?                                      (back)

If not, you will soon, health experts say. New research is finding homocysteine (ho-mo-SIS-teen), an amino acid, may play a role in the onset of dementia. The good news is that vitamins B6, B12 and folic acid may reduce the levels of homocysteine in the blood, says Dr. James Toole, a professor of neurology and public health science at Wake Forest University School of Medicine.

He believes people will soon have their homocysteine levels checked as routinely as cholesterol. "Researchers have found high homocysteine levels are associated with Alzheimer's disease and brain atrophy," Toole says. "This is big time news."

The latest research appears in the May 29 issue of the journal Neurology. Two studies show that people with elevated levels of homocysteine are more likely to have brain atrophy and vascular disease, which are related to the development of dementia. Alzheimer's disease is one form of dementia. In one of the studies, researchers tested the blood homocysteine levels of 36 healthy, elderly people, and then used brain scans to measure the amount of brain atrophy, or loss of brain cells and volume. The study found those who had the highest levels of brain atrophy were twice as likely to have high homocysteine levels as those with less atrophy. Previous research has shown mild elevations of homocysteine in about 5 percent to 7 percent of the population, says Toole, who wrote an editorial in the journal on the research.

In the second study, researchers did similar tests on 43 people with Alzheimer's and 37 healthy people. They found people with high homocysteine levels were 10 times more likely to have vascular disease. The study also found Alzheimer's patients were 12 times more likely to have low levels of vitamin B6 than the healthy people. "The finding will need to be confirmed by other studies, but it is interesting," says Joshua W. Miller, author of the second study and an assistant professor of medical pathology at University of California, Davis Medical Center. "Vitamin B6 has been shown to play a role in brain function and memory, so it's possible that taking B6 supplements could help Alzheimer's patients."

Earlier studies have linked Alzheimer's and elevated homocysteine, Miller says. His research didn't find that same correlation, but in studies that did find a link, the dementia attributed to Alzheimer's could be made worse by vascular disease. Homocysteine is an amino acid that's formed when the body breaks down methionine, which is found in protein-rich foods, Miller says. Previous research has found folic acid counteracts the homocysteine by converting it into a non-toxic form. However, in people who don't have enough folic acid, the level of homocysteine rises and becomes toxic.

Homocysteine is suspected of irritating the lining of blood vessels, accelerating atherosclerosis and contributing to blockages, Toole says. If folic acid - also known as folate - keeps homocysteine down, shouldn't everyone take a supplement? Not exactly, Toole says. Folic acid deficiencies have been linked to certain birth defects. In 1998, the U.S. Food and Drug Administration mandated that grain producers fortify their product with folic acid. That means that bread, cereals and pastas - anything made with grain - contain added folic acid, Toole says. So, it's very possible you get plenty of folic acid by eating a balanced diet.

Also, no one has established the optimum level of folic acid people need. So theoretically, you could take too much, Toole says. Vitamins B12 and B6 may also lower homocysteine levels, Miller says. In addition to grains, citrus fruits, tomatoes and vegetables are good sources of folic acid. You can get vitamin B6 from meat, poultry, fish, fruits, vegetables and grain products. Major sources of B12 include meat, poultry, fish and milk, Toole says. Toole does recommend that everyone over age 60, or people at high risk of heart and vascular disease, ask to have their homocysteine levels checked by their doctor. This can be done with a simple blood test.

What To Do: Read more about homocysteine at familydoctor.org. To learn more about the possible link between homocysteine levels and Alzheimer's, see this National Institutes of Health report. Copyright © 2002 ScoutNews, LLC. All rights reserved.                                                                                                      Top