Feb. 28, 2003 -- High levels of a substance in the blood called homocysteine tops the list of potentially new risk factors for heart disease, stroke, and now dementia. A new study suggests that high homocysteine levels are linked with mental declines associated with Alzheimer's disease in elderly people.
Elevated levels of homocysteine is an indication of inadequate folate and vitamin B-12 in the diet, writes lead author Giovanni Ravaglia, a researcher with University Hospital S. Orsola-Malpighi in Bologna, Italy. His paper appears in the March American Journal of Clinical Nutrition.
In their study, researchers tested the blood of 650 elderly Italians -- with no signs of dementia or Alzheimer's disease -- looking at levels of folate and vitamin B-12. They also asked about other dietary factors such as coffee, wine, and liquor consumption and about physical activity.
Researchers found that those with lower scores on tests of thinking ability had high levels of homocysteine. They found the same association even after taking into account other risk factors for dementia, including age, socioeconomic status, and risk factors for heart disease.
Some study participants may have early or very mild cognitive impairment, especially those whose scores on the tests were low. People with early dementia often perform within normal limits on cognitive tests, Ravaglia writes.
Though nutritional deficiencies can be the cause, some medications like the seizure drug Dilantin can elevate homocysteine levels in the blood. Kidney disease, alcohol use, and too little physical activity can also elevate homocysteine.