NEW YORK (Reuters Health) - A variant of a lipid gene called APOE4 is known to increase the chances of a person developing Alzheimer's disease. A Swedish study has now shown that carriers of this gene are more vulnerable to the effects of low vitamin B12 levels on mental function in old age.
Among healthy
individuals over age 75, APOE4 carriers have more memory lapses when
vitamin B12 falls below normal levels, according to the study
conducted at the Karolinska Institute in Stockholm.Dr. David Bunce, of the University of London, and colleagues note in the journal Neuropsychology that low levels of B vitamins have been associated with decreases in mental function.
To further investigate, Bunce's team determined the APOE4 status of 167 individuals age 75 and older and performed a range of cognitive tests. Among the subjects classified as APOE4-positive, 28 had low B12 levels and 21 did not. In the non-APOE4 group, 54 had low B12 levels and 64 had normal levels.
In the most demanding test, participants were presented with a list of 12 unrelated nouns, at a rate of one word every 2 seconds. They were immediately given 2 minutes to recall the words.
In the APOE4-positive group, average scores for this test were 3.68 for those with low B12 and 6.48 for those with normal levels. Corresponding scores in the non-APOE4 group were 4.78 and 5.32. Analysis showed that recall performance was significantly lower in the low-B12, APOE4-positive group.
The investigators also found that low folate levels had a similar effect, although it was not as strong.
They conclude, "There is good reason to consider inclusion of vitamin B12 and folate supplements as part of preventive health regimens for older persons," especially APOE4 carriers.
SOURCE: Neuropsychology, April 2004