MONDAY, April 5, 2004 (HealthDayNews) -- Low levels of vitamin B12 are associated with much worse scores on memory tests by older people with a genotype that puts them at high risk for Alzheimer's disease.
That's according to a study in the April issue of Neuropsychology.
The genotype, apolipoprotein E Type 4 allele, is carried by about 15 percent of people and is a risk factor for dementia. Research indicates that nearly one out of four carriers with one copy of the 4 allele and nearly half of people carrying two copies of the 4 allele will develop Alzheimer's disease.
Scientists also know that low levels of two B vitamins -- B12 and folate -- are linked to diminished memory and increased risk for Alzheimer's disease.
But few studies have examined the 4 allele genotype and nutrition together to see how they affect cognition.
This Swedish-British study included 167 healthy people, average age 83. Each of the participants had their blood checked for vitamin levels and genotype. They then completed a series of memory tests.
The study found the combination of low B12 levels and the 4 allele genotype was significantly associated with poorer memory. The study authors suggest people with the 4 allele genotype may get greater cognitive benefits from B12 and folate supplements.
"Supplement treatment is relatively inexpensive and may be required as part of preventive health regimes for older persons," the authors write.
More information
The U.S. National Institutes of Health has more about Alzheimer's disease.
