A new Swedish study has found that a deficiency of vitamin B12 causes the symptoms of Alzheimer’s disease, such as lapses in memory, to worsen.
The study, published in the April issue of Neuropsychology, follows several notable studies of B12 that have shown the vitamin influences mental function and mood.
More memory lapses with low B12
The researchers studied the influence of vitamin B12 on the gene called APOE4—a gene whose presence is known to increase the chances of developing Alzheimer's disease. The study’s preliminary tests found that among healthy individuals over age 75, APOE4 carriers have more memory lapses when vitamin B12 falls below normal levels.
The scientists continued their research, ascertaining the APOE4 status of 167 subjects age 75 and older. Among those 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. Researchers then performed a range of cognitive tests, including a series of challenging recall tests.
Good reason to include B12 for prevention
In the APOE4-positive group, average scores for these tests were up to 50% lower for subjects with low B12. Corresponding scores in the non-APOE4 group were 20% lower for those with low B12. It was clear that recall performance was significantly lower in the low-B12, APOE4-positive group. The study also found that low folate levels had a similar effect, although to a lesser extent.
The scientists recommended inclusion of vitamin B12 and folate supplements as part of preventive health regimens for older patients, especially APOE4 carriers.
1. D. Bunce et al., “Utilization of Cognitive Support in Episodic Free Recall as a Function of Apolipoprotein E and Vitamin B12 or Folate Among Adults Aged 75 Years and Older,” Neuropsychology, 2004, Vol. 18, No. 2, 362–370