Low levels of vitamin B12 are associated with poorer memory in older people with high risk for Alzheimer’s, according to a large Swedish study, thought to be one of the first to examine how the relationship between diet and genes can affect cognition in old age.The researchers found that in healthy people over the age of 75 who have the genotype associated with higher risk for Alzheimer’s, low levels of vitamin B12 were associated with significantly worse performance on memory tests. Scientists already knew of a genetic predisposition for Alzheimer’s disease, and that low levels of two B vitamins - B12 and folate - were also linked to problems. However, few had examined nutrition and genotype together relative to cognition.
