Studies show vitamin B12 can provide neurological protection, but what is recognized as a healthy amount may not actually be enough. Researchers at the University of California San Francisco found that the current recommendations for vitamin B12 consumption is not sufficient to ward off neurodegeneration in older adults.
Vitamin B12 is necessary for making DNA, red blood cells and nerve tissue. But if you don't get more than what is currently recommended then you may be at a greater risk for cognitive impairment, as were some of the volunteers in the study. The ones with lower concentrations of vitamin B12, even though there were in the normal range, showed signs of neurological and cognitive deficiency.
Those lower levels were associated with more damage to the nerve fibers that enable communication between areas of the brain. The changes in white matter were also associated with slower cognitive and visual processing speeds when compared to those with higher vitamin B12 levels.
That led researchers to conclude the recommended amount of B12 might need to be reconsidered.
"Previous studies that defined healthy amounts of B12 may have missed subtle functional manifestations of high or low levels that can affect people without causing overt symptoms," said senior author Ari J. Green, MD. "Revisiting the definition of B12 deficiency to incorporate functional biomarkers could lead to earlier intervention and prevention of cognitive decline."
The study consisted of 231 older adults with an average age of 71. They were generally healthy and showed no signs of dementia or mild cognitive impairment. Their average B12 amounts in blood samples were 414.8 pmol/L, which is well above the recommended minimum of 148 pmol/L.
Those with lower levels of B12 were found to have slower brain processing speed which is related to subtle cognitive decline. They also showed a slower response to visual stimuli. That was indicative of slower brain conductivity.
MRIs showed those with lower levels of vitamin B12 also had higher volumes of lesions associated with cognitive decline and dementia in their brain white matter.
"In addition to redefining B12 deficiency, clinicians should consider supplementation in older patients with neurological symptoms even if their levels are within normal limits," said researcher Alexandra Beaudry-Richard. "Ultimately, we need to invest in more research into the underlying biology of B12 insufficiency, since it may be a preventable cause of cognitive decline."