23/05/2026
Normal Vitamin B12 Ranges May Miss Early Brain Injury in Seniors
Current medical guidelines suggest certain vitamin B12 blood levels are adequate for older adults, but new research suggests these standards might miss subtle brain injury. Scientists studied 231 healthy seniors and found that even within the normal range, lower levels of active B12 were linked to slower brain processing speeds, delayed nerve signals in the visual system, and larger areas of white matter damage visible on brain scans. Unexpectedly, high levels of inactive B12 also correlated with elevated Tau protein, a marker associated with neurodegeneration. These findings indicate that the current definition of sufficient B12 may not protect against neurological changes in aging. The results challenge doctors to reconsider optimal nutritional thresholds for preserving brain health in later life.