Vitamin B12 is best known for helping the body make DNA, red blood cells, and healthy nerve tissue. But research suggests that simply meeting the current minimum standard may not always be enough, especially for older adults. A UCSF led study found that healthy older people with lower vitamin B12 levels, even when those levels still fell within the accepted normal range, showed signs of subtle neurological and cognitive problems. The findings raise a provocative possibility: some people may be told their B12 status is fine while their brains are already showing early signs of strain. "Normal" B12 May Not Always Mean Optimal The study, published in Annals of Neurology , looked at older adults who did not have dementia or mild cognitive impairment. Even in this relatively healthy group, lower levels of active B12 were linked to slower thinking, slower visual processing, and more visible injury in the brain's white matter.…