Researchers from the Nova South-Eastern University made the connection when they analysed brain tissue taken from healthy donors and from people who had suffered from autism or schizophrenia when they were alive.
Similar low levels are found in the brains of older people aged from 61 to 80, who typically have amounts that are three times less than in healthy younger people, but researchers believe this is natural, and doesn’t necessarily mean the person will develop dementia or Alzheimer’s.
An active form of B12, known as methylcobalamin, supports normal brain development by controlling a process known as epigenetic regulation of gene expression.
Autism and schizophrenia are associated with oxidative stress, when the body is unable to counter the spread of free radicals, and this can deplete levels of B12.
Researchers think that B12 supplements and antioxidants such as glutathione can help prevent oxidative stress, which may, in turn, stop the depletion of the vitamin.