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Study: Vitamin B12 levels low in brains affected by autism or schizophrenia

Decrease may stem from oxidative stress and cause some autism symptoms, researchers speculate in study made possible by postmortem brain donation
January 25, 2016


A new report describes unusually low levels of vitamin B12 in the brains of people affected by autism or schizophrenia. The study also found that levels of the vitamin decrease with age regardless of whether a person has a neurological condition.

The open-access paper appears today in the journal PLOS One.

The researchers speculate that the abnormally low B12 levels seen in brains affected by autism or schizophrenia might result from oxidative stress – a harmful inflammatory condition. Previous studies have documented signs of oxidative stress in the brains of some people affected by either condition.

"The large deficits of brain B12 from individuals with autism and schizophrenia could help explain why patients suffering from these disorders experience neurological and neuropsychiatric symptoms," says study leader Richard Deth, of Nova Southeastern University, in Fort Lauderdale, Florida. "These are particularly significant findings because the differences we found in brain B12 with aging, autism and schizophrenia are not seen in the blood, which is where B12 levels are usually measured."

Deth and his co-authors call for additional research to explore whether the use of supplemental methyl B12 and antioxidants could help prevent oxidative stress and ease symptoms of these conditions.

Research made possible by postmortem brain donations
The study involved analysis of tissue from 64 postmortem brain donations. These included donations made to Autism BrainNet, an initiative supported by Autism Speaks and the Simons Foundation for Autism Research.

The researchers found that, overall, levels of B12 in the brain tissue from children with autism were three times lower than the levels in brain tissue from children unaffected by the condition. In fact, the average B12 brain levels for the children with autism was close to that of brain tissue from unaffected adults in their 50s. This pattern of lower-than-typical B12 levels persisted across the lifespan in the brain tissue from donors affected by either autism or schizophrenia. 

B12 and brain development
An active form of B12 called methylcobalamin, or methyl B12, supports healthy brain development through a process known as epigenetic regulation of gene expression, Deth says. (For more on epigenetics and brain development, see “What is epigenetics, and what does it have to do with autism?”) Lowered levels of methyl B12 in the brain could adversely affect early brain development and could disrupt learning and memory later in life, he proposes.

Read the full article –"Decreased brain levels of vitamin B12 in aging, autism and schizophrenia" – here. The study received financial support from the Autism Research Institute.

Learn more about the importance of postmortem brain donation for autism research – and learn how you and your family can participate – at and

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