The international research team led by Richard Deth, Ph.D., professor of pharmacology at Nova Southeastern University's (NSU) College of Pharmacy, analyzed tissue from otherwise healthy deceased donors along with tissue from donors who had autism or schizophrenia to make the comparisons.
"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." said Dr. Deth. "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."
The study also found healthy elderly people in the age range of 61-80 have about three times lower levels of total brain B12 than younger age groups, which is a result of normal aging. This normal decrease may help adjust brain metabolism to sustain its function across the lifespan.
An active form of B12 called methylcobalamin, or methyl B12, supports normal brain development by its control through a process known as epigenetic regulation of gene expression. Remarkably, the brain level of methyl B12 was found to be more than 10 times lower in healthy elderly people than in healthy younger people. A lower than normal level of methyl B12 in the brain could adversely affect neurodevelopment in younger years and could disrupt learning and memory later in life.
Both autism and schizophrenia are associated with oxidative stress, which also plays an important role in aging, and oxidative stress may underlie the decreased brain B12 levels observed in this study. The findings suggest the need for further research to determine if the use of supplemental methyl B12 and antioxidants like glutathione could help prevent oxidative stress and be useful in treating these conditions.
The research team consisted of Dr. Deth; Yiting Zhang (Northeastern University); Nathaniel Hodgson (Harvard University); Malav S. Trivedi (Nova Southeastern University); Hamid Abdolmaleky (Boston University); and Margot Fournier, Michel Cuenod and Kim Quang Do (Lausanne University, Switzerland).
Journal Reference:
- Yiting Zhang, Nathaniel W. Hodgson, Malav S. Trivedi, Hamid M. Abdolmaleky, Margot Fournier, Michel Cuenod, Kim Quang Do, Richard C. Deth. Decreased Brain Levels of Vitamin B12 in Aging, Autism and Schizophrenia. PLOS ONE, 2016; 11 (1): e0146797 DOI: 10.1371/journal.pone.0146797
Comment: B12 deficiency is far more common than most health care practitioners and the general public realize. One study suggests that 40 percent of people between the ages of 26 and 83 have plasma B12 levels in the low normal range - a range at which many experience neurological symptoms. It is possible that at least some of the symptoms we attribute to "normal" aging - such as memory loss, cognitive decline, decreased mobility are in part caused by B12 deficiency. As well as cognitive decline, many diseases may be caused by Vitamin B12 deficiency, including neurological disorders such as MS, cardiovascular disease, mental illness, learning and developmental disorders in children, autoimmune diseases and cancer.
The best dietary sources of B12 include meat, poultry fish and eggs, which is one reason why B12 deficiency is particularly common in vegetarians and vegans. The most recent studies using more sensitive techniques for detecting B12 deficiency have found that 68% of vegetarians and 83% of vegans are B12 deficient, compared to just 5% of omnivores.