B12 and the Brain

The vital vitamin might mean everything when it comes to brain health.

Posted Mar 03, 2016

Vitamin B12 is essential to brain health. As a psychiatrist, it is one of the few tests I run routinely,  and one of the few procedures I do is to give someone a vitamin B12 shot when levels run low. Like many things in biochemistry, however, sometimes the more we learn about a vitamin and the brain, the less we realize we actually know. B12 is no exception, as a recent study from PLOSone brings into stark review. 

It has long been known that B12 is vital for nerves to work properly, and it is only found in animal sources of food, not in plants. While it is made by our gut bacteria, it can only be absorbed in combination with something called intrinsic factor at the upper part of our intestines, so the B12 made in our colon by our gut bacteria is not metabolically useful. Traditional symptoms of B12 deficiency include a certain type of anemia where red blood cells are larger than they should be and signs of nerve death like numbness and tingling in the fingers and toes. However, its become clear that other symptoms of B12 deficiency can precede these classic medical findings, including depression and anxiety. That’s why I check new patients for B12 deficiency and prescribe B12 if the level is even marginally low. It’s also why I think entirely plant-based (vegan) diets are not the best for brain health, but that a reasonable amount of animal based foods are key to nominal levels of B12.

Wikimedia Commons
Source: Wikimedia Commons

A new study from PLOSone pulls out everything we know and don’t know about B12 and the brain and raises a million questions…in other words, the best sort of study. The design was simple, they took post-mortem brains from all sorts of ages from people without diagnoses and from autistic and schizophrenic samples. Brain measures of active forms of vitamin B12 were measured (one of them being methylB12). Of special interest is that brain levels of B12 do not necessarily match up with blood levels of B12. That means the serum test I order routinely to test B12 levels may not tell me about B12 levels in the brain. In any event, brain levels of methylB12 (an active form of B12) plummet with age from 20 year-olds to 60 year olds. Also, methylB12 levels in those diagnosed with autism or schizophrenia were 1/3 those of age-matched controls, meaning B12 just wasn’t as active in the brain of those patients.

Does that mean B12 supplementation could prevent autism or schizophrenia? Not so fast… correlation does not mean causation. But that pithy phrase doesn’t really encapsulate what is going on here. Chronic neuron-degenerating diseases such as autism, schizophrenia, and dementia are far more complicated than that and seem to have a lot to do with local inflammation. Overall oxidative stress (meaning the metabolic stress that comes from just having the mitochondria pump out energy for all the things we need energy for) increases with inflammation, and our ability to recover decreases with inflammation. Balancing stress and recovery is the real key to both total health and mental health. Understanding how our brains recover is key to maximizing mental health and the recovery from (or prevention of) devastating illnesses like autism spectrum disorder.

Would it hurt to supply those diagnosed with autism or schizophrenia with methylB12? It's cheap to get online, so the answer is no, probably not at all. Will it help? Not really clear. The overall picture seems to point to genetic and environmental issues with oxidative stress and glutathione, meaning maximizing B12 (particularly methylB12) and other agents helpful with oxidative stress such as NAC might be beneficial. NAC and methylB12 probably won’t hurt, either. 

I hope the overall result of this paper is to get folks to read into methylation, B12, oxidative stress, and psychiatric disease. The complexities are profound, but the benefit from some inexpensive supplements could be very real. We need more research, always, and more folks willing to talk about their experience with methylB12 and other nutrigenomic interventions. Besides that, there’s a lot to discover why B12 levels are so low in the brain when the serum levels are probably fine. Anyone interested in aging and longevity will have ears tuned to this paper and the results of subsequent research.

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