B12 deficiency can affect your Eyesight

Julia found her eyesight going as her eyes refused to focus on the same things as each other.  She's been for all sorts of tests and treatment, but now that she's on B12 replacement therapy she's starting to see an improvement

Vitamin B12 (cobalamin as methyl-cobalamin or adenosylcobalamin) is used in the body for DNA reading (switching genes on and off, protein synthesis, cell multiplication), for myelination of nerve cells (which affects both what you feel and how your muscles work), for cell membrane integrity (which amongst other things affects how your immune system works and deficiency of this vitamin can cause autoimmune diseases), for chemical manufacture via cell membrane glandules (for example, the production of hormones, and the production of HCl and proteases in the stomach, the villi in the intestine, etc), and energy production in the mitochondria (and at the same time, removing the low mood chemical homocysteine).

What has this to do with eyes?

We’ve had a number of people come in with droopy eyelid and with eyes that won’t point in the right direction, won’t focus, etc.  We send them to the eye specialists who can do nothing and suggest eye patches, or just prepare to certify them blind. But a serum B12 test (this is one of the symptoms that, along with a cluster of others, is an indicator for B12 deficiency) reveals that the serum B12 is below normal, and we start them on B12 replacement therapy. One example is Julia http://b12d.org/content/eyesight_and_b12 who has only just started on Vitamin B12 at the time of the documentary, and already says she finds the eye patch (the misty bit on her glasses) is uncomfortable and she can align both eyes to the same object within a few days of starting treatment.

Why does this work?

  1. 1- the optic nerve is a mass of nerves which all need myelin to avoid confusing the signals, so the demyelination which is perhaps the most widely documented feature of B12 deficiency affects this dramatically
  2. 2- the eyes are surrounded by muscles to orient them and to focus.If the motor control is going,then the eyes can’t point right.
  3. 3- the nerves in the visual cortex also need myelin to process and overlay the complex images coming from each eye independently, and make them make sense together (the human brain is programmed to see in stereo, not to look at two images as though they were totally independent).

What should you do?

B12 is a water-soluble vitamin, like vitamin C, so it doesn’t last long in the body before it is either used up or flushed out in the urine (though see entero-hepatic circulation for how the body retains some – I presented Kevin Byrne’s paper on this at the Pernicious Anaemia Society’s annual conference a couple of weeks ago but I still have to put it into a form for diplay on the web).Therefore you need a steady supply in the food to keep healthy. And some people can’t absorb it from the food and need injections.

Vitamin B12 is also very cheap – it is used by vets, by farmers, and funnily enough by racehorse and racing greyhound owners to boost the performance of their animals.  People in USA even use it for weight loss – it doesn’t help you lose weight, but it gives you the enthusiasm to follow through with your exercise programme which does make you lose weight.