You need vitamin B12 to form DNA, make healthy blood cells and keep nerves working properly. A deficiency of vitamin B12 will ultimately lead to anaemia, peripheral neuropathy, and cognitive impairment.
Conditions associated with a B12 deficiency are impairments in nutrient absorption, autoimmune pernicious anaemia, chronic pancreatitis, Celiac and Crohn's disease.
It has been found that both B12 as well as folate (B9) levels tend to be lower in depressed individuals (Coppen & Bolander-Gouaille, 2005). Primary symptoms of deficiency are severe tiredness, lethargy, poor short term memory and reduced training performance.
How much you need on a daily basis depends on how deficient you are. You can assess this easily using one of our Core Ten Blood Panel Tests. You are generally seen as deficient if you are below 250pmol/l. If you are significantly deficient, which a lot of people are, generally you should aim to get 1,000mcg (1mg) of B12. You can do this via supplementation, or better still, you can consume the foods within the infographic above on a daily basis.
These are the foods highest in vitamin B12. Im probably right in assuming that you don't have these foods on a regular basis, if not at all! If you're not eating fish and organ meat on a regular basis then you should reconsider if you are at all conscious about your health, well-being and performance.
Fortunately, unlike other water soluble vitamins, your liver can store a reserve of B12, however this may not last for long if your diet is severely low. If you increase your dietary intake using the info-graphic above, your symptoms may subside and you can reduce your intake of such foods provided they play a regular role in your diet.