Vitamin B12


Vitamin B12, or cobalamin, is a water soluble vitamin and cannot be made in the body and therefore is acquired purely from diet. It has a range functions in the body, including fatty acid and amino acid metabolism, DNA synthesis, the maturation of new red blood cells and in the synthesis of myelin - an important component in nerve cells that ensures quick and reliable signal transmission1.

You may have heard that vitamin B12 is only found in animal products, but this is slightly misleading. The only organisms capable of producing vitamin B12 are specific bacteria and archaea species, living in soil. Animals that eat the vegetation that grow in this soil take up these B12 producing species, which then live in the animal’s gut and continue producing B12. This is why animal products are a good source of B12. Few vegetables are shown to be a source of B12. Vegetarians and vegans should increase their intake of B12 via fortified foods or supplements.

Why do you need it?

A severe lack of vitamin B12 causes many serious side effects, causing damage to the brain and nervous system, which very little people have to worry about in developed countries due to our access to meat and fortified foods2. However, less significant deficiencies can be more common that most people think, with symptoms including anaemia, lethargy, headaches, difficulty walking and poor memory. Studies have shown that around 14-16% of 20-59 year olds and 20% of over 60 year olds are marginally deficient in B12, and would benefit from supplementation3,4. The most common reasons for deficiency are inadequate intake and inadequate absorption4.


50 g of clams - 2060% of your daily intake

100 g of beef liver - 779% of your daily intake

100 g of canned sardines - 371% of your daily intake

250 g of steak - 229% of your daily intake

salmon fillet -  160% of your daily intake

Vegan sources (fortified):

2 tbsp of nutritional yeast - up to 130% of your daily intake

200 ml of Alpro soya drink - 32% of your daily intake

1 serving (28 g) corn flakes - 63% of your daily intake

Which potency is right for me?

If you follow a plant-based diet and don’t eat many fortified foods, or have trouble absorbing B12, the 1000 ug dose may be right for you. If you’re none of the above but looking for an energy boost and think B12 may be the answer for you, try the 500 ug. If in any doubt, seek professional medical advice.

  1. Office of Dietary Supplements Factsheet, 2019
  2. Oregon State University Micronutrient Information Center, 2015
  3. Harvard Medical School - Vitamin B12 deficiency can be harmful, sneaky. (Skerrett, 2013)
  4. How common is vitamin B-12 deficiency? (Allen, 2009)

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