What does it do?
Playing a key role in blood cell formation, B12 also aids iron absorption, and both tissue growth and nerve cell maintenance. It's particularly important for growth when we're young, and also plays a part in helping the body to produce red blood cells and in controlling the appetite.
What’s the story?
Perhaps the most unique of all the vitamins, B12 is the only molecule in the human body to contain cobalt, and is needed in only very small amounts as the body can store B12 more effectively than it can any other vitamin.
A pretty hefty vitamin in terms of the number of atoms it contains (a whopping 181 – by contrast vitamin C has only 20 atoms), it took scientists a long old time to figure out how to synthesise it themselves. Despite being isolated in 1948, it was only in 1973 that B12 could be successfully made in a lab.
B12 is a sort of ‘frenemy’ of folate (B9), where both rely on the other for activation. Folate needs B12 in order to convert folate in the diet into its active form. Similarly, the intriguing sounding ‘folate trap’ describes the situation whereby deficiencies of B12 and folate co-exist together, with folate masking B12 deficiencies.
B12 is made by bacteria, and so plant eating animals only manage to produce B12 thanks to the microflora in their guts. In humans B12 can only be found in animal sources, something vegans need to be aware of.
How much do I need?
Adult women and men aged 19 and beyond (including 50+ year olds) need 1.5 μg per day.
Where can I find it?
B12 is found mostly in animal based products, including meat, fish and dairy. Marmite is the best (and one of the only) source of B12 for vegans as it's rich in yeast, and any vegans should therefore consider taking B12 as a supplement or eat fortified cereal products as deficiency can lead to anaemia.
Any ideas for using those ingredients?
Marmite glazed nuts/coriander seared steak/tamarind pork/tuna and avocado poke/mackerel with black olives, capers and tomato/salmon and miso stir-fry/shakshuka/liver alla veneziana
References
British Dietetic Association (2014) Food Fact sheet - Vegetarian diets. Available here.
British Nutrition Foundation (2021) Nutrition Requirements. Available here.
Martyn, K. (2011) Nutrition: made incredibly easy. London, Lippincott Williams & Wilkins, chp. 6.
Price, C. (2016) The Vitamin Complex. London, Oneworld Publications, pp. 260 -1.