What is vitamin B12 and what does it do?
Our understanding of vitamin B12 may have changed over the years, but our bodies’ need for this multi-tasking vitamin hasn’t.
In fact, every cell in the human body uses vitamin B12 to some degree in its function.
Vitamin B12 is needed for:
- red blood cell formation
- a strong immune system
- the nervous system
- cell production2
We gradually rid our bodies of vitamin B12 throughout each day whenever we visit the toilet, so we have to ensure we’re replacing it consistently.
Why you might need extra vitamin B12?
Running low on vitamin B12 can impact your health, so it’s important to know if you might need a little extra. A lack of vitamin B12 can impact your health.
Low levels can cause tiredness and a lack of energy.
Severely low levels can lead to vitamin B12 deficiency anaemia, a condition which can lead to:
- muscle weakness
- pins and needles
- a sore tongue
- mouth ulcers
- confusion and impaired judgement
- disturbed vision3
Vegetarians and vegans are at risk of running low on vitamin B12, as dietary sources of vitamin B12 are exclusively from animal products. Luckily, eating vitamin B12-fortified food and taking a B12 supplement may address this.In the UK and other developed countries, malnutrition is rare. However, in other parts of the world, vitamin B12 deficiency is common, especially in countries with a high vegetarian population.4
Following a highly restrictive diet, such as one designed for rapid weight loss, may also find themselves lacking the vital vitamin B12 they need to stay healthy.Older adults are also more likely to experience low levels of vitamin B12, with around 1 in 10 people aged 75 or over and 1 in 20 people aged 65 – 74 affected.5 Older people tend to produce less stomach acid, which is needed to absorb vitamin B12 from food.
For a severe deficiency, vitamin B12 injections might be prescribed by a doctor.
Sources of vitamin B12There are actually 8 different essential vitamins which make up vitamin B6
- thiamin (vitamin B1)
- riboflavin (vitamin B2)
- niacin (vitamin B3)
- pantothenic acid
- vitamin B6
- biotin (vitamin B7)
- folate and folic acid
- vitamin B12
They can be found all together in a vitamin B complex. Whole grains, meat and legumes are sources of vitamin B in all its forms.
The most abundant and bioavailable dietary sources of vitamin B include:
- dairy products like eggs and yoghurt
Vegans might struggle to get enough vitamin B12 from dietary sources, as plants and fungi don’t contain it. The vegan foods that do contain it include
- nutritional yeast
- some fortified soya products
- breakfast cereals are often fortified with vitamins and iron and are good sources of B vitamins, including vitamin B12
If you’re vegan, consider taking a B12 supplement to ensure you’re getting the vitamin B12 you need.
How much vitamin B12 do I need?Adults need about 1.5 micrograms vitamin B12 per day.7
Why don’t we get as much vitamin B12 as our early ancestors?
It’s not a myth – our ancestors really did get more vitamin B12 than we do.
Despite huge advances in nutrition knowledge over the centuries, the natural levels of vitamin B12 available in nature have dropped.
Vitamin B12 is produced by the fermentation of microbes found naturally in soil. To do this, the soil must also contain the trace mineral cobalt.
Hundreds of years ago, before intensive farming, soil was rich in the microbes and cobalt required to produce vitamin B12. Eating vegetables fresh from the field, for instance, would provide you with it, as would drinking from a mountain stream.Now, even farm animals take b12 supplements, as due to agricultural conditions they don’t always get the exposure to soil they once did, and if they do, that soil is often deficient in the cobalt needed for the production of vitamin B12.8
Last updated: 18 June 2020
- Vitamin B12 deficiency is endemic in Indian population: A perspective from North India
Singla Rajiv, Garg Arpan, Surana Vineet, Aggarwal Sameer, Gupta Geetu, Singla Sweta 2019 Volume: 23 Issue Number: 2 Page: 211-2145 https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/ 6 https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-b/ 7 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/618167/government_dietary_recommendations.pdf 8 https://www.zoetis.com.au/_locale-assets/faq/cobaltdeficient.pdf