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sources of vitamin B12

Vitamin B12: benefits, uses & foods

23 Nov 2022 • 17 min read

Vitamin B12, also known as cobalamin, is a really important nutrient that plays a vital role in many bodily functions. As it is most commonly found in animal products, vegans and vegetarians might struggle to get enough of this essential vitamin.1,5 

Here, we’ll answer some of your most frequently asked questions about vitamin B12 so you can learn all about what vitamin
B12 does, how much you need, where to find it and who might need to supplement their diet.

What is vitamin B12?

Like all 8 B vitamins, vitamin B12 is needed to help your body convert food into energy. It’s also essential for other bodily processes like producing red blood cells and reducing tiredness.1

Vitamin B12 is water-soluble and it dissolves upon contact with the water in your body, so we need to make sure we consume enough of it every day. Our body can store a small amount of it in the liver which can last up to 4 years, but we still must get the right amount from our daily diet.2  It is only naturally found in animal products such as meat and dairy, so vegans and vegetarians are at risk of low intakes.3

Older people and those who don’t produce enough stomach acid to absorb B12 properly may also be at risk of a deficiency.4

What does vitamin B12 do?

Each B vitamin plays an important role in the body. Vitamin B12 is thought to be important for: 
  • Producing red blood cells 
  • Normal nervous system function
  • Supporting the immune system 
  • Maintaining healthy psychological function
  • Helping the body absorb folic acid 
  • Reducing fatigue 
  • Creating DNA during cell division 
Handpicked content: What is vitamin B12 and why is it important?

How much vitamin B12 do you need? 

All adults need 2.4mcg of vitamin B12 every day. You should be able to get this from eating a well-balanced diet, but you’re more at risk of a vitamin B12 deficiency if you’re vegan or vegetarian and don’t eat meat or animal products.

Breastfeeding mothers may need an extra 0.4mcg a day, particularly if they’re also vegetarian or vegan.6

Do children need vitamin B12?

Vitamin B12 is needed for healthy cell division, so it’s important for growing children:7 
  • 1-3 years old – 0.5mcg a day 
  • 4-6 years – 0.8mcg a day 
  • 7-10 years – 1mcg a day 
  • 11-14 years – 1.2mcg a day 
  • 15-18 years – 1.5mcg a day

What happens if I consume too much vitamin B12?

There’s no set upper limit for vitamin B12, but the NHS advises having no more than 2mcg a day.1,7 What foods contain vitamin B12? The best sources of vitamin B12 are animal-based products like meat, fish, milk, cheese, and eggs. You can also find B12 in some fortified cereals and plant milk, yeast extract and some soya products.2,6

The synthetic, manufactured form of vitamin B12 is called cyanocobalamin, which you may see in supplements.

Handpicked contentThe best sources of vitamin B

What are the symptoms of a vitamin B12 deficiency?

A vitamin B12 deficiency is most likely to affect vegetarians, vegans, and older people. Vegans and vegetarians are at risk because they don’t eat meat, while older people may not absorb vitamin B12 properly from their food due to declining levels of stomach acid.4

Low B12 symptoms include:4 
  • Fatigue/exhaustion 
  • Muscle weakness 
  • Vision impairment 
  • Pins and needles 
  • Sore tongue or mouth ulcers 
  • Poor memory 
  • Depression and anxiety

A lack of vitamin B12 can lead to megaloblastic anaemia, which is where your body produces fewer red blood cells, that are also larger than normal.

You can better understand your health and well-being with an at-home testing kit for vitamin B12. However, at-home tests shouldn’t replace seeing your doctor for any concerns, and they can’t give you a reliable diagnosis. So, for any concerns, you should always discuss your results with your GP - they can provide you with any help and advice you may need.

Handpicked content: How to test your B12 levels

Are there vitamin B12 supplements?

You can find vitamin B12 in a supplement format too, but it is important to check with a GP before adding one to your routine. They’ll be able to check and offer advice as to whether you need to take a supplement to support your B12 intake.

Vitamin B12 supplements are available as tablets, capsules, gummies, drops and sprays – so whatever your preference, there’s a vitamin B12 supplement out there to suit you.

Some fortified foods, like breakfast cereals and nutritional yeast, have vitamin B12 added to them to also support your daily intake – just make sure you stick to the recommended serving size!2

When should you take a vitamin B12 supplement?

If you’re following a plant-based diet, taking a vitamin B12 supplement can help support your intake and prevent a deficiency. Older people, or those taking medication to reduce the production of stomach acid, may need a B12 supplement to support absorption, but check with your GP first.9

Should children take a vitamin B12 supplement?

Unless your child is vegan or vegetarian, there’s no need for them to take a B12 supplement, the only exception is if it is recommended by a medical professional.

Should women take a vitamin B12 supplement during pregnancy?

If you eat meat, you’ll get all the B12 you need. However, if you’re vegetarian or vegan and pregnant, talk to your GP for advice.

The final say

Vitamin B12 is a vital nutrient that is essential for a variety of functions in your body. From producing red blood cells to DNA synthesis, the importance of vitamin B12 is clear, but it can be difficult for some to maintain their levels.

Luckily, with the help of a balanced diet, most people can get the recommended daily dose of vitamin B1.




1.       https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-b/

2.       https://vegsoc.org/info-hub/health-and-nutrition/vitamin-b12/

3.       https://www.hsph.harvard.edu/nutritionsource/vitamin-b12/

4.       https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/

5.       https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257642/

6.       https://ods.od.nih.gov/factsheets/VitaminB12-Consumer/

7.      https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/618167/government_dietary_recommendations.pdf

8.     https://www.statpearls.com/articlelibrary/viewarticle/24915 

9.     https://www.ncbi.nlm.nih.gov/pmc/articles/PMC490077/

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