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What's vitamin B12 and why's it so important?

jodi-johnson

Written byJodi M Johnson

heeral-patel-bio

Reviewed byHeeral Patel

Young woman eat breakfast with knife and fork, Morning in cafe. Healthy breakfast with wholemeal bread toast with avocado, poached egg with green
From turning food into energy to red blood cell formation, vitamin B12 is key to keeping you healthy. Energise your knowledge and find out how you can support your intake

Summary

1What is vitamin B12?

Vitamin B12 is a water-soluble nutrient that has several different roles in keeping your body healthy. All B vitamins, like folic acid and...

2Vitamin B12 sources

As your body doesn’t make or store vitamin B12, it’s important to get enough through your diet. Animal products like beef, pork, eggs...

3What happens if you don’t get enough vitamin B12?

Low B12 symptoms can include tiredness, headaches, palpitations, loss of appetite, a sore red tongue…

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You might be thinking, what is B12 good for? Well, it’s one of the eight B vitamins that play a vital role in keeping our bodies in tip-top condition.1

From reducing fatigue to looking after our nervous system and red blood cells. It supports our energy, bone health, contributes towards normal brain function.2

So, with that in mind, let's find out why this vitamin’s so important to B12 at its best.

What is vitamin B12?

Vitamin B12 is a water-soluble nutrient that has several different roles in keeping your body healthy. All B vitamins, like folic acid and niacin, are important for helping your body convert food into energy, but B12 plays a key role in various other bodily functions too.3

It's a vitamin that’s naturally present in a lot of food sources as it’s bound to protein in many different types of food. B12 is also water soluble, meaning it dissolves when in contact with water in your body. So, we need to make sure we get enough of it every day through our diets as our bodies can’t store or make it.

You’ll find vitamin B12 as a supplement in various forms and it can be labelled with different names. Cyanocobalamin4 is the man-made form of vitamin B12 that’s used to treat vitamin deficiencies5 and is sometimes listed on B12 supplements.

Why is vitamin B12 important?

This vitamin helps to support the following:1
  • normal energy-yielding metabolism
  • normal functioning of the nervous system
  • normal homocysteine metabolism
  • normal psychological function
  • normal red blood cell formation
  • the normal function of the immune system
  • the reduction of tiredness and fatigue
  • vitamin B12 has a role in the process of cell division

How does B12 support energy?

Woman stretching in the park with gym clothes on. Happy expression
One of B12’s main roles is to help with the production and development of red blood cells that carry oxygen around our bodies.6

Oxygen travels from your lungs into the blood and flows to all your vital organs: the brain, lungs and muscles.7 If these organs don’t receive enough, they’ll slow down, and you can find yourself feeling fatigued.

What are sources of vitamin B12?

Your body doesn’t make or store vitamin B12, so it’s important to get enough through your diet. Animal products like beef, pork, eggs, milk, cheese and fish are all great sources.8

Vitamin B12 can sometimes be found in fortified breakfast cereals and nutritional yeast, but for vegans and vegetarians, this might not be enough. It’s worth speaking to a dietician or nutritionist about alternative ways you can get enough vitamin B12 if you’re vegan or vegetarian, to make sure you don’t develop a deficiency.

What happens if you don’t get enough vitamin B12?

The NHS recommends adults consume at least 1.5mcg1 of vitamin B12 a day, which can be easy if you eat enough vitamin B12 rich foods. If you can’t reach these levels, you could be at risk of developing a deficiency.

Low B12 symptoms2 can include:
  • tiredness
  • headaches
  • palpitations
  • loss of appetite
  • sore red tongue
You can test your vitamin B12 levels with an at-home testing kit. While these tests shouldn’t replace seeing your doctor for any concerns, they can help you better understand your health and get proactive about your wellbeing.

It’s essential to note that these home tests can’t give you a 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.

The final say

Vitamin B12 is a key nutrient that has many important roles within your body.

But maintaining adequate levels of vitamin B12 can be a struggle as it’s mainly found in animal products like meat, cheese and eggs. So, for those who follow a vegan or vegetarian diet taking a supplement may be necessary.

Disclaimer

This article provides informational advice and is not a substitute for medical care. Curated by experts for accuracy, we take great care to ensure the information is up-to-date and relevant. However, you should always consult your GP or healthcare professional before using supplements or alternative products, particularly if you have medical conditions or are under supervision.
 

Sources

  1. NHS. B Vitamins and Folic Acid - Vitamins and Minerals [Internet]. NHS. 2020. Available from: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-b/‌
  2. NHS. Vitamin B12 or Folate Deficiency Anaemia Symptoms and Treatments [Internet]. www.nhsinform.scot. 2023. Available from: https://www.nhsinform.scot/illnesses-and-conditions/nutritional/vitamin-b12-or-folate-deficiency-anaemia/‌
  3. NHS. Vitamin B12 or Folate Deficiency Anaemia Symptoms and Treatments [Internet]. www.nhsinform.scot. 2023. Available from: https://www.nhsinform.scot/illnesses-and-conditions/nutritional/vitamin-b12-or-folate-deficiency-anaemia/‌
  4. NHS website. About cyanocobalamin [Internet]. nhs.uk. 2024. Available from: https://www.nhs.uk/medicines/cyanocobalamin/about-cyanocobalamin/‌
  5. Vasavada A, Sanghavi D. Cyanocobalamin [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2020. Available from: https://www.ncbi.nlm.nih.gov/books/NBK555964/‌
  6. Kumar R, Singh U, Tiwari A, Tiwari P, Sahu JK, Sharma S. Vitamin B12: Strategies for enhanced production, fortified functional food products and health benefits. Process Biochemistry [Internet]. 2023 Apr 1;127:44–55. Available from: https://www.sciencedirect.com/science/article/abs/pii/S1359511323000363?casa_token=mODFguD7CdwAAAAA:o53TFbbb9CoMnRVDMUYxEM_sMvH-F1MDjGIgoFe-5OsAfGr7ybn-bRPnRSNPsN-RL_aq1QzGpg‌
  7. Institute for Quality and Efficiency in Health Care. How do lungs work? [Internet]. Nih.gov. Institute for Quality and Efficiency in Health Care (IQWiG); 2016. Available from: https://www.ncbi.nlm.nih.gov/books/NBK401240/‌
  8. Watanabe F. Vitamin B12 sources and bioavailability. Experimental biology and medicine (Maywood, NJ) [Internet]. 2007;232(10):1266–74. Available from: https://www.ncbi.nlm.nih.gov/pubmed/17959839‌
 

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