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Vitamin B12 food, sources and deficiency

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What is vitamin B12

Vitamin B12 is a nutrient that is needed by the body to help keep nerve and blood cells in good condition. It is water soluble and used by every cell in the body. Vitamin B12 also helps to make the genetic material in cells (DNA) and prevents a form of anaemia that causes people to feel fatigued (tired) and weak.

Why do we need B12?

Your body needs vitamin B12 to make red blood cells and keep your nervous system healthy and working properly. The nutrient B12 also helps to release the energy you need from food and it also helps your body to use folic acid. If you don’t get enough B12 from the foods you eat or supplements you could develop a vitamin B12 deficiency and anaemia.

What foods have vitamin B12?

Foods high in B12 include meat such as lamb and beef, fish including salmon and cod, milk, cheese and eggs. There are also plenty of breakfast cereals that are fortified with the vitamin that can help you get the amount you need. B12 is not found naturally in vegetables, fruits or grains, which means if you are a vegetarian or vegan, you may find it hard to get enough B12. However B12 can be found in nutritional yeast, which has a savoury cheese-like flavour and can be added to vegan meals such as vegetarian pesto pasta and cauliflower dairy-free cheese.

Other vitamin B12 sources

B12 can also be found in nutritional yeast, which has a savoury cheese-like flavour and can be added to vegan meals such as vegetarian pesto pasta and cauliflower dairy-free cheese.

Vitamin B12 can also be found in supplements and can even be administered through injection for those who are severely deficient.

Vitamin B12 supplements

You should be able to get all the vitamin B12 your body needs by eating a healthy, balanced and varied diet, however if you need to boost your B12 levels you can take supplements. B12 supplements can help to combat feelings of tiredness and fatigue, as well as supporting a healthy pregnancy.

What does it mean when you have low vitamin B12?

If your levels of B12 are low, it means that your body doesn’t have enough healthy red blood cells. These blood cells carry oxygen around the body and then returns carbon dioxide to the lungs so that you can exhale it.

Vitamin B12 deficiency symptoms

Being deficient in B12 can lead to anaemia, which is a term to describe the blood cells in your body. Your red blood count can be low which means that your body is not getting enough oxygen.

B12 deficiency symptoms include:

  • Feeling extremely tired
  • Lacking energy
  • Experiencing pins and needles
  • A red tongue that is sore
  • Muscle weakness
  • Ulcers inside your mouth

Neurological symptoms of B12 deficiency can include:

  • Feelings of confusion
  • Depression
  • Trouble remembering things and memory problems
  • Issues with understanding and judgement

If you are experiencing any of symptoms and think you might be deficient in B12 visit your GP. They will be able to assess your symptoms and diagnose you based on a blood test.

How much B12 should I take?

Adults aged between 19 and 64 need 1.5mcg of vitamin B12 a day*. If you eat meat and dairy products you should be able to get enough B12. For example 85g of salmon contains 4.8mcg of B12, 236ml of semi-skimmed milk contains 1.2mcg of b12 and one boiled egg contains 0.6mcg**.

How can I add more B12 to my diet?

Fish is an excellent source of B12, especially mackerel, salmon and clams. It is recommended that you should include two portions of fish a week into your diet, to help boost your levels of essential vitamins and minerals.

What happens if I have too much B12?

Vitamin B12 is a nutrient which is water soluble; meaning that if you take too much the excess tends to be removed from the body in your urine. However the effects of taking too much B12 have yet to be evidenced.

How soon does vitamin B12 start working?

The length of time it takes for you to feel improvements from vitamin B12 depends on how deficient you were to begin with. Usually, supplements are taken over a period of months during which time you may gradually begin to feel improvements in your energy levels.

How long should I take B12 supplements?

The length of time you should be taking B12 supplements depends on the nature of your deficiency. If you’re low on B12 because of your diet, you’ll likely need to take supplements alongside your meals until your doctor or healthcare practitioner says your levels have improved. It won’t be harmful to you to be on vitamin B12 supplements unnecessarily as they are water-soluble, meaning any excess amount in your body is excreted through urine.

Does B12 help you lose weight?

There is no significant evidence that administering vitamin B12 injections will help you to lose weight. Some are advertised as boosting energy and therefore metabolism, but unless you are deficient in B12 you will be unlikely to experience an increase in energy.

References

*www.nhs.uk/conditions/vitamins-and-minerals/vitamin-b/#vitamin-b12
**www.ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional
www.nhs.uk/news/neurology/vitamin-b12-and-brain-volume
www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia
www.ods.od.nih.gov/factsheets/vitaminb12-consumer
www.nhs.uk/conditions/red-blood-count
www.nhs.uk/live-well/eat-well/fish-and-shellfish-nutrition/#how-much-fish-should-we-eat

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