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How Does Vitamin B12 Help Your Immune System?

Vitamin B12 (less commonly known as cobalamin) is a water-soluble vitamin that plays a vital role in the functioning of the human nervous system. It is one of eight different B vitamins and, compared to all other vitamins, is the largest and most complex structurally.

In order to stay healthy and support your immune system, it’s important to maintain the right levels of Vitamin B12 in your body. In this guide, we will explain more about vitamin B12 and immune system functioning.

In this guide:

Learn more about the role vitamin B12 plays

Discover how vitamin B12 can affect your immune system

How to make sure you’re getting enough vitamin B12

How much vitamin B12 should you be taking?

Learn more about how to identify whether or not you’re experiencing a vitamin B12 deficiency

What are the key benefits of vitamin B12 for your body?

Vitamin B12 plays a fundamental role in the body’s production of red blood cells. Without adequate levels of the vitamin in your body, the production of red blood cells can be impacted and can affect the transportation of oxygen to vital organs, causing weakness and fatigue.

In addition, inadequate levels of vitamin B12 can reduce bone mineral density, causing bones to become fragile over time.

Vitamin B12 works alongside a range of B vitamins to help support your body’s functions. Vitamin B complex helps to support a healthy immune system by supporting cell health, red blood cells, energy levels and cardiovascular health, among other functions. This means it’s important to make sure you not only get enough vitamin B12, but B vitamins as a whole.

How vitamin B12 supports the immune system

Vitamin B12 and folic acid are both vital for immune function. Both are necessary for producing a sufficient number of red blood cells to carry oxygen around the body. If you have a folate deficiency and/or vitamin B12 deficiency, your immune system may start to falter, and your body will struggle to ward off pathogens. Red blood cells are crucial immune cells which are part of your body’s immune response so it’s important to ensure they’re able to form and function correctly.

A lack of vitamin B12 in your diet or through supplements can lead to pernicious anaemia. Pernicious anaemia is an autoimmune disorder that causes the immune system to attack stomach cells, thus inhibiting the body’s ability to absorb vitamin B12. Although the cause of this condition is unknown, supplements can help with the symptoms of pernicious anaemia.

As you can see, vitamin B12 is a key vitamin for helping to maintain a healthy immune system and maintaining levels of both vitamin B12 and folic acid will help to prevent conditions such as pernicious anaemia and folate deficiency.

Key sources of Vitamin B12

Vitamin B12 can be obtained from a number of sources so if you feel like you’re suffering from a deficiency or would like to ensure you’re getting enough to support your immune system, here are some of the key sources:


Supplements are one of the easiest and most convenient methods to get enough vitamin B12 into your body without having to worry about making significant changes to your diet.

How to take vitamin B12 supplements

Vitamin B12 supplements usually come in the form of oral sprays or tablets. Tablets are often the most popular choice, but oral sprays are very easy to take and provide an effective solution for those who find tablets difficult to swallow.

Best Vitamin B12 oral sprays

BetterYou Boost B12 Oral Spray

BetterYou’s vitamin B12 oral spray offers immune support though oral spray technology.

Main features

  • Delivers 1,200μg of vitamin B12
  • Apricot flavouring
  • Stimulant free
  • Vegan approved

Click here to view product page

better you oral spray
BetterYou B-complete Oral Spray

BetterYou’s B-complete oral spray provides an expertly formulated blend of all 8 B vitamins, including Vitamin B12.

Main features

  • Supports natural energy production
  • Delivers nutrients directly to bloodstream
  • Natural peach, plum and raspberry flavour
  • Vegan approved
  • Complete B vitamin supplement

Click here to view product page

better you b complete spray


Most meat contains high levels of vitamin B12 but some of the most vitamin B12-rich meats include:

  • Beef
  • Venison
  • Turkey


Shellfish is very high in vitamin B12 and, generally speaking, if you eat plenty of oysters and mussels, you are unlikely to require supplements unless you are already suffering from anaemia.

Fortified cereals

Fortified cereals have added vitamin B12 and folic acid so, to check whether your favourite cereal contains vitamin B12, remember to check the packaging.


Most oily fish contains high levels of vitamin B12. The following types of fish are good choices:

  • Salmon
  • Tuna
  • Trout
  • Sardines

Milk and dairy

Most milk and dairy products such as cheese, yoghurt and cream contain relatively high levels of vitamin B12.

Recommended vitamin B12 dosages

The following table lays out the recommended daily allowance (RDA) of vitamin B12 for a range of age groups. These represent a minimum daily recommendation and it should be noted that there is no recommended safe upper limit. This is because it is safe to take high levels of vitamin B12 as the body only absorbs as much as it needs, expelling the rest as waste.

Age Amount (μg)
0-6 months 0.4 μg
7-12 months 0.5 μg
1-3 years 0.9 μg
4-8 years 1.2 μg
9-13 years 1.8 μg
14+ years 2.4 μg

It should also be noted that pregnant women should try to consume at least 2.6μg of vitamin B12.

Key symptoms of vitamin B12 deficiency

There are a variety of symptoms to look out for that may indicate a vitamin B12 deficiency. These include:

  • Fatigue
  • Irritability
  • Mouth ulcers
  • Constipation
  • A yellow tinge to the skin
  • Sore tongue
  • Pins and needles
  • Behavioural changes
  • Memory problems

If you follow a vegetarian or vegan diet, it is particularly important to take note of these symptoms. This is because most foods that contain high levels of vitamin B12 and other essential vitamins are animal products. Fortunately, you can still maintain a vegetarian or vegan diet and address a vitamin B12 deficiency with the help of supplements. At BetterYou, we provide a Vegan Health Oral Spray to help you make sure you’re getting enough vitamin B12 and to prevent a vitamin B12 deficiency.

If you think you may be suffering from a vitamin B12 deficiency but want to make sure, you can now take a vitamin B12 test at home.

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