When we think about supporting the immune system and the nutrients we need for this, we may be more inclined to think of vitamins and minerals such as Vitamin C, Zinc and vitamin D. The fact is of course, that every single vitamin and mineral, whether directly or indirectly, supports your immunity, but a vitamin you perhaps wouldn't immediately associate with an immune boost, is B12.
This amazing and safe vitamin does in fact play a number of crucial roles in keeping you in good health and research is still learning new ways in which this vitamin can support the body’s ability to fight off pathogens.
What is B12
B12 is one of eight of the water soluble B vitamins and has no known toxicity levels. It can be taken to urine tolerance – ie when you start to see pink urine then you have saturated body stores.
One of the ultimate multi-taskers its roles are varied, from DNA synthesis and supporting the metabolism to supporting a healthy nervous system and energy production.
Methylcobalamin and 5-deoxyadenosylcobalamin (Adenosylcobalamin) are the forms of vitamin B12 that the human body is able to use
B12 is actually produced in the human body, although it is done so by bacteria in the colon and is therefore less likely to be effectively absorbed this far down from the small intestine, where most nutrient absorption takes place.
Amongst B12’s important roles in the body, is its crucial role in supporting the immune system. The ways in which it does this are varied and we’ll take a closer look now at why B12 is essential in fighting off pathogenic bacterias and viruses.
Nitric oxide
As essential to life as oxygen, Nitric oxide (NO) is a molecule produced naturally by your body, and it's important for many aspects of your health. In the past two decades, NO has been recognised as one of the most versatile players in the immune system. It is involved in the pathogenesis and control of infectious diseases, tumours, autoimmune processes and chronic degenerative diseases. The significance of B12 is that adequate levels are crucial in the regulation of NO to ensure correct levels are produced by the cells. (1)
Natural Killer Cells
Natural Killer Cells (NK) are lymphocytes (white blood cells) forming part of the innate immune system and they respond quickly to a wide variety of pathological challenges. Additionally, NK cells secrete cytokines such as IFNγ and TNFα, which act on other immune cells like Macrophage and Dendritic cells to enhance the immune response. (2)
When a person becomes unwell, they usually present with low levels of natural killer cells which has allowed the pathogen to proliferate and take hold in the body. B12 is essential for the up regulation of NK cells and a deficiency will lead to low production and impaired activity. Worth noting is that these cells are some of the most important in destroying cancer cells. (3)
Red Blood Cells
In relatively new research (4), it has been found that red blood cells have an immune function. Previously thought of mostly as just oxygen carriers, studies have now shown that the cells serve as a sort of caretaker for normal cleanup duties, clearing up potentially harmful DNA that leaks into the circulation from the many body cells that die every day. But, during an infection or after an injury, this DNA may flood the bloodstream. The red blood cells then sacrifice themselves by encouraging macrophages to eat them, alert the immune system, and trigger inflammation. B12 is one of the most important vitamins for the optimal production of healthy and active red blood cells.
Tumour Necrosis Factor
You may have heard more about cytokines in recent years, specifically the term ‘cytokine storm’ in relation to Covid-19. TNF-a is a pro-inflammatory cytokine. Part of the innate immunity, they signal to other parts of the immune system as part of the inflammatory response. B12 plays an important role in regulating the production of this cytokine. (5)
An essential role in immunity
B12 is an essential regulator of inflammation and immune response in the body and it does seem to have a prophylactic action by supporting the immune system both directly and indirectly. Maintaining adequate levels of this vitamin form a crucial part of a healthy, well functioning immune system.
Foods rich in B12
To ensure you maintain good levels of B12, diet should always be your first port of call and the following foods are the best sources of this vitamin:
- Organ meat
- Meat
- Fish
- Milk
- Cheese
- Eggs
If you’re following a vegan diet, whilst fortified nutritional yeast is an option, it will often be fortified with cyanocobalamin, which is an inactive form of B12 which your body must not only convert to either Methylcobalamin or Adenosyslcobalamin, it must also first remove the cyanide compounds bound to the cobalt. Whilst only a tiny amount, it’s worth avoiding this toxic compound where possible.
Supplementation
In some cases, such as in people over 60, those with poor gut health or for those following a vegan or vegetarian diet, supplementation is required to maintain
Methylcobalamin and Adenosylcobalamin forms. This offers the body both active forms which can be used for all biochemical processes without the need for any conversion. Liquids are also an optimal choice as these can be taken sublingually (under the tongue) and absorbed straight into the bloodstream, avoiding the liver first-pass.
Read my article on THE TOP 6 SIGNS OF B12 DEFICIENCY, AND ANOTHER 5 THAT MAY SURPRISE YOU! to see if your B12 levels could do with a boost as we enter into cold and flu season. 
Rachel Aceso
Nutritionist and CEO
