Why Vitamin B12 is important

Vitamin B12 plays a critical role in something called the Methylation Cycle. This cycle plays a role in building and breaking down key ingredients for a healthy functioning body. It also helps to activate or deactivate a variety of important things that effect most of the systems of the body. The Methylation Cycle’s range of functions contribute to our physical and mental processes working properly. It directly impacts on:

• Our energy production

• DNA/RNA repair and maintenance

• Repair and maintenance of cell membranes

• Activation and deactivation of neurotransmitters (e.g. it helps us convert serotonin to melatonin)

• Detoxification and immune system support

• Cartilage production

Why is Vitamin B12 important?

Vitamin B12 is known as a co-factor which means that it helps convert Product A into Product B. In the context of the Methylation Cycle it helps (along with Vitamin B9 or Folate) to recycle something called Homocysteine back into Methionine - see diagram below.

If we have insufficient levels of vitamin B12 then we get a build up of homocysteine in our system. Homocysteine is pro-inflammatory and highly toxic. It has been linked to a range of health issues, including:

• Heart disease

• Stroke/clots

• Dementia and cognitive decline

• Cancer

• Multiple Sclerosis

• Pre-eclampsia

Getting adequate vitamin B12 along with other B vitamins (B2, B6, Folate), either through diet and/or supplementation helps to keep our levels of homocysteine at healthier low levels.

What are the symptoms of low vitamin B12?

There are 3 common symptoms of vitamin B12 deficiency or insufficiency:

• Persistent pain, pins and needles or numbness (especially if it’s in multiple areas of the body)

• Fatigue

• Depression or irritability

Other symptoms people may experience are: mouth ulcers, a sore or red tongue (glossitis), and disturbed vision.

Can I test my vitamin B12 levels?

Testing our vitamin B12 levels is not at straightforward as it might seem. Blood tests tell us the amount of active and inactive forms of vitamin B12 found in the blood. It is estimated that 70-90% of vitamin B12 in the blood is bound to a carrier which means that it is inactive. 10-30% is active. As these ranges vary considerably it means that determining average “optimal” levels of vitamin B12 can be tricky because there is a potentially wide range of normal values. A test showing deficient levels of vitamin B12 is clear, however if we test in the lower range of “normal” we may in fact still have insufficient levels.

It is for this reason that the BJH (British Journal of Haematology) guidelines recommends that we supplement with vitamin B12 when a clinical picture is suggestive of deficiency even in the presence of a “normal” vitamin B12 test.

Why is vitamin B12 deficiency common?

There are two reasons for vitamin B12 deficiency:

• Lack of vitamin B12 in our diet

• Poor absorption

Foods which are high in vitamin B12 include animal products (meat, eggs, fish, cheese, and especially offal including liver and kidneys), mushrooms, and seaweed. 

The main reason vitamin B12 deficiency is not uncommon is because it is not as readily absorbed in our digestive tract as some other B vitamins. In order for us to absorb it we require good levels of hydrochloric acid (HCl) and intrinsic factor, both produced in the stomach. This means people who have conditions such as Crohn’s disease, IBS, coeliac disease, gut dysbiosis, SIBO, and also general digestive impairment including bloating, diarrhoea and constipation. There are also certain medications linked to deficiency including Metformin (used for diabetes) and Omeprazole (a Proton Pump Inhibitor used for acid reflux). 

When is it important to use a supplement?

Supplementation is particularly advisable in cases of neurological symptoms (pins and needles, or numbness) because long-term deficiency can lead to irreparable damage. If you suspect that you are vitamin B12 deficient then seek advice from a healthcare practitioner before considering supplementation. They are best placed to ascertain if a deficiency is likely and/or provide you with an avenue for further testing. They can also advise you on an appropriate dose and if there are any health reasons why supplements should be avoided (contraindications).

When supplementing with vitamin B12 it is best to use a sublingual form (which dissolves under the tongue) because so many people have trouble absorbing it through the gut. It is also important to ensure that you chose an active form of B12 which are either the methylcobalamin or adensylcobalamin forms. It is best to avoid the cyanocobalamin form which is inactive.