If you follow a plant based diet, it is likely that you are already aware of the importance of B12. The question of why we need B12 is one we often receive so we have put together a brief snapshot including deficiency signs/symptoms as well as factors that increase demand for this vital nutrient.
What is B12?
Vitamin B12 (Cyanocobalamin) is complex and essential nutrient for a healthy nervous system, blood cell formation, blood sugar metabolism as well as many other critical biochemical processes. There are also a number of enzymes that require B12. Therefore the impact of deficiency of this nutrient is wide ranging and can have serious consequences on our health. In some cases, the deficiency symptoms are irreversible.
All nutrients require certain other nutrients (known as co-factors) for maximum absorption and in order to convert the nutrient into its active form. Some nutrients can mask deficiency of others, for example folate is normally consumed in adequate amounts in vegan diets and can mask a B12 deficiency in terms of anaemia serology, however will not prevent nerve damage that may be caused by the lack of B12. Equally B12 is important to activate folate.
Vitamin B12 absorption requires a substance called intrinsic factor, (released in the stomach) and requires the presence of other nutrients, for example, calcium.
It is important to note that whilst there have been claims that algae products such as spirulina are a source of Vitamin B12, this is controversial as the B12 may not be in a form that is bioavailable. Some even suggest that the B12 analogue in spirulina may interfere with B12 metabolism and actually reduce B12 status. This means that the presence of Vitamin B12 in a food does not necessarily mean that this nutrient is absorbed.
It is good to be aware, however, that some plant based ingredients are fortified with B12. For example, nutritional yeast. This is a great inclusion to vegan/vegetarian diets however not all brands are fortified so be sure to read the label.
As a snapshot, to illustrate the complexity of this nutrient, here are some factors to consider.
Adequate functional Vitamin B12 levels requires all of the following:
- Sufficient Vitamin B12 in the diet
- Sufficient stomach acid for absorption
- Sufficient gastric enzymes
- Release of intrinsic factor by parietal cells in the stomach (this does not occur in those with auto-immune disease, pernicious anaemia
- Recognition of Vitamin B12 by intrinsic factor
- Sufficient co-factors, particularly calcium
Some factors that increase demand for Vitamin B12 are:
- Gastric bypass surgery
- Vegetarian and vegan diets
- Imbalance of gut flora
- Auto-immune disorders
- Certain medications, including oral contraceptive pill
- Parasitic infections (tapeworm)
- Excessive alcohol consumption
Signs and symptoms of Vitamin B12 deficiency include:
- Hearing loss
- Mood disorders
- Numbness or tingling of hands and feet
Of course these symptoms may have a number of causes and need to be investigated by a medical practitioner.
Due to the number of individual variables, we recommend that all vegans and vegetarians be tested for their Vitamin B12 status (including active B12) to assess whether supplementation is required. As Vitamin B12 is stored in the liver, it can take a long time (years) before deficiency signs manifest. For some, Vitamin B12 injections are required due to inability to absorb this nutrient orally.