Vitamin B12, Cobalamin has the highest B number of 12, as it has the largest molecular structure of any vitamin and contains the mineral Cobalt. This points to its incredible importance as a conversion co factor for gaining energy from carbohydrate, protein and fat. It is essential for our red blood cell production from bone marrow, for daily cellular replication and to retain nerve health through maintaining its protective sheath. Vitamin B12 is only found in foods of animal origin, predominantly; red meat, poultry, fish and shellfish such as clam and oyster, egg and milk products (although dairy is far less bioavailable than other meat sources listed). Whilst some B12 is found in some fermented products such as tempeh and sauerkraut, as well as nori and black trumpet mushrooms, the Vitamin B12 in these products occurs mainly as inactive analogs and is not utilised by humans.

There are many obstacles that prevent absorption of vitamin B12 including;

1. inadequate secretion of stomach acid and pepsin – both of these compounds free the B12 we take in from food and allow it to be absorbed. From around 35 years and older, our secretion of both stomach acid and pepsin reduces, and by the age of 50 and over, our bodies ability to produce adequate HCI (hydrochloric acid) declines significantly.
2. Inadequate secretion of intrinsic factor (IF) – IF is a protein secreted by special cells in the stomach and is required for adequate absorption of B12.
3. Inadequate secretion of pancreatic enzymes; which are required to free up B12 ready for absorption.
4. Bacteria and parasites compete for absorption of B12
5. Calcium is also required for B12 absorption, and high doses of Vit C (500mg+) within one hour of eating a meal may diminish all absorption
6. Some pharmaceutical drug interactions also destroy absorption.

Insufficiency and deficiency symptoms, either from insufficient intake or from malabsorption conditions such as Crohn’s disease include;

1. Elevated blood Homocysteine levels –  B12, together with B6 and B9 Folate is required to lower this potentially dangerous amino acid, homocysteine. Elevated levels of homocysteine reduce our bone density and may stimulate atherosclerotic plaque development, resulting in cardio vascular disease, heart attack and stroke. Your level can be accurately checked through your GP. To lower homocysteine it is recommended to supplement B12 up to 400ug/day in conjunction with up to 2.5mg/day of B9 Folate and up to 25mg/day of B6.
2. Gastrointestinal disturbances – very common in the elderly. Symptoms include reduced appetite, indigestion, diarrhoea/constipation, flatulence, red painful tongue or smooth shiny tongue.
3. Nerve damage – causing both physical and emotional challenges. Physically, tingling and numbness in arms, legs, fingers and difficulty with balance (in chronic deficiencies it may result in paralysis). Emotionally, mood changes, insomnia, confusion, depression and inability to concentrate are caused through spinal cord and brain nerve deficiencies. These changes occur slowly, and often once experienced the symptoms are irreversible!
4. Megaloblastic anaemia – resulting in fatigue, decreased stamina, palpations, and skin pallor due to an inability to form red blood cells that carry oxygen sufficiently.
5. Recurrent Miscarriage – there have been some studies to suggest a correlation.

It is therefore suggested for all vegans and some vegetarians to supplement, due to limited quantity and quality. Likewise, for those over the age of 55 to supplement due to the changes in digestive bioavailability.