Proudly New Zealand Owned

Vitamin B12 - essential for good health

By Nadia McMorran

Vitamin B12, also known as cobalamin, is an essential micronutrient. It enables our cells to grow and replicate, helps us to metabolise carbohydrates, fats and proteins and is involved in the production of red blood cells in our bone marrow. It is the largest of the B vitamins and contains a central cobalt atom, which is then bound to enzymes to enable it to be absorbed in the gut.

Cobalamin is available in a number of different forms, with the most common three being

Cyanocobalamin, a synthetic form of B12 that binds cyanide to the cobalt atom.

Hydroxycobalamin, where a hydroxyl group is attached to the cobalt, and is the injectable form that you may receive from your doctor when very deficient.

Methylcobalamin, the most absorbable and efficient form that has a methyl group bound to the cobalt atom.

Some common symptoms of severe vitamin B12 deficiency include anaemia, impaired memory and irritability, depression, dementia, loss of appetite, constipation and diarrhoea, abdominal pain, dizziness, paleness, loss of vision or hearing, or a feeling of pins and needles.

Some possible causes of vitamin B12 deficiency include:

Following a vegetarian or vegan diet

Conditions affecting your absorption of vitamins and minerals such as Crohn’s disease, coeliac disease, parasites, diverticulitis, ulcerative colitis and inflammatory bowel disease

Anaemia, particularly pernicious anaemia

Candida overgrowth in the gut

Autoimmune diseases

Diabetes (both type I and type II)

Long term use of antacids

Use of the oral contraceptive pill

Antibiotic use

Heavy drinking

Deficiencies in folate, iron or vitamin E

Vitamin B12 is synthesised in the gut from the foods that you eat. Unfortunately, vegetarian and vegan diets are frequently deficient in vitamin B12, as vegetables and grains are not sufficient in providing adequate vitamin B12.

To find out what your vitamin B12 levels are, you will need a blood test that either your doctor can request, or you can request it yourself at your local medical testing centre.

An adult requires a minimum of 2.4mcg of vitamin B12 daily, either through food or supplementation. This minimum recommendation only provides the amount necessary for the body to function without illness, so it is important to get more than this to achieve optimum health.

Foods that contain vitamin B12:

Egg yolk

Dairy products

Meat and organ meats such as liver and kidneys


Salmon and sardines