Te mimititanga huaora B12 me te mate waihanga pūtau toto whero Vitamin B12 deficiency and pernicious anaemia

Most people get vitamin B12 from animal foods such as eggs, dairy, meat and seafood. It is not found in fruit and vegetables. You also need a protein called 'intrinsic factor' in your stomach to be able to get the vitamin B12 into your blood.

Pernicious anaemia

The most common cause of vitamin B12 deficiency is a condition called pernicious anaemia. It is an autoimmune condition that causes antibodies from your own immune system to attack the cells in your stomach that make a protein called intrinsic factor. This means your body cannot absorb vitamin B12. We do not know why this happens.

Pernicious anaemia usually develops in people aged over 50. Women are more often affected than men. It tends to run in families. It occurs more often in people who have other autoimmune diseases.

Other causes

People at risk of vitamin B12 deficiency include:

• vegans
• breastfed infants of vegan mothers — these babies can develop anaemia within months of being born because they have not had enough time to store vitamin B12 in their bodies
• older people and others who have a poor appetite and eat very small meals
• people with digestive conditions such as Crohn's disease and coeliac disease
• people who have had surgery to remove their stomach, or the last part of their small bowel
• people on medicines that affect the absorption of vitamin B12.

If you have low red blood cells such as in pernicious anaemia, you might:

• feel tired and faint, be breathless, look pale and feel your heart thumping (palpitations)
• have a sore tongue or mouth ulcers
• get pins and needles or numbness
• have vision problems
• feel unsteady
• experience depression, confusion or memory problems.

See your healthcare provider if you have any of these symptoms.

Severe or long-lasting pernicious anaemia

Severe or long-lasting pernicious anaemia can damage your heart, brain and other organs. It can also cause other problems, such as:

• nerve damage
• memory loss
• gut problems.

You may also have a higher risk for weakened bone strength and stomach cancer.

A blood test can measure your red blood cell count and Vit B12 levels.

A blood test can be done to check antibodies to intrinsic factor found in pernicious anaemia

You can help yourself by choosing good food sources of vitamin B12, such as:

• meat, chicken, seafood and eggs
• cow's milk and milk products such as yoghurt, cheese and ice cream
• foods strengthened with vitamin B12, such as some soy, almond, oat and rice milks and some yeast extracts, such as Marmite.

If you have mild vitamin B12 deficiency, you may be able to increase your levels by taking vitamin B12 or vitamin B complex supplements. You can buy them from some pharmacies and supermarkets. You will need at least 50 mcg (micrograms) of Vitamin B12 a day.

If you have more serious vitamin B12 deficiency, you will need vitamin B12 injections to replace and maintain your body stores of vitamin B12. If you have pernicious anaemia, you will need these injections every 2 to 3 months for the rest of your life.