Food & Recipes

Vitamin B12 Deficiency

Vitamin B12 has many important functions in the body. It works with the B vitamin folate to make our body's genetic material. It helps keep levels of the amino acid homocysteine in check, which may help decrease heart disease risk, and it is essential to the production of red blood cells, which carry oxygen through the blood to the body's tissues.

But many people are deficient in this important vitamin.

Causes of Vitamin B12 Deficiency

Vitamin B12 deficiency can have a number of possible causes. Typically it occurs in people whose digestive systems do not adequately absorb the vitamin from the foods they eat. This can be caused by:

• Pernicious anemia, a condition in which there is a lack of a protein called intrinsic factor. The protein, which is made in the stomach, is necessary for vitamin B12 absorption.
• Atrophic gastritis, a thinning of the stomach lining that affects up to 30% of people aged 50 and older.
• Surgery in which part of the stomach and/or small intestine is removed.
• Conditions affecting the small intestine, such as Crohn's disease, celiac disease, bacterial growth, or a parasite.
• Excessive alcohol consumption.
• Autoimmune disorders, such as Graves' disease or systemic lupus erythematosus
• Long-term use of acid-reducing drugs.

Vitamin B12 deficiency can also occur in vegetarians, because the best food sources of the vitamin are animal products. Strict vegans (people who don't eat any animal products, including meat, eggs, or milk) are at greatest risk. Vegetarians who eat eggs and milk products are also at risk, because, on average, they consume less than half the adult Recommended Dietary Allowance (RDA) of vitamin B12.  

Babies born to mothers who are vegetarians may also be deficient in vitamin B12.

Symptoms of Vitamin B12 Deficiency

A deficiency of vitamin B12 can lead to vitamin B12 deficiency anemia. A mild deficiency may cause only mild, if any, symptoms. But as the anemia worsens it may causes symptoms such as:

• weakness, tiredness or light-headedness  
• rapid heartbeat and breathing
• pale skin
• sore tongue
• easy bruising or bleeding, including bleeding gums
• stomach upset and weight loss
• diarrhea or constipation

If the deficiency is not corrected, it can damage the nerve cells. If this happens, vitamin B12 deficiency effects may include:

• tingling or numbness in fingers and toes
• difficulty walking
• mood changes or depression
• memory loss, disorientation, and dementia

B12 deficiency in infants, if not detected and treated, can lead to severe and permanent damage to the nervous system. New mothers who follow a vegetarian diet should have their babies' B12 levels checked by a doctor.