Many older adults are unaware of a common and easily treatable condition - vitamin B-12 deficiency. Recent studies indicate that up to 10 percent to 15 percent of adults older than 65 have a vitamin B-12 deficiency called pernicious anemia.

Pernicious anemia is a form of anemia in which the body is not able to absorb enough vitamin B-12 from the digestive tract. Although it can be difficult to diagnose a vitamin B-12 deficiency because its symptoms are often subtle, treatment is easy and effective.

What is vitamin B-12?

Vitamin B-12, also called cyanocobalamine or cobalmin, is an essential nutrient. It is essential for the development of red blood cells and it plays an important role in the normal function of the nervous system.

Vitamin B-12 is found primarily in food of animal origin, such as meat, milk products and eggs and also in yeast extracts, such as brewer's yeast. Most people are able to obtain the two micrograms (mcgs) needed daily from their diet, so it is unusual for this to be the cause of a deficiency--except among vegans (individuals who are total vegetarians and consume absolutely no foods of animal origin).

Vitamin B-12: The US Recommended Dietary Allowances
Age	US RDA
Infants: under 6 months	0.3 mcg
6-12 months	0.5 mcg
Children: 1-3 years	0.7 mcg
4-6 years	1.0 mcg
7-10 years	1.4 mcg
Men and Women: 11 years and older	2.0 mcg
Pregnant Women:	2.2 mcg
Nursing Women:	2.6 mcg
Source: Recommended Dietary Allowances: National Academy of Sciences, 10the ed., 1989.

What is pernicious anemia?

Although you may get enough vitamin B-12 from your diet, you can still have a vitamin B-12 deficiency if you have a problem that makes it difficult for the vitamin to be absorbed into your bloodstream. Intrinsic factor, a protein made by cells in the stomach that links to vitamin B-12, helps get vitamin B-12 absorbed into the body. It is then transported to the liver where it is stored until it is needed.

Absence of intrinsic factor is the most common cause of pernicious anemia. The reason for the absence is unknown, but it is more common in people with autoimmune disorders such as Graves' disease, type I diabetes and thyroiditis. (The tendency to form autoimmune disorders may be inherited.) It is thought that the body makes antibodies against the cells in the stomach lining that produce the intrinsic factor.

Pernicious anemia is also seen in people who have had part, or all, of their stomach removed for cancer or other reasons, as well as in people with atrophic gastritis or those who take antacids.

Many older people develop atrophic gastritis, a chronically inflamed and scarred stomach that leads to a decrease in the acid level in the stomach, or take antacids (medicines that lower stomach acids) with their meals. Vitamin B-12 needs intrinsic factor along with this stomach acid to be absorbed from the diet.

What are the symptoms of pernicious anemia?

In general, symptoms develop quite slowly, taking one to five years to deplete all the vitamin B-12 that is stored in the liver. Vitamin B-12 deficiency can lead to damage of nerve cells with symptoms including tingling and numbness in the hands and feet, difficulty walking, muscle weakness, irritability, memory loss, dementia and depression. Some older people are actually diagnosed with dementia and in reality have a vitamin B-12 deficiency.

How is it diagnosed and treated?

The sooner a vitamin B-12 deficiency is recognized and treated, the more effective the treatment. This is of particular importance because taking vitamin B-12 supplements may stop the progression of nerve damage, but not reverse the nerve damage itself.

There are several blood tests available to diagnose vitamin B-12 deficiency. One test measures the amount of vitamin B-12 in your blood, another test determines whether you have antibodies to your intrinsic factor, while a third test can measure the body's ability to absorb vitamin B-12. Based on the results of these tests your doctor can determine the type of treatment you will need.

Neither oral vitamin B-12 supplements nor dietary changes are useful because of the poor absorption in the stomach. Therefore, initially, patients are usually treated with daily vitamin B-12 injections.

With proper treatment, symptoms of pernicious anemia usually begin to improve within a few days. After several days, treatment may only be required once a month. However, it must continue for a lifetime. Until recently the doctor prescribed a monthly injection (shot), but now there is a new nasal gel available, called Noscobal, which allows treatment without injections and a visit to the doctor.


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