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Are You At Risk For Vitamin B-12 Deficiency?

Source: Diabetes Forecast, April 2007

Vitamin B-12 is found in animal-derived foods such as meat, milk, and eggs. This essential vitamin keeps nerves and red blood cells healthy. Deficiency can lead to anemia, nerve damage, tiredness, weakness, depression, weight loss, and numbness and tingling in the hands and feet.

People with diabetes run a heightened risk of vitamin B-12 deficiency.

Some Causes

Three steps are required for the body to get enough vitamin B-12:

1. Hydrochloric acid in the stomach releases vitamin B-12 from food.

2. Vitamin B-12 combines with a substance called “intrinsic factor.”

3. The intestines then absorb B-12.

Disruption at any step can lead to deficiency.

Autoimmune Diseases

In celiac disease, foods containing the protein gluten inflame the intestines so they cannot properly absorb some nutrients, including vitamin B-12. Celiac disease occurs in about one in 20 people with type 1 diabetes. Gluten is found in most breads, noodles, and many other grain foods.

In pernicious anemia, the immune system interferes with production of intrinsic factor, impairing absorption of vitamin B-12. Pernicious anemia occurs in perhaps 1 to 2 percent of people with type 1 diabetes.

Older Age

Type 2 diabetes most often occurs in people over 50 years old. Perhaps a third of people that age produce too little stomach acid to release B-12 from food.


The type 2 diabetes pill metformin (Glucophage, Fortamet, Riomet) indirectly interferes with vitamin B-12 absorption in some people. About 30 percent of long-term metformin users do not absorb vitamin B-12 properly.

A study of metformin users in the October 9, 2006 issue of the Archives of Internal Medicine found that the risk of vitamin B-12 deficiency in metformin users increased with higher doses and longer use of the drug. Being a vegetarian also appeared to raise the risk of vitamin B-12 deficiency in this study, as has been found in vegetarians in general, particularly those who do not consume dairy products or eggs.

Weight-Loss Surgery

After surgery on the stomach or intestines, vitamin B-12 may not be absorbed properly.

What To Do

If you have celiac disease, are older than 50, or take metformin, ask your doctor if you should be taking vitamin B-12 supplements. If you have had weight-loss surgery, you should already be on a vitamin supplement; deficiencies of several vitamins may occur after such surgery.

Early treatment can reverse problems caused by deficiency.

Vitamin B-12 deficiency caused by metformin use can be lessened by calcium carbonate supplements.

Vitamin B-12 pills work just as well as shots in most people. The usual supplement dose is 1 mg daily. Sometimes, shots are given first to quickly build up levels of vitamin B-12, which vitamin B-12 pills can then maintain.

However, severe deficiencies cannot be treated by pills alone; if you have symptoms of B-12 deficiency, seek medical attention and have a B-12 test performed.