Prevent a Vitamin B12 Deficiency

A vitamin B12 deficiency can lead to anemia and nerve damage. Learn why and find out the warning signs.

You need vitamin B12 to produce blood cells and for your nervous system (which controls pretty much everything) to function properly. In order for the body to use vitamin B12, the vitamin must bind to a protein substance called intrinsic factor, which is produced in the lining of the stomach.

A true dietary deficiency is rare, as most of us get plenty of vitamin B12 in our diets. Very high levels of vitamin B12 are found in foods like liver, clams, and other mollusks, but beef, fish, and fortified breakfast cereals are also good sources of the complex vitamin.

“The body only needs a small amount," explains Paul Thomas, EdD, RD, a dietitian and scientific consultant with the National Institutes of Health’s Office of Dietary Supplements. Yet most Americans consume four to five micrograms a day [of vitamin B12] — "and we only need two to three," says Elizabeth Pash Penniman, MS, RD, LD, a dietitian with the Cleveland Clinic in Ohio. "Our body can store several years’ worth of B12."

Vitamin B12: Who’s At Risk for Deficiency?

As we age, the lining of the stomach produces less intrinsic factor, which can greatly reduce the body’s absorption of vitamin B12. Also, those who follow a strict vegan diet with no animal products may be at risk for developing a vitamin deficiency.

Others at risk include people with certain medical conditions that do not permit sufficient vitamin B12 absorption, such as:

• Pernicious anemia
• Crohn’s disease
• Fish tapeworm infection
• Weight loss surgery 

Vitamin B12: Recognizing Signs of Vitamin Deficiency

The primary symptom of a vitamin B12 deficiency is a sore, red tongue. However, there are a number of other symptoms, including:

• Fatigue
• Loss of appetite
• Decreased sense of vibration
• Numbness or tingling in the hands and feet
• Sore mouth and tongue
• Weakness
• Anemia
• Poor memory, confusion, and depression in advanced cases

“If you have the signs or symptoms, I would recommend getting a blood test," says Penniman. A blood test can usually determine the specific cause of your symptoms, many of which may be seen in other conditions, including folate deficiency.

Vitamin B12: Preventing Vitamin Deficiency

Prevention is important for people of all ages, as a deficiency can lead to anemia and, in some cases, irreversible damage to the nervous system. The most common treatment is B12 supplements given either orally or by injection, and it is generally effective.

Because we produce less intrinsic factor as we age, taking an oral supplement is recommended for people over the age of 60.

Vegans and vegetarians should also consider taking B12 supplement, either orally or by injection. “B12 comes from animal sources, so if you’re a complete vegan you should be taking a B12 vitamin supplement because you could become anemic," Penniman says, “and so could your child if you’re a nursing mother."

If you’re concerned that you might be at risk of a vitamin B12 deficiency, talk to your doctor about how to include more B12-rich foods in your diet and whether a supplement is right for you.