Vitamin B-12 is necessary for a healthy nervous system and healthy blood cells. The best way to get vitamin B-12 is through your diet.

Vitamin B-12 is an important vitamin found in meat, fish, poultry, and dairy products. If you don’t eat enough of these foods, it may leave you with a deficiency.

Read on to learn the causes of B-12 deficiency, what it may mean for your overall health, and what you can do about it.

B-12 is mostly found in animal products. It doesn’t occur naturally in plants.

As a result, people who don’t eat meat or dairy products, such as vegetarians and vegans, may be at risk of B-12 deficiency. Some vegetarian foods, including breakfast cereals and energy bars, may be fortified with B-12.

Consuming enough vitamin B-12 isn’t the only problem. Your body also needs to be able to absorb it efficiently.

Certain medications may make it harder for your body to absorb B-12, including:

Very low levels of vitamin B-12 can result in serious complications, including anemia.

Another possible symptom of a B-12 deficiency is losing your sense of taste and smell. More serious symptoms include fast or irregular heartbeat and shortness of breath.

B-12 deficiency may also lead to peripheral neuropathy with symptoms that may include numbness, weakness, pain, and paresthesia (a burning or itchy sensation of the skin). It’s usually felt on the arms, hands, legs, and feet. Some people experience numbness, tingling, or a prickly feeling.

Low B-12 tends to be associated with high levels of an amino acid called homocysteine. This can increase your risk of heart disease and stroke.

A severe, long-term B-12 deficiency may cause:

One of the potential complications of diabetes mellitus is neuropathy, also called nerve damage. It’s caused by the adverse effects of high blood glucose over a long period.

The most common symptoms of diabetic neuropathy are those described above for peripheral neuropathy that often affect arms, hands, legs, and feet.

Diabetic neuropathy can also affect other body parts, including the gastrointestinal (GI) tract.

You don’t have to have diabetes to develop neuropathy. Prolonged B-12 deficiency may also damage your nerves.

Whether you have diabetes or not, symptoms of neuropathy should not be ignored.

If you have symptoms of B-12 deficiency, see your doctor right away. Some of the symptoms, especially early on, can be vague. They can also be caused by a variety of other things.

A simple blood test can determine if the problem is low B-12. If you have diabetes and/or B-12 deficiency, your doctor will want to perform a complete history and physical examination to fully evaluate you.

Your blood glucose levels will also be taken into account in regard to diabetes mellitus.

Recommended levels of B-12 vary by age. Most teens and adults need 2.4 micrograms (mcg) per day. Children need between 0.4 and 1.8 mcg each day, depending on their age.

You may be advised to increase B-12 in your diet. Good sources of vitamin B-12 include:

Foods that may be fortified with B-12 include:

Be sure to read nutrition labels carefully.

Your doctor may also advise you to take oral vitamin B-12 supplements, especially if you have a vegetarian or vegan diet. If you’re severely deficient, your doctor may give you B-12 injections. B-12 injections are also recommended if the reason for the B-12 deficiency is a decreased ability to absorb B-12 through your gut— injections bypass the barriers to absorption.

Follow your doctor’s advice to avoid serious complications of B-12 deficiency.

Diabetic neuropathy may be caused by prolonged high blood glucose levels. This and a B-12 deficiency may damage your nerves, with or without diabetes.

If you’re concerned about your B-12 levels, you may want to see your doctor to discuss doing bloodwork and other testing as needed.