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Vitamin B12 is best known and most promoted as a cure for fatigue, but this very important vitamin is important for much more than keeping energy levels up. Vitamin B12 deficiency symptoms include everything from depression, fatigue, and memory loss to canker sores and dizziness.
Many people with vitamin B12 deficiency don’t have fatigue
Vitamin B12 plays crucial roles in maintaining the health of your blood cells, digestive system, brain, and nervous system. And while fatigue (due to anemia) is sometimes a symptom, recent research shows that many people have vitamin B12 deficiency without anemia or significant fatigue. Instead, they have vitamin B12 deficiency symptoms that are more related to impairments in the nervous system.
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Low vitamin B12 symptoms most often caused by impaired nervous system
In the nervous system, the B12 vitamin is necessary for the formation of myelin, a whitish insulating sheath around nerve fibers that increases the speed at which impulses are conducted. It is also needed for the production of some neurotransmitters. Vitamin B12 deficiency, therefore, results in defective myelin synthesis and neurotransmitter imbalances, leading to a host of mental, emotional, and physical symptoms related to the nervous system.
The most common symptoms of low B12
- Abnormal sensation, typically numbness, tingling or pricking (“pins and needles”) of the lower legs and feet (both sides)
- Weakness in the legs
- Increased risk of falling
- Memory loss
- Attention deficits
- Psychosis (suspiciousness, persecutory or religious delusions, auditory and visual hallucinations and disorganized thought processes)
- Sore, swollen, beefy red tongue
- Sores at the corners of the mouth
- Recurrent canker sores
- Burning sensation of the mouth
- Shortness of breath on exertion
- Decreased bone health and increased risk of fracture
- Mild diarrhea or constipation
- Impaired vision
- Possible increased risk of cardiovascular disease
- Possible increased risk of cancer
- Lightheadedness or fainting, possibly accompanied by a rapid increase in heartbeat, after standing up from a lying down position
Causes of low B12 symptoms
Causes of vitamin B12 deficiency include not eating animal products, not making enough stomach acid (hypochlorhydria, common with aging), an autoimmune disorder called pernicious anemia, and certain medications, especially acid-blocking medications (proton pump inhibitors and H2 blockers) for GERD and acid reflux, and metformin for diabetes.
Treating vitamin B12 deficiency symptoms
Treatment for vitamin B12 deficiency usually starts with B12 injections. Some patients need regular injections for life, depending on the cause of the deficiency. After vitamin B12 shots have returned the body’s levels to normal, it’s possible to switch to oral vitamin B12 supplements.
A Vitamin B12 supplement may contain a few different forms of the vitamin, including cyanocobalamin, methylcobalamin, hydroxocobalamin, and adenosylcobalamin. While all these forms are capable of treating vitamin B2 deficiency, methylcobalamin is superior for oral use. The typical recommended dose for treating vitamin B12 deficiency is 2,000 micrograms per day.
For information on food sources of vitamin B12, see “The Top B12 Foods for Every Diet,” where you’ll find information on the best dietary sources of vitamin B12 for meat-eaters, vegetarians, and vegans.
Share Your Experience
Do you have a vit B12 deficiency? Or have you treated it in the past? What strategies work best for you?
This post originally appeared in 2014 and has been updated.