Symptoms of Low B12 may earn compensation through affiliate links in this story.
Image Credit: Christopher Robbins/Digital Vision/Getty Images

Vitamin B-12, also called cobalamin, helps make DNA and keeps nerve and blood cells healthy. A deficiency in Vitamin B-12 can cause irreversible damage to the nerve cells and impair the quality of life. One in five adults over age 51 has a vitamin B-12 deficiency. Adults get 2.6 micrograms of Vitamin B-12 daily, according to the National Institutes of Health. You can find vitamin B-12 in fortified breads and breakfast cereals, meat, fish, poultry, and dairy products.


One symptom of a vitamin B-12 deficiency is megaloblastic anemia. Megaloblastic anemia occurs when the red blood cells are not able to develop properly and they become very large. The body produces fewer red blood cells, and this can cause symptoms including abnormal paleness, decreased appetite, fatigue and weakness.

Neurological Symptoms

Because cobalamin is involved with the development of nerve cells, low levels of vitamin B-12 can result in nerve damage. The most common neurological symptom of a deficiency is a tingling sensation in your hands and feet, also known as paresthesias. Patients may also experience weakness, a change in motor skills, changes in vision or even behavioral changes in the form of dementia, depression, or hallucinations.

Gastrointestinal Symptoms

Often, people who experience low vitamin B-12 have symptoms that involve the intestinal tract. Symptoms may include flatulence, constipation, diarrhea or anorexia. These symptoms could lead to unwanted weight loss. Patients might experience gastrointestinal symptoms, without having anemia or neurological symptoms.

Growth and Development

Due to its role in creating DNA and the function of nerve and blood cells, a vitamin B-12 deficiency could be harmful for a pregnant woman and growing children. Pregnant women who are low in cobalamin are at greater risk of neural tube birth defects. Infants and young children who are deficient in vitamin B-12 may be diagnosed with failure to thrive, experience developmental delays, develop anemia, have low muscle tone or experience general weakness.

Show Comments