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Vitamin B12 Disadvantages

author image Susan Ferrandino
Susan Ferrandino began writing in 2005. She started writing health and nutrition articles online during the summer of 2010. Some of her articles focus on Omega 3 fatty acids and nutrition with pregnancy. She has been working in the health-care industry for over 10 years and is pursuing her Master of Science in women's health.
Vitamin B12 Disadvantages
Pile of vitamins. Photo Credit: vnarong/iStock/Getty Images

Vitamin B-12, also called cobalamin, makes up part of the eight B vitamins essential to the human body. This vitamin supports the nervous system and brain, energy production and formation of blood. The human body cannot produce vitamin B-12 so it must be acquired in a balanced diet or supplements. Side effects can occur when not enough vitamin B-12 is consumed. Vitamin B-12 can interfere with certain medications. Before taking this vitamin, consult your health care provider to ensure its safety.

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Drug Interactions

While most physicians consider vitamin B-12 safe, it can interact with medications, according to the University of Maryland Medical Center. Medications such as glucophage for diabetes, chemotherapy, anticonvulsants and stomach- acid reducers decrease the overall absorption of vitamin B-12. This results in vitamin deficiencies even if you take the recommended daily allowance of 2.4 mcg for adults. If you take these medications, discuss vitamin B-12 intake with your health care provider or a nutritionist.

Decreased Absorption in Elderly

Vitamin B-12 needs a healthy digestive system and stomach acid in order to be absorbed properly. In the elderly, the ability to absorb vitamin B-12 is lessened with the aging process. This is a disadvantage because deficiencies will occur. The symptoms are fatigue and anemia. If an elderly person is cognitively impaired, these symptoms may go unnoticed. It is important for elderly people to have their vitamin B-12 levels checked with their health care provider.

Pernicious Anemia

Vitamin B-12 needs a component in the stomach called intrinsic factor. It is made by the stomach cells and enables absorption of this vitamin. Pernicious anemia results with a lack of vitamin B-12. In normal amounts, this vitamin generates healthy red blood cells that carry oxygen and nutrients to the body. Without this, you may experience weakness, numbness in your fingers, diarrhea and weight loss. Severe pernicious anemia symptoms include memory loss, confusion and loss of balance. Your health care provider can identify a problem with intrinsic factor and the disadvantage of poor vitamin B-12 absorption. This condition can be treated with injection vitamin B-12.

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