Your body needs vitamin B12 to help keep the blood cells and nerve cells healthy and functioning correctly. Most people get enough vitamin B12 through the diet, but some medical conditions prevent proper absorption of the vitamin, requiring supplementation. Adults need 2.4mcg of vitamin B12 per day, according to the Office of Dietary Supplements. Taking supplemental forms of vitamin B12 may help treat medical conditions caused by a deficiency.
Vitamin B12 Deficiency
Eating a vegetarian or vegan diet may lead to a vitamin B12 deficiency because most food sources of the vitamin come from animal products such as dairy products and meat. Having a condition that blocks the body's ability to absorb vitamin B12 from food or supplements may also lead to a deficiency. Signs and symptoms of a vitamin B12 deficiency include fatigue, weakness, low blood pressure and vision problems. Administration of vitamin B12 as an intramuscular injection or as a nasal gel may help correct the deficiency.
Infertility
Males suffering from infertility related to low sperm counts and sperm mobility may benefit from taking vitamin B12 supplements. Taking the supplement as a intramuscular injection may help improve sperm motility and increase sperm counts, according to the University of Maryland Medical Center.
Breast Cancer
Although vitamin B12 will not cure breast cancer, normal levels of the vitamin may help prevent breast cancer. Studies suggest that women with more folate and vitamin B12 in the diet have lower incidence of developing breast cancer, while postmenopausal women with low amounts of vitamin B12 have an increased risk of breast cancer, according to the University of Maryland Medical Center.
Pernicious Anemia
Pernicious anemia is a condition that causes a decrease in red blood cells in the blood. Red blood cells help carry oxygen throughout the body. Vitamin B12 helps produce red blood cells. Having a condition that blocks the absorption of vitamin B12 may cause pernicious anemia. Symptoms of the condition include deceased appetite, fatigue, bleeding gums, shortness of breath and nerve damage that leads to dementia, depression as well as numbness and tingling. Using injectable forms of vitamin B12 monthly may help correct the deficiency.
Heart Disease and Stroke
A high level of an amino acid called homocysteine increases the risk of developing heart disease or a stroke. Vitamin B12 may help keep the levels of homocysteine levels low in the body.
