According to WebMD, the main benefits of vitamin B12 include helping the body maintain a healthy nervous system and creating new blood cells. Newsmax notes that other benefits of vitamin B12 include maintaining a healthy digestive system and keeping hair and nails strong and healthy.
WebMD reports that vitamin B12 can also be used for memory loss, boosting mood and energy levels and improving concentration. Additionally, vitamin B12 is likely effective in reducing a condition related to heart disease called hyperhomocysteinemia. Vitamin B12 may also be effective in preventing an age-related disease of the eye called macular degeneration. Topical vitamin B12 can be applied to the skin to treat psoriasis and eczema.
According to WebMD, a deficiency of vitamin B12 can result in a form of anemia called megaloblastic anemia and cause such side effects as fatigue, weakness, upset stomach and pale skin. A blood test determines the level of vitamin B12 found in the blood. Vitamin B12 is found in foods such as meat, shellfish, milk and cheese. Therefore, levels of the vitamin can be increased with a properly managed diet or vitamin B12 supplements. The amount of vitamin B12 that is recommended varies and depends on a person's age.