Vitamin B12, also known as cobalamin for its cobalt content, is one vitamin that is often lacking in strict vegetarian diets as it is found almost exclusively in animal products. It works in conjunction with the other B vitamins, especially folate / folic acid, and needs calcium for proper functioning. As you age, your need for vitamin B12 increases.
Natural Food Sources
Beef, blue cheese, cottage cheese, clams, dairy products, egg, fish, liverwurst, oysters, Swiss cheese.
Vitamin B12 helps in red blood cell formation and making neural sheaths. It increases energy, promotes growth, keeps your mind sharp as you age, helps the immune system work and can prevent heart disease. Vitamin B12 shots are often given to treat pernicious anemia and may be effective in treating Alzheimer's disease.
Vitamin B12 is stored in the liver so it may take years for a serious deficiency to manifest. Pernicious anemia, sore mouth and tongue, weakness, mental disorders, insomnia, tingling sensations, body odor, menstrual disturbances and neuritis are among deficiency symptoms. Severe vitamin B12 deficiency may result in spinal chord degeneration and paralysis.
There is a very low incidence of vitamin B12 toxicity even in doses of 1000 mcg per day - any excess is excreted in urine. If taken with large doses of vitamin C, it may cause nosebleed, ear bleeding or dry mouth.
Dietary Reference Intake