Vitamin B12, also called cobalamin, is important to good health. It helps maintain healthy nerve cells and red blood cells, and also is needed to make DNA, the genetic material in all cells. Vitamin B12 is bound to the protein in food. Hydrochloric acid in the stomach releases B12 from protein during digestion. Once released, B12 combines with a substance called intrinsic factor (IF) before it is absorbed into the bloodstream.
All of these B vitamins help the body in converting carbohydrates into glucose or sugar, which is burned in order to produce energy for proper body function. These are often referred to as B complex vitamins, and are essential for the breakdown of fats and proteins. They help maintain muscle tone, protect the mucus lining in the digestive tract and mouth, and promote upkeep of nervous system and the organs like the liver, skin, hair, and eyes. Cobalamine is an excellent anti-stress vitamin since it is believed to enhance the health functioning of the immune system and improve the body’s ability to fight stressful conditions.
B12 injections have been found to frequently improve energy levels and general well-being. They also support thyroid function to regulate energy levels. B12 also reduces water retention owing to its diuretic attributes. Vitamin B12 is naturally found in animal foods, including fish, milk and milk products, eggs, meat and poultry. Fortified breakfast cereals are an excellent source of vitamin B12 and a particularly valuable source for vegetarians. The table of selected food sources of vitamin B12 suggests dietary sources of vitamin B12.
The Recommended Dietary Allowance (RDA) is the average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97 percent to 98 percent) healthy individuals in each life-stage and gender group. The 1998 RDAs for vitamin B12 (in micrograms) for adults are 2.4 µg and the results of two national surveys, the National Health and Nutrition Examination Survey (NHANES III-1988-91) and the Continuing Survey of Food Intakes by Individuals (CSFII 1994-96) found that most adult men and women consume recommended amounts of vitamin B12.
Diets of most adult Americans provide recommended intakes of vitamin B12, but deficiency may still occur as a result of an inability to absorb B12 from food. It also can occur in individuals with dietary patterns that exclude animal or fortified foods. As a general rule, most individuals who develop a vitamin B12 deficiency have an underlying stomach or intestinal disorder that limits the absorption of vitamin B12. Sometimes the only symptom of these intestinal disorders is anemia resulting from B12 deficiency.
Characteristic signs of B12 deficiency include fatigue, weakness, nausea, constipation, flatulence (gas), loss of appetite and weight loss. Deficiency also can lead to neurological changes such as numbness and tingling in the hands and feet. Additional symptoms of B12 deficiency are difficulty in maintaining balance, depression, confusion, poor memory, and soreness of the mouth or tongue. Some of these symptoms also can result from a variety of medical conditions other than vitamin B12 deficiency. It is important to have a physician evaluate these symptoms so that appropriate medical care can be given.
Surgical procedures of the gastrointestinal tract such as surgery to remove all or part of the stomach often result in a loss of cells that secrete stomach acid and intrinsic factor. Surgical removal of the distal ileum, a section of the intestines, also can result in the inability to absorb B12. Anyone who has had either of these surgeries usually requires lifelong supplemental B12 to prevent a deficiency.
The Relationship Between Vitamin B12 and Heart Disease?
A deficiency of vitamin B12, folate or vitamin B6 may increase your blood level of homocysteine, an amino acid normally found in your blood. There is evidence that an elevated blood level of homocysteine is an independent risk factor for heart disease and stroke. The evidence suggests that high levels of homocysteine may damage coronary arteries or make it easier for blood-clotting cells called platelets to clump together and form a clot. However, there is currently no evidence available to suggest that lowering homocysteine level with vitamins will actually reduce your risk of heart disease. Clinical intervention trials are needed to determine whether supplementation with vitamin B12, folic acid or vitamin B6 can help protect against developing coronary heart disease.
Vitamin B12 has a very low potential for toxicity. The Institute of Medicine states “no adverse effects have been associated with excess vitamin B12 intake from food and supplements in healthy individuals.” The Institute recommends that adults older than 50 years of age get most of their vitamin B12 from supplements or fortified food because of the high incidence of impaired absorption of B12 from unfortified foods in this population.