| Vitamin :: Vitamin B12 |
| Other Terms: | Cobalamin | Cyanocobalamin | Cobamide |
| Solubility: | Water soluble, which means any excess can be excreted in urine. Water-soluble vitamins are usually not kept in the body in any significant amounts, but vitamin B12 differs in that the body can store it in the liver and other tissues for a long time. Deficiency is therefore less likely. |
| On this Page: | What is Vitamin B12 · Benefits · Deficiency Signs · Foods · Supplements · RDA · Toxicity | Overdose |
What is Vitamin B12 ?
Vitamin B12 is one of the B-Complex vitamins. It is also called cobalamin, cyanocobalamin, or cobamide, as it contains the heavy metal cobalt.
It is unusual in that it needs to combine with another substance, a protein made in the stomach called intrinsic factor (IF), to find its way from the intestinal tract into the bloodstream where it is used.
Vitamin B12 is fairly stable and not much depleted by cooking.
How Vitamin B12 Benefits Health
Like the other B vitamins, vitamin B12 has a key role in maintaining healthy nerves and skin. It is also important for energy production, red blood cell formation, creation of DNA (the genetic material in all cells), and metabolic processes of the body.
It is essential to get enough of this vitamin because of its importance to almost every body system. This list summarizes how vitamin B12 benefits our health.
| :: | Vitamin B12 Benefits & Functions |
| 1. | needed for the metabolism of proteins, fats and carbohydrates, and for synthesis of amino acids, fatty acids, and energy production |
| 2. | essential for red blood cell formation and to prevent pernicious anemia |
| 3. | needed to make DNA, the genetic material in all cells that is necessary for cell replication and development |
| 4. | enables nerve cells to develop properly and prevents nerve damage |
| 5. | preliminary research indicates potential (together with vitamin B6 and folic acid) for reducing risk of heart attack and cardiovascular disease, by lowering levels of homocysteine that is associated with atherosclerosis (hardening and narrowing of arteries) |
| 6. | recent studies seem to indicate that vitamin B12 is important for brain health, as older people with lower levels appear to be more prone to brain atrophy (shrinking), which is associated with Alzheimer’s disease and cognitive decline |
| 7. | evidence that vitamin B12 with fish oil may be more effective than fish oil alone in reducing triglycerides and blood cholesterol levels |
Vitamin B12 Deficiency Symptoms and Causes
The elderly are the most at risk. Vitamin B12 deficiency can also be due to a deficient diet, or due to malabsorption, where the body has difficulty absorbing the vitamin from food.
People with gastrointestinal disorders, such as celiac disease and Crohn’s disease, that interfere with absorption of food or production of Intrinsic Factor, or who don’t produce enough stomach acids needed to release B12 from food, are therefore at risk of deficiency. They, as well as the elderly, might benefit from vitamin B12 supplements.
Long-term medication for heartburn or ulcers, excessive alcohol, laxatives, anti-coagulant drugs, anti-gout medication, sleeping pills, antibiotics, and nicotine, may deplete this vitamin and raise intake required.
As plant foods contain little of this vitamin, strict vegetarians might need vitamin B12 supplements. This is especially so for those who are pregnant women or breastfeeding mothers. Vitamin B12 deficiency in infants, if left untreated, can cause irreversible nerve damage.
Sometimes vitamin B12 deficiency is misdiagnosed as folic acid deficiency as the body needs vitamin B12 to make use of folic acid. If, as a result, extra folate is taken instead of B12, then the B12 deficiency will worsen.
Vitamin B12 deficiency symptoms and diseases can also occur when the body cannot use it properly.
One of the classic vitamin B12 deficiency symptoms is pernicious anemia, a serious form of anemia characterized by large immature red blood cells. By the time it is detected however, deficiency might have been present for a while. (Pernicious anemia in turn aggravates the deficiency by destroying cells in the stomach that help absorb vitamin B12.)
| :: | Vitamin B12 Deficiency Symptoms |
| 1. | megaloblastic or pernicious anemia (anaemia) characterized by fatigue, weakness, diarrhea, weight loss, pale skin, sore red tongue or mouth |
| 2. | hypotension (low blood pressure) |
| 3. | loss of appetite |
| 4. | nerve damage symptomized by tingling and numbness in the hands and feet, loss of balance, unsteady movement, muscle weakness, spasticity, or incontinence; such nerve damage may be irreversible if left untreated |
| 5. | heart palpitations |
| 6. | even mild deficiency can cause confusion, disorientation or hallucination |
| 7. | mood disturbances like depression, irritability or nervousness |
| 8. | memory loss or dementia |
| 9. | some Alzheimer’s disease patients have been found to have unusually low vitamin B12 levels |
| 10. | dandruff |
| 11. | vision problems |
| 12. | higher levels of homocysteine that may cause blood clots or build-up of plaque in arteries and lead to heart disease or cardiovascular problems |
| 13. | researchers reported that women with breast cancer appear to have lower B12 levels, which causes less folate to be available for DNA repair and replication; risk may possibly be reduced by taking more vitamins B6 and B12 and methionine in the diet |
| 14. | deficiency symptoms in infants include retarded growth or development, movement disorders, and anemia |
Vitamin B12 Foods
Food rich in vitamin B12
· animal liver · fish like cod, halibut, herring, mackerel, salmon, snapper, trout.
Other foods with vitamin B12
· dairy products · egg yolk · kidney · meat (beef, lamb, pork, poultry, venison) · seafood like clams, scallops and shrimp.
Vitamin B12 Supplements
Taking vitamins and minerals in their correct balance is vital to the proper functioning of all vitamins. They work synergistically, which means that the effectiveness of any one nutrient requires or is enhanced, sometimes dramatically, by the presence of certain other nutrients.
For this reason, if you are looking to take supplements for maintenance of optimal health, the recommended approach is to take a multi-vitamin that has the proper balance of all the necessary nutrients your body needs.
For a list of reputable top ranked vitamin and mineral supplements chosen in an independent supplement review, see Best Multivitamin Supplements. Many of these are manufactured to pharmaceutical or nutraceutical GMP compliance, which is the highest multivitamin standard possible.
Keep in mind, however, that while vitamin supplements are useful to plug nutritional gaps that are almost inevitable in modern diets, and to ensure we get optimal doses ofnutrients, they are no substitute for a good diet. Instead, use them to complement a healthy diet and lifestyle.
Vitamin B12 RDA (Recommended Dietary Allowance)
The Food & Nutrition Board of the Institute of Medicine, National Academy of Sciences, in their 1997-2001 collaboration between the US and Canada, set the daily Adequate Intake (AI) of Vitamin B12 as follows.
| Life Stage | Gender | Vitamin B12 Dosage | Day |
| Infants 0-6 mths | 0.4* µg |
| Infants 7-12 mths | 0.5* µg |
| Children 1-3 yrs | 0.9 µg |
| Children 4-8 yrs | 1.2 µg |
| Girls 9-13 Yrs | 1.8 µg |
| Boys 9-13 Yrs | 1.8 µg |
| Females 14-18 Yrs | 2.4 µg |
| Males 14-18 Yrs | 2.4 µg |
| Females 19-50 Yrs | 2.4 µg |
| Males 19-50 Yrs | 2.4 µg |
| Females older than 50 Yrs | 2.4 µg |
| Males older than 50 Yrs | 2.4 µg |
| Pregnant Women 14-18 Yrs | 2.6 µg |
| Pregnant Women 19-50 Yrs | 2.6 µg |
| Lactating Mothers 14-18 Yrs | 2.8 µg |
| Lactating Mothers 19-50 Yrs | 2.8 µg |
These dosages are the minimum required per day to ward off deficiency. In therapeutic use of this nutrient, dosage is increased as necessary for the ailment, keeping in mind Vitamin B12 toxicity levels.
Legend
1 µg = 1 mcg = 1 microgram = 1/1,000,000 of a gram
1 mg = 1 milligram = 1/1,000 of a gram
* Indicates AI figures based on Dietary Reference Intake (DRI) figures
Vitamin B12 Overdose Symptoms, Toxicity Level & Side Effects
No vitamin B12 side effects have been reported from overdose, even from scientific studies of high doses daily over a period of several years.
When the Food and Nutrition Board of the Institute of Medicine, National Academy of Sciences established its 1998 DRI guidelines, it did notset a Tolerable Upper Intake Level (UL) due to lack of data on adverse vitamin B12 side effects.
In the absence of guidelines, however, it is still wise to avoid vitamin B12 overdose (excessive amounts above the RDA) except for therapeutic use under a healthcare professional.
Moreover, people allergic to cobalt should avoid vitamin B12 supplements.
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References
| 1. | Institute of Medicine, Food and Nutrition Board. Dietary reference intakes for thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline. Washington, DC: National Academy Press; 1998. |
| 2. | U.S. National Libary of Medicine [NLM] & National Institutes of Health [NIH]: MedlinePlus. NLM-NIH home page. <http://www.nlm.nih.gov/medlineplus>. Use the built-in search function to find specific data. Accessed 2009 March – June. |
| 3. | National Institutes of Health, NIH Clinical Center: Office of Dietary Supplements [ODS]. ODS home page. <http://ods.od.nih.gov>. Use the built-in search function to find specific data. Accessed 2009 Mar – Jun. |
| 4. | The George Mateljan Foundation: The world’s healthiest foods [WHFoods]. WHFoods home page. <http://www.whfoods.com>. Accessed 2009 March – June. |
| 5. | Mayo Foundation for Medical Education and Research. Mayo Clinic book of alternative medicine: The new approach to using the best of natural therapies and conventional medicine. New York, NY: Time Inc; 2007. p 67-75. |
| 6. | Balch JF, Balch PA. Prescription for nutritional healing: A practical A-Z reference to drug-free remedies using vitamins, minerals, herbs & food supplements. Garden City Park, New York: Avery Publishing; 1990. |
| 7. | Ulene A. Dr. Art Ulene’s complete guide to vitamins, minerals and herbs. New York, NY: Avery Publishing; 2000. |
