What does fact checked mean?
At Healthfully, we strive to deliver objective content that is accurate and up-to-date. Our team periodically reviews articles in order to ensure content quality. The sources cited below consist of evidence from peer-reviewed journals, prominent medical organizations, academic associations, and government data.
The information contained on this site is for informational purposes only, and should not be used as a substitute for the advice of a professional health care provider. Please check with the appropriate physician regarding health questions and concerns. Although we strive to deliver accurate and up-to-date information, no guarantee to that effect is made.
Vitamin B12, a member of the vitamin B complex, is an essential vitamin 3. Your body cannot produce essential vitamins but requires them for normal biological functioning. Typically, your body quickly releases excess B vitamins in your urine, but your liver can store vitamin B12 for years 3. Chronic deficiency of vitamin B12 can deplete your stores and lead to a variety of adverse effects, including nerve damage 3.
Functions of Vitamin B12
Your body needs vitamin B12 for the production of red blood cells, DNA synthesis and maintenance of neurological function, the Office of Dietary Supplements reports 23. Vitamin B12, also known as cobalamin, plays an important role in the synthesis of methionine, which your body uses in nearly 100 different physiologic processes, including the synthesis of DNA, RNA, hormones, lipids and proteins 3. A critical part of the production of these compounds, vitamin B12 ensures that the body has enough energy and cellular components to survive 3. Your body overcomes temporary deficiencies in vitamin B12 by tapping into of the liver's reserves 3.
Vitamin B12 and Nerve Damage
Is B12 Water or Fat Soluble?
Your nervous system requires vitamin B12 for proper function and maintenance 3. According to the University of Maryland Medical Center, even mild deficiency can lead to signs of neurological dysfunction, such as nervousness, numbness and an abnormal tingling sensation in your extremities 1. Severe and chronic vitamin B12 deficiency can cause permanent nerve damage and complete loss of neurological function and sensation 3. Without vitamin B12 your nervous system is unable to conduct nerve impulses or sustain viable function 3. This inability quickly leads to nerve cell damage and deterioration. Elderly patients are often at risk for vitamin B12 deficiency owing to poor diet and a dysfunction in the digestive system 3. Vegans, patients suffering from malabsorptive conditions, HIV patients and people with an eating disorder are also at risk of vitamin B12 deficiency 3.
Vitamin B12 Requirements
To ensure that your body is receiving enough vitamin B12, the Office of Dietary Supplements has specified recommended daily allowances for the vitamin 23. These allowances vary depending on your age, gender and whether you are pregnant or breast-feeding. Newborns require 0.6 mcg per day, and this value slowly increases until adulthood. Adults of both genders require 2.4 mcg of vitamin B12 per day 3. Pregnant women require 2.6 mcg, whereas lactating mothers should consume 2.8 mcg of vitamin B12 per da 3y
Sources of Vitamin B12
Signs & Symptoms of Parathyroid Disease High Calcium
Vitamin B12 is present in many foods, particularly meat and poultry 3. Eating dairy products or drinking milk can also provide you with vitamin B12 3. Eggs and shellfish are excellent sources of the vitamin as well. In some cases, your doctor may recommend that you take vitamin B12 supplements, which are synthetically made vitamins that provide your body with adequate vitamin B12 23.
Vitamin B12 Overdose
Taking too much vitamin B12 can lead to an overdose and several adverse side effects 3. If you develop a skin rash or wheezing, consult your doctor immediately, the Mayo Clinic warns. These signs may be indications of a serious condition. Other side effects of vitamin B12 include diarrhea and mild skin irritation and itchiness 3.
Is B12 Water or Fat Soluble?
Signs & Symptoms of Parathyroid Disease High Calcium
How Much Vitamin A Is Required a Day?
Ativan & B Complex Vitamins
How Does Anesthesia Affect the Body?
What Are the Causes of Vaginal Itching & Foul Odor?
Tryptophan in Bananas & Insomnia
Causes of Headaches With Nausea & Dizziness
What Are the Functions of Carbohydrates & Protein?
Ambien and Hallucinations
- University of Maryland Medical Center: Vitamin B12 (Cobalamin)
- Office of Dietary Supplements: Vitamin B12
- Medline Plus: Vitamin B12
- Holick MF, Gordon CM. Patient Guide to Vitamin D Deficiency. The Journal of Clinical Endocrinology & Metabolism. 2011;96(7):1-2. doi:10.1210/jcem.96.7.zeg33a
- Sunyecz JA. The use of calcium and vitamin D in the management of osteoporosis. Ther Clin Risk Manag. 2008;4(4):827-836. doi:10.2147/tcrm.s3552
- Giovannucci E, Liu Y, Hollis BW, Rimm EB. 25-hydroxyvitamin D and risk of myocardial infarction in men: a prospective study. Arch Intern Med. 2008;168(11):1174-1180. doi:10.1001/archinte.168.11.1174
- Gorham ED, Garland CF, Garland FC, et al. Optimal vitamin D status for colorectal cancer prevention: a quantitative meta analysis. Am J Prev Med. 2007;32(3):210-216. doi:10.1016/j.amepre.2006.11.004
- Lappe JM, Travers-Gustafson D, Davies KM, Recker RR, Heaney RP. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. The American Journal of Clinical Nutrition. 2007;85(6):1586-1591. doi:10.1093/ajcn/85.6.1586
- Prentice RL, Pettinger MB, Jackson RD, et al. Health risks and benefits from calcium and vitamin D supplementation: Women’s Health Initiative clinical trial and cohort study. Osteoporos Int. 2013;24(2):567-580. doi:10.1007/s00198-012-2224-2
- Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr. 2010;91(5):1255-1260. doi:10.3945/ajcn.2009.29094
- Salehpour A, Hosseinpanah F, Shidfar F, et al. A 12-week double-blind randomized clinical trial of vitamin D₃ supplementation on body fat mass in healthy overweight and obese women. Nutr J. 2012;11:78. doi:10.1186/1475-2891-11-78
- Carrillo AE, Flynn MG, Pinkston C, et al. Impact of vitamin D supplementation during a resistance training intervention on body composition, muscle function, and glucose tolerance in overweight and obese adults. Clin Nutr. 2013;32(3):375-381. doi:10.1016/j.clnu.2012.08.014
- Marcinowska-Suchowierska E, Kupisz-Urbańska M, Łukaszkiewicz J, Płudowski P, Jones G. Vitamin D Toxicity-A Clinical Perspective. Front Endocrinol. 2018;9:550. doi:10.3389/fendo.2018.00550
- Ross AC, Manson JE, Abrams SA, et al. The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: what clinicians need to know. J Clin Endocrinol Metab. 2011;96(1):53-58. doi:10.1210/jc.2010-2704
- Bouillon R, Van Schoor NM, Gielen E, et al. Optimal vitamin D status: a critical analysis on the basis of evidence-based medicine. J Clin Endocrinol Metab. 2013;98(8):E1283-E1304. doi:10.1210/jc.2013-1195
- American Academy of Dermatology. Position Statement of Vitamin D. 2010.
- Taksler GB, Cutler DM, Giovannucci E, Keating NL. Vitamin D deficiency in minority populations. Public Health Nutr. 2015;18(3):379-391. doi:10.1017/S1368980014000457
- Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(7):1911-1930. doi:10.1210/jc.2011-0385
- Cannell JJ, Vieth R, Umhau JC, et al. Epidemic Influenza and Vitamin D. Epidemiol Infect. 2006; 134:1129-40.
- Carrillo AE1, Flynn MG, Pinkston C, Markofski MM, Jiang Y, Donkin SS, Teegarden D. Impact of Vitamin D Supplementation During a Resistance Training Intervention on Body Composition, Muscle Function, and Glucose Tolerance in Overweight and Obese Adults. Clin Nutr. 2013 Jun;32(3):375-81. doi: 10.1016/j.clnu.2012.08.014. Epub 2012 Aug 31.
- Ginde AA, Mansbach JM, Camargo CA, Jr. Association Between Serum 25-Hydroxyvitamin D Level and Upper Respiratory Tract Infection in the Third National Health and Nutrition Examination Survey. Arch Intern Med. 2009; 169:384-90.
- Giovannucci E, Liu Y, Hollis BW, Rimm EB. 25-hydroxyvitamin D and Risk of Myocardial Infarction in Men: a Prospective Study. Arch Intern Med. 2008; 168:1174-80.
- Gorham ED, Garland CF, Garland FC, Grant WB, Mohr SB, Lipkin M, Newmark HL, Giovannucci E, Wei M, Holick MF. Optimal Vitamin D Status for Colorectal Cancer Prevention: a Quantitative Meta-analysis. Am J Prev Med. 2007 Mar;32(3):210-6.
- Heaney, Robert P. “The Vitamin D Requirement in Health and Disease.” The Journal of Steroid Biochemistry & Molecular Biology 97 (2005):13-9.
- Holick MF. Vitamin D. In: Shils M, Olson J, Shike M, Ross AC, ed. Modern Nutrition in Health and Disease, 9th ed. Baltimore: Williams and Wilkins, 1999.
- National Institutes of Health Office of Dietary Supplements. Vitamin D: Dietary Supplement Fact Sheet. University of Ottawa Evidence-based Practice Center. Effectiveness and Safety of Vitamin D in Relation to Bone Health. Agency for Healthcare Research and Quality. Aug 2007: 07-E013.
- Salehpour A1, Hosseinpanah F, Shidfar F, Vafa M, Razaghi M, Dehghani S, Hoshiarrad A, Gohari M. A 12-week Double-blind Randomized Clinical Trial of Vitamin D₃ Supplementation on Body Fat Mass in Healthy Overweight and Obese Women. Nutr J. 2012 Sep 22;11:78. doi: 10.1186/1475-2891-11-78.
- Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized Trial of Vitamin D Supplementation to Prevent Seasonal Influenza A in Schoolchildren. Am J Clin Nutr. 2010 91:1255-60. Epub 2010 Mar 10.
- Wilkins, Consuelo H. and Yvette I. Sheline, et al. “Vitamin D Deficiency Is Associated with Low Mood and Worse Cognitive Performance in Older Adults.” American Journal of Geriatric Psychiatry 14 (2006): 1032-40.
Joseph Pritchard graduated from Our Lady of Fatima Medical School with a medical degree. He has spent almost a decade studying humanity. Dr. Pritchard writes as a San Francisco biology expert for a prominent website and thoroughly enjoys sharing the knowledge he has accumulated.