The Symptoms of Vitamin B12 Deficiency
Michael Greger M.D. FACLM · October 21, 2020 · Volume 51
B12 deficiency is known as "The Great Masquerader."
In 1853, a bedridden vegetarian was reported to experience a remarkable recovery upon eating meat. Probably didn't help he was an opium addict, but he had been doing that for a decade. It was only after five years as a vegetarian did he end up bedridden, covered in bedsores, but a little beef and mutton and he was eventually up and about. Can't blame the poor guy, as this was nearly a century before the discovery and identification of vitamin B12, resulting in just one of six separate Nobel prizes awarded for teasing out its structure and function. One of the most dramatic events in the history of medicine was the curing of pernicious anemia, a B12 deficiency disease––an otherwise fatal disorder––with a special diet centered around calf and beef liver.
Vitamin B12 levels start to drop within months of cutting out meat. Yes, there are all sorts of benefits of adopting a more plant-based diet, but underestimating the risk of developing a B12 deficiency nullify the health benefits of a vegetarian diet, or even a diet centered around plant foods but contains meat only a few times a week. Even moderate amounts of animal products may not be sufficient to restore and maintain adequate vitamin B12 function.
Vitamin B12 is not made by plants. It's not made by animals either, but rather microbes that blanket the earth. We presumably used to get B12 drinking out of a mountain stream or well water, based on studies showing vegetarians in developing countries who drink purified water appear to be at higher risk. But now, we chlorinate the water supply to kill off any bacteria. So, we don't get a lot of B12 in our water anymore, but we don't get a lot of cholera, either—that's a good thing that we live in such a nice sanitary modern world. Vegetarians living in developing world slums appear to have fewer B12 problems. Basically, the more hygienic our meals, the less B12 we get. Our fellow great apes, like gorillas, get all the B12 they need eating their own feces; I prefer supplements.
Before getting into the nitty gritty of how much to take, how frequently, and which type is best, what are the symptoms of B12 deficiency?
What aren't the symptoms of B12 deficiency? It's known as "The Great Masquerader." It can cause everything from abdominal distention and chronic diarrhea to shortness of breath and swollen red painful feet. It can also cause Parkinson's syndrome-like symptoms, skin darkening that resolved with supplementation, and something I had never heard of before—bilateral useless hand syndrome.
The "Many Faces" of B12 deficiency include neurologic symptoms such as numbness and tingling in the hands and feet, muscle cramps, dizziness, cognitive disturbances, difficulty walking, erectile dysfunction, as well as fatigue and psychiatric symptoms like depression and even psychosis.
For example, a 47-year-old woman with a five-year history of psychosis, treated with antipsychotic drugs, cognitively impaired, reporting visual hallucinations, until finally her mother revealed that the patient was following a strict vegan diet for seven years. She started B12 supplements, and her symptoms went away. Years of her life lost in a psychotic haze, all apparently because she didn't want to take a supplement. But vitamin B12 supplementation is mandatory for anyone eating plant-based diets.
Becoming psychotic is bad, but hey, better than falling into a coma, and not to mention, suddenly going blind with multiple organ failure––all thanks to B12 vitamin deficiency on a vegetarian diet. Looking into his eyes, they saw "exuberant haemorrhages" – he was bleeding into his eyes. You don't have to be an ophthalmologist to recognize this is not what the back of your eyes should probably look like.
Gill SL. Case of an opium-eater and vegetarian becoming bedridden: recovery upon taking animal food. Lancet. 1853;62(1561):95.
Smith E. The discovery and identification of vitamin B12. Br J Nutr. 1952;6(1):295-9.
Kalita J, Misra UK. Benefit of vitamin B-12 supplementation in asymptomatic elderly: a matter of endpoints. Am J Clin Nutr. 2015;102(3):529-30.
Coller BS. Blood at 70: its roots in the history of hematology and its birth. Blood. 2015;126(24):2548-60.
Nutrition Classics. The Journal of the American Medical Association 87:470-6, 1926. Treatment of pernicious anemia by a special diet. George R. Minot and William P. Murphy. Nutr Rev. 1978;36(2):50-52.
Dinu M, Pagliai G, Cesari F, et al. Effects of a 3-month dietary intervention with a lacto-ovo-vegetarian diet on vitamin B12 levels in a group of omnivores: results from the CARDIVEG study. Br J Nutr. 2018:1-18.
Hannibal L. Invited commentary in response to: 'Identification of vitamin B12 deficiency in vegetarian Indians'. Br J Nutr. 2018;119(9):967-969.
Van dusseldorp M, Schneede J, Refsum H, et al. Risk of persistent cobalamin deficiency in adolescents fed a macrobiotic diet in early life. Am J Clin Nutr. 1999;69(4):664-71.
Mariotti F. Plant protein, animal protein, and protein quality. In: Mariotti F., ed. Vegetarian and Plant-Based Diets in Health and Disease Prevention. Academic Press; Cambridge, MA, USA: 2017. 621-42.
Gupta ES, Sheth SP, Ganjiwale JD. Association of Vitamin B12 Deficiency and Use of Reverse Osmosis Processed Water for Drinking: A Cross-Sectional Study from Western India. J Clin Diagn Res. 2016;10(5):OC37-40.
Pawlak R, Lester SE, Babatunde T. The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12: a review of literature. Eur J Clin Nutr. 2014;68(5):541-8.
Herrmann W, Geisel J. Vegetarian lifestyle and monitoring of vitamin B-12 status. Clin Chim Acta. 2002;326(1-2):47-59.
Dobrozsi S, Flood VH, Panepinto J, Scott JP, Brandow A. Vitamin B12 deficiency: the great masquerader. Pediatr Blood Cancer. 2014;61(4):753-5.
Rajsekhar P, Reddy MM, Vaddera S, Rajini G, Tikeli V. A rare case of vitamin B12 deficiency with ascites. J Clin Diagn Res. 2014;8(7):MD01-2.
Mirijello A, Vallone C, De cosmo S, Landolfi R, Addolorato G. Chronic diarrhea in a patient with severe vitamin B12 deficiency: a rare clinical manifestation. Scand J Gastroenterol. 2016;51(6):763-4.
Bhattacharjee A, Easo samuel A. Vitamin B12 Deficiency in a Patient Presenting with Dyspnea: A Case Report. Adv J Emerg Med. 2019;3(2):e19.
Budhdeo S, Rajagopal V. Bilateral red legs as a result of vitamin B deficiency. Br J Hosp Med (Lond). 2017;78(10):592.
Santos AF, Rodrigues M, Abreu P, Ferreira C. Reversible parkinsonism and cognitive deficits due to vitamin B₁₂ deficiency. Neurol Sci. 2015;36(6):1031-2.
Agarwal A, Saini AG, Attri S. Reversible Hyperpigmentation and Paraparesis: A Simple Remedy!. J Pediatr. 2018;201:294.
Biyani S, Jha SK, Pandey S, Shukla R. Acute bilateral useless hand syndrome: a rare presenting manifestation of vitamin B12 deficiency. BMJ Case Rep. 2015;2015
Wolffenbuttel BHR, Wouters HJCM, Heiner-fokkema MR, Van der klauw MM. The Many Faces of Cobalamin (Vitamin B) Deficiency. Mayo Clin Proc Innov Qual Outcomes. 2019;3(2):200-214.
Bachmeyer C, Bourguiba R, Gkalea V, Papageorgiou L. Vegan Diet as a Neglected Cause of Severe Megaloblastic Anemia and Psychosis. Am J Med. 2019;132(12):e850-e851.
Azenha C, Costa JF, Fonseca P. You are what you eat: ophthalmological manifestations of severe B deficiency. BMJ Case Rep. 2017;2017
Video production by Glass Entertainment
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Republishing "The Symptoms of Vitamin B12 Deficiency"
This is the first in a 5-video series on B12. Stay tuned for:
The Optimal Vitamin B12 Dosage for Adults
Healthiest Food Sources of Vitamin B12
The Optimal Vitamin B12 Dosage for Kids, Pregnancy, and Seniors
The Best Type of Vitamin B12: Cyanocobalamin or Methylcobalamin?
You can find all of these videos in a digital download here, along with two additional videos that will be coming out in a few months.
Another consequence of B12 deficiency may be an increase in stroke risk:
Vegetarians and Stroke Risk Factors—Vitamin B12 & Homocysteine?
How to Test for Functional Vitamin B12 Deficiency
Should Vegetarians Take Creatine to Normalize Homocysteine?
The Efficacy and Safety of Creatine for High Homocysteine
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