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Vegan For Life
by Jack Norris, RD &
Ginny Messina, MPH, RD
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Individual Cases of Deficiency

This is a list of cases, mostly reported in the scientific literature but also some anecdotal, of severe vitamin B12 deficiency suffered by vegans. This list does not include infants and toddlers which can be found in Vegan Infants & Toddlers with Serious B12 Deficiency.


Jayaram N, Rao MG, Narasimha A, Raveendranathan D, Varambally S, Venkatasubramanian G, Gangadhar BN. Vitamin B₁₂ levels and psychiatric symptomatology: a case series. J Neuropsychiatry Clin Neurosci. 2013 Spring;25(2):150-2. | link

Of 19 patients demonstrating psychiatric illness at an Indian clinic, 14 had followed a "strict" vegetarian diet. Not many details were given, though 15 of the 19 patients had low B12 levels, defined as < 225 pg/ml.

Mavrommati K, Sentissi O. Delirium as a result of vitamin B12 deficiency in a vegetarian female patient. Eur J Clin Nutr. 2013 Jul 17. | link

62-year old woman in Switzerland, strict vegetarian, was found wandering the streets. Her delirium was determined to be vitamin B12 deficiency. She wast treated with 1,000 µg injections weekly and within 4 weeks she had regained a stable mental status and returned to full-time work.

Gürsoy AE, Kolukısa M, Babacan-Yıldız G, Celebi A. Subacute Combined Degeneration of the Spinal Cord due to Different Etiologies and Improvement of MRI Findings. Case Rep Neurol Med. 2013;2013:159649. doi: 10.1155/2013/159649. Epub 2013 Mar 27. | link

44-year old woman from Turkey. Had been vegan for 9 months. Gradually worsening paresthesia and tingling of both hands and feet for 6 weeks with a B12 level of 135 pg/ml and MCV of 110 fl. Intravenous B12 therapy was started at 1,000 µg/day for 2 weeks and once weekly thereafter. Complete clinical improvement occurred during two months and two months later there was a striking reduction of the MRI abnormalities.

Crawford JR, Say D. Vitamin B12 deficiency presenting as acute ataxia. BMJ Case Rep. 2013 Mar 26;2013. | link

Seven year old from San Diego.

De Rosa A, Rossi F, Lieto M, Bruno R, De Renzo A, Palma V, Quarantelli M, De Michele G. Subacute combined degeneration of the spinal cord in a vegan. Clin Neurol Neurosurg. 2012 Feb 6. | link

From Italy: A 36-year-old woman developed numbness, tingling and sensory loss in her hands and feet, weakness in the lower limbs, and disequilibrium, with difficulty in writing, gait, walking up and down stairs, driving. She was a dance-master, and after 3 months she was not able to work. The patient was treated with intramuscular injections of cyanocobalamin. Oral vitamin D3 and calcium were also given. After 3 months, the patient reported paresthesias and gait improvement. Six months later, weakness, sensory disorders, and paresthesias had fully disappeared, and she reported that her skin got clearer and hair loss stopped. After 1 year, spinal cord MRI, nerve conduction studies, and somatosensory evoked potentials were normal. Neurological examination, 2 years from the onset, showed reduced vibration sense in the lower limbs and normal tendon reflexes.

From a colleague, August 31, 2010:

A [animal protection organization] staffer's husband was suffering severe joint pain and fatigue to the point of not being able to get out of bed. Doctor thought it was Lyme disease, but blood tests confirmed: severe B12 deficiency. Needless to say, he didn't supplement.

Kuo SC, Yeh CB, Yeh YW, Tzeng NS. Schizophrenia-like psychotic episode precipitated by cobalamin deficiency. Gen Hosp Psychiatry. 2009 Nov-Dec;31(6):586-8. Epub 2009 Mar 27. | link

31-year old Taiwanese male. Over the course of a few years he became more and more paranoid and schizophrenic until he was admitted due to alarming paranoid behavior. At first he was placed on an anti-psychotic drug. 7 weeks later, he was back in the hospital and this time it was discovered that he had been vegetarian since his teenage years with his only source of vitamin B12 being "minimal intake of dairy products." The anti-psychotic drug was replaced with 1,000 µg per day of oral cobalamin. His state improved in 2 weeks and 1 year after discharge he had not had another episode. His B12 levels went from 136 to 227 pg/ml in the first 2 months of therapy.

Nightingale LM, Paviour DC. Nutritional optic and peripheral neuropathy: a case report. Cases J. 2009 Jun 5;2:7762. | link

Brocadello F, Levedianos G, Piccione F, Manara R, Pesenti FF. Irreversible subacute sclerotic combined degeneration of the spinal cord in a vegan subject. Nutrition. 2007 Jul-Aug;23(7-8):622-4.

57 year old male vegan with irreversible subacute sclerotic combined degeneration of the spinal cord. Hospitalized due to weakness, inability to walk, difficulty in handling utensils, constipation, and urinary retention, among other things (serum B12: 30 pg/ml, MCV: 115 fl, Hcy: 15.4 µmol/L, uMMA - 1.3 µmol/L
It's somewhat surprising that his homocysteine and urinary MMA levels weren't higher than that. The authors also mention that his diet was low in protein and calories. Upon treatment, his blood values returned to normal, but after one year he still had not regained the ability to walk.

15 Year Old Vegan Not Supplementing with B12 Develops Lameness

Chiron et al. (2001, France) reported a 15-year-old boy hospitalized because of lameness and jaundice. He had B12-deficiency anemia as well as rickets. A diet supplemented with calcium, vitamin D, and B12, and orthopedic treatment stabilized the bone lesions. The anemia was cured by a B12 injection(s). The authors state, "The adolescent and his brother were victims of a diet imposed by a cult and a lack of care due to their parents refusing that a vegan diet was the cause of the deficient pathology." The article is in French and no further information was given in the abstract.

Reference: Chiron R, Dabadie A, Gandemer-Delignieres V, Balencon M, Legall E, Roussey M. [Anemia and limping in a vegetarian adolescent] Arch Pediatr. 2001 Jan;8(1):62-5. French. (Abstract)

10 Year Old Develops Serious Neurological Problems

Cornejo et al. (2001, Spain) reported a 10 year old boy with serious neurological problems. They said the boy was as "a member of a religious community who were strict vegetarians." The article is in Spanish and no further information was given in the abstract.

Reference: Cornejo W, Gonzalez F, Toro ME, Cabrera D. [Subacute combined degeneration. A description of the case of a strictly vegetarian child] Rev Neurol. 2001 Dec 16;33(12):1154-7. Spanish. (Abstract)

14 Year Old Vegan Develops Fatigue, Aching, Stumbling, and Heart Murmur

Licht et al. (2001, USA) reported a 14 year old boy with a serum B12 of 281 pg/ml. This is not particularly low. However, he had developed fatigue, daytime sleeping, an aching calf, stumbling, and a heart murmur. He was small for his age and withdrawn. His mean corpuscular volume was 108 fl, serum MMA was 2.5 µmol/l, and homocysteine was 64.4 µmol/l. He did not have anemia. His mother considered him a "picky eater." He was treated with a number of 1,000 µg intramuscular injections of B12.Treatment resulted in normal gait, but after 18 months he still had nerve problems.

Reference: Licht DJ, Berry GT, Brooks DG, Younkin DP. Reversible subacute combined degeneration of the spinal cord in a 14-year-old due to a strict vegan diet. Clin Pediatr (Phila). 2001 Jul;40(7):413-5.

33 Year Old Vegan Not Supplementing with B12 Develops Nerve Problems and Vision Damage

Milea et al. (2000, France) reported a male vegan of 13 years who appeared to have a poor diet given deficiencies of vitamins A, B1, B12 (154 pg/ml), C, D, E, and folate, and zinc and selenium. He had been vegan for "improved health," and did not smoke or drink alcohol. He was found to have severe optic nerve disease, sensory nerve problems, reduced hemoglobin, and a 110 fl. MCV. He had no signs of malabsorption. After a multivitamin and B12 injections of 1000 µg/day for 1 week, his hemoglobin and sensory nerve problems disappeared, but his vision didn't recover. The authors concluded that "The optic neuropathy in our patient was apparently related to deficiencies of B12 and B1, but other associated deficiencies may have had a role."

Reference: Milea D, Cassoux N, LeHoang P. Blindness in a strict vegan. N Engl J Med. 2000 Mar 23;342(12):897-8.

36 Year Old Vegan Not Supplementing with B12 Develops Poor Vision

Li & McKay (2000, UK) reported a woman who was vegan for many years. She had megaloblastic anemia due to folate deficiency 6 years earlier. Her B12 levels and absorption were normal at that time. During her current visit to the clinic, she reported decreased vision during the previous week. Again, she had signs of megaloblastic anemia, but this time with low B12 level (130 pg/ml) and low folate. She was treated with oral folate and iron, and a B12 injection. Her vision returned to normal within days. Again, there were no features of malabsorption and Li & McKay concluded that her vitamin deficiencies were of dietary origin.

Reference: Li K, McKay G. Images in clinical medicine. Ischemic retinopathy caused by severe megaloblastic anemia. N Engl J Med. 2000 Mar 23;342(12):860.

80 Year Old Vegan Not Supplementing with B12 Develops Nerve Damage

Bernstein (2000, USA) describes a man in his eighties who had been in excellent health, and was a runner. He had been vegan for 38 years and attributed his ability to outperform younger people to his diet. In the span of a few weeks, mental disturbances began to set in. He cried, was confused, got lost, was incontinent, lost control of his bowels, and lost motor skills to the point where he could barely stand with help. He was diagnosed with "senile dementia." A blood test showed slightly large red blood cells. Further blood tests revealed that his B12 level was undetectable. He was given an injection of 1000 µg of B12. The next morning he could sit without help. His bladder control returned within 48 hours. By the end of the week, he could play simple card games, read get-well cards, and talk on the phone. He still cried easily and his attention span was too short to go back to work. Bernstein concludes, "[A] diet free of animal protein can be healthful and safe, but it should be supplemented periodically with vitamin B12."

Reference: Bernstein, L. Dementia without a cause. Discover. February 2000:31.

50 Year Old Vegetarian Develops Neurological Problems from Short-term Nitrous Oxide Anesthesia

Rosener & Dichgans (1996, Geremany) reported a 50-year-old vegetarian woman eating mostly apples, nuts, and raw vegetables who underwent nitrous oxide anesthesia for a hip fracture after injuring herself ice-skating. She was ventilated with nitrous oxide for 2 hours. Four weeks later, she developed rapidly increasing sensory impairment of the legs. Six weeks later, she could not walk. She was diagnosed with neurological degeneration secondary to B12 deficiency. After 5 months of treatment with cyanocobalamin injections, she could walk on crutches. At one year later, she had continued to improve. Vegetarians should make sure their B12 status is healthy before undergoing nitrous oxide anesthesia.

Reference: Rosener M, Dichgans J. Severe combined degeneration of the spinal cord after nitrous oxide anesthesia in a vegetarian. J Neurol Neurosurg Psychiatry. 1996(Mar);60(3):354.

14 Year Old Vegetarian Not Supplementing with B12 Develops Nerve Problems

Ashkenazi et al. (1987, Israel) reported a 14-year-old girl who had been vegetarian (and apparently vegan) for 8 years after witnessing the slaughter of a cow. She had been healthy previously and seemed well nourished. She had neurological problems including an unstable walk, unsteady standing with eyes closed, some impaired sensations, mildly reduced muscle strength, and reduced ankle-jerk reflex. Her serum B12 was 50 pg/ml. Absorption was normal. She had not been taking B12 supplements as her parents were unaware of the need and her doctor was unaware of her diet. Injections and supplements were given, and the girl followed advice to begin eating fish and dairy products. (This was, of course, unnecessary). A rapid improvement was noted with a complete neurological recovery after 4 months.

Reference: Ashkenazi S, Weitz R, Varsano I, Mimouni M. Vitamin B12 deficiency due to a strictly vegetarian diet in adolescence. Clinical Pediatrics. 1987;26(Dec):662-663.

Rastafarian Community

Campbell et al. (1982, Jamaica) reported 10 Rastafarian men (age 18-49) with B12 deficiency. They had been vegan 2-20 years. 8 had neurological symptoms. B12 malabsorption was ruled out in all cases. 8 had moderate to severe macrocytic anemia. 6 were jaundiced, 3 had a swollen tongue, 2 had anorexia, 1 had vomiting, 1 had abdominal pain, and there were other symptoms. Their serum B12 range was 10-130 pg/ml, with only 2 over 75 pg/ml. Their blood completely responded to cyanocobalamin injections. Of 3 who had subacute neurological degeneration, one recovered completely. Another improved considerably but had residual motor defects after several months of treatment. The third patient died of a heart attack 11 days after admission. Campbell stated, "Our patients were not very cooperative in taking oral vitamin B12 or attending the clinic for vitamin B12 injections."

Reference: Campbell M, Lofters WS, Gibbs WN. Rastafarianism and the vegans syndrome. BMJ (Clin Res Ed). 1982 Dec 4;285(6355):1617-8.

56 Year Old Vegan Not Supplementing with B12 Develops Extremely Low B12 Levels

Murphy (1981, UK) reported a male vegetarian of 40 years. He had been vegan for the previous 4 years since developing angina. He had been treated for the previous 8 years with phenobarbital for epileptic seizures. He was admitted for an aortic valve replacement and found to have low hemoglobin, a 98 fl. MCV, and 50 pg/ml B12 level. Folate was normal. A deoxyuridine suppression test showed B12 deficiency. He was treated with 5 µg B12/day, orally, for one month. His serum B12 levels rose to 205 pg/ml and his hemoglobin returned to normal.

Reference: Murphy MF. Vitamin B12 deficiency due to a low-cholesterol diet in a vegetarian. Ann Intern Med. 1981 Jan;94(1):57-8.

57 Year Old Vegan Not Supplementing with B12 Develops Nerve Problems

Carmel (1978, USA) reported on a man admitted to the hospital in 1976 with trouble walking. He had been in good health until 1972 when he retired because of fatigue. He had been almost vegan, eating small amounts of dairy, for 25 years. He had siblings who ate a similar diet, but who took B12 and did not develop problems. In 1974, a chiropractic nutritionist told him his problems were not related to a B12 deficiency. He then replaced the dairy in his diet with a raw egg yolk every other day. He improved for a short time but then got worse. Two weeks before admission, he began taking 100 µg B12/day. Upon admission, he had decreased sensation in the hands and below the knees, with slight megaloblastic anemia. His B12 level was 146 pg/ml. He was injected with 1000 µg/day of B12 for 3 weeks which caused rapid improvement. He then received B12 injections once a month for 6 months (by which time his only neurological problem was in his feet) and then he started 100 µg/day orally. He also started eating fish, dairy products, and eggs. His B12 level stabilized at about 300 pg/ml. He had slightly depressed intrinsic factor secretion and reduced stomach acid, which was apparently not due to the B12 deficiency as it did not improve with treatment. His problems were probably due to a combination of low B12 intake and decreased absorption.

Reference: Carmel R. Nutritional vitamin-B12 deficiency. Possible contributory role of subtle vitamin-B12 malabsorption. Ann Intern Med. 1978 May;88(5):647-9.