A case report was published by Jayte et al. on 2 April 2025, describing a 66-year-old vegetarian man in rural western Uganda.
This man "had adhered to a strict vegetarian diet for 5 years and presented with symptoms of fatigue, pallor and leg pain.
His vitamin B12 blood levels were extremely low: "Serum vitamin B12 was critically low at 61 pg/mL [= 45 pmol/L] [...]".
The authors recommend:
"Healthcare providers should be prepared to offer guidance on maintaining adequate B12 intake for patients following plant-based diets. This may include:
1. Education on B12-fortified foods (for example, certain plant milks, breakfast cereals and nutritional yeasts)
2. Recommendations for B12 supplementation, including dosage and frequency
3. Regular monitoring of B12 levels in at-risk individuals
4. Encouraging a varied diet that includes a wide range of nutrient-dense plant foods.
By implementing these strategies, healthcare providers can help prevent severe B12 deficiency cases such as the one presented here, while supporting patients in maintaining their chosen dietary patterns."
More great advice by the authors for health professionals:
This man "had adhered to a strict vegetarian diet for 5 years and presented with symptoms of fatigue, pallor and leg pain.
His vitamin B12 blood levels were extremely low: "Serum vitamin B12 was critically low at 61 pg/mL [= 45 pmol/L] [...]".
- His symptoms: "severe fatigue, breathlessness and frequent leg cramps over the past month. The man’s carer also observed a yellowish discolouration of his eyes (scleral icterus) over the past year, which had intensified recently. [...] Approximately 10 days before presentation, he had experienced an upper respiratory tract infection, which had resolved spontaneously without fever or other complications [not necessarily connected to his B12 deficiency]. On physical examination, the man appeared visibly pale and weak, with pronounced scleral icterus [yellowing in the conjunctiva (the clear membrane overlying the sclera); this is an early sign of jaundice]. His heart rate was recorded at 92bpm [this is quite high but not crazy; and heart rate changes quickly], and a 2/6 systolic murmur was heard during auscultation [a modest heart murmur; not a clear sign of anything]."
- Symptom improvement: He rapidly (within two weeks) improved after intramuscular vitamin B12 injection. His serum vitamin B12 levels were 325 pg/mL (= 240 pmol/L). [The authors wrote 325 ng/mL, but this must be a typo.] Additionally, his plasma homocysteine level changed from >48 µmol/L before B12 injection to 8.1 µmol/L after B12 injection. All the symptoms seemed to have improved after treatment: "Within a few days of initiating therapy, the patient reported increased energy and improved appetite. Five days into treatment, his haemoglobin increased to 6.4 g/dL and his white blood cell and platelet counts began to normalise. By the end of the second week, his pancytopenia and indirect hyperbilirubinemia had resolved. At 2-month follow‑up, he had gained significant weight and his laboratory results were within normal limits (haemoglobin 15.6 g/dL; MCV 88.2 fL; leukocyte count 6720/µL; platelets 252 000/mm3; serum indirect bilirubin 0.4mg/dL; LDH 170U/L; iron 71µg/dL; ferritin 664ng/mL; vitaminB12 325ng/mL; plasma homocysteine 8.1 µmol/L)."
- Was he vegan? It's not clearly stated if this man was vegan. His diet was quite unusual: "The man had been following a strict diet for the last 5 years, and consumed fruit and vegetables only rarely [!]. His diet primarily consisted of processed grains and legumes, with little variety in food choices [!]." This could have been due to lack of money or other reasons (this information is not given).
The authors recommend:
"Healthcare providers should be prepared to offer guidance on maintaining adequate B12 intake for patients following plant-based diets. This may include:
1. Education on B12-fortified foods (for example, certain plant milks, breakfast cereals and nutritional yeasts)
2. Recommendations for B12 supplementation, including dosage and frequency
3. Regular monitoring of B12 levels in at-risk individuals
4. Encouraging a varied diet that includes a wide range of nutrient-dense plant foods.
By implementing these strategies, healthcare providers can help prevent severe B12 deficiency cases such as the one presented here, while supporting patients in maintaining their chosen dietary patterns."
More great advice by the authors for health professionals:
Ask yourself ... "In what ways can I enhance my communication with patients about the importance of dietary history and regular vitamin B12 supplementation to prevent deficiencies, especially among those with dietary restrictions like vegetarians or vegans?"