The danger for vegans not taking B12 supplements is high homocysteine. High Homocysteine can lead to stroke and heart disease.
The accepted range for the serum level of B12 is 200-800ug and most vegans in this cross section of countries appear to be at the bottom end,around 200/300ug, and as a consequence have higher homocysteine levels.
https://www.veganhealth.org/b12/hcy
Air pollution these days is also causing higher homocysteine levels and IMO everybody,including vegans, should aim to get their B12 levels to 600/700 mark to ensure better cell methylation to counteract this pollution.
https://ajrccm.atsjournals.org/conten...3/283.full.pdf
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