This is the biggie and probably the most controversial nutrition question around veganism but it need not be.
You need to ensure that you get a reliable source of vitamin B12 and that can be through fortified foods (at least two a day at different meals) or by taking supplements. In the US, the RDA recommends 2.4mcg per day, and in the UK the recommended dose is 1.5mcg per day.
So, what are fortified foods. Simply put, these have B12 added to them (just as feed given to some farmed animals also has). Examples include fortified non-dairy milks and yoghurts, nutritional yeast (known as ‘nooch’ within the vegan community!) and Marmite. If you eat these foods regularly, then you may be getting enough B12 to hit your RDA. But if this seems like it might be difficult, or you are in any doubt, then take a daily B12 supplement and worry no more.
As B12 is non-toxic there is no harm in taking higher levels if you choose to but the body only absorbs as much as it needs to so there is no point in taking high doses.
It is important to note that if you are concerned about your B12 levels, you should get them checked by a medical professional. If you are low in B12, you may have an issue with absorbing it, and regardless of how much you have in your diet, medical intervention may be required. This is relevant to everyone, regardless of their current diet.
PAGE UPDATED JULY 2020