As with most dietary questions, vegans are split on the issue of dairy products – not so much on the question of whether or not they are acceptable, but instead for what reasons they should not be consumed.
[...]

An individual can have higher risks of developing anaemia and acquiring damages on their nervous system if they have a very low intake of vitamin B-12. B12 sources can be found reliable with B12 fortified foods including a few plant milks, soy products, breakfast cereals, as well as B12 supplements. However, vitamin B12 is micro-organism-based [...]

A vegan is a person who avoids as far as possible the use of any animal products for nourishment or for any other purpose.
Depending on one’s level of commitment this can include not using certain medicines because they are tested for safety on animals. A Vegan will not buy or use animal products whether [...]