Unfortunately, due to the highly restrictive nature of the diet, vegans are at risk of being deficient in certain nutrients such as calcium and vitamin B12 usually found in dairy and meat respectively.

One of the earliest followers of what we now consider a vegan diet was Arab philosopher and poet Al-Maʿarri who abstained from animal products for his health and beliefs on the transmigration of souls and animal welfare.

Beer and Wine Isinglass, a gelatin-based substance derived from fish, is used as a clarifying agent in some beer and wine. Other non-vegan ingredients sometimes used are casein (from milk) and egg whites.

The first thing to consider is where the hens have come from. If they have been bought from a farmer or a breeder, then by buying hens we are still contributing to the problems associated with commercial egg production, such as the male chicks being killed at birth, normally through being macerated or being gassed.