Difficult to get all the required proteins and vitamins from a Vegan diet so not surprising really. People on these diets can get very weird about any attempt to suggest they are endangering their health. One couple I have known for 30 plus years are now both almost immobilised because of muscle and joint problems - I want to say hey eat some meat- grissle is great, but I know they would not listen...they are too far gone- really tragic.