I'm sceptical because of the way the documentary is cut - there's no way of knowing if the things his interview subjects say are taken out of context. There are a lot of articles on the web criticising this documentary and they make some good points. That's not to say there aren't health benefits to a vegan diet (I wouldn't really know). And I would encourage any- and everyone to eat less meat and dairy products. They're terrible for the environment and farm animals are rarely treated very well. There is a lot of good vegan or vegetarian food - but it can take some effort to find the things you like.
Thanks for caring about our health, Dr. Leslie