What are the benefits of taking up a vegan diet?

Depends: Eating lower on the food chain means less environmental toxicity in your food. But consider supplementation of b complex and methionine/taurine/choline.

Moral: The last few big studies have all shown no advantage or disadvantage for vegans versus omnivores in any category of illness, or in overall health or longevity when you control for the fact that they tend to have other healthy habits. There's a big moral advantage especially in the era of factory farming, with inhumane treatment of food animals.