Just be sure you're supplementing enough. If you've been vegan for 4 years, you're starting to enter the danger zone for running out of certain vitamins that your body stores.
B12 is the big obvious one, but you should also check out vitamins K2 and A (beta-carotene is only converted by about 70% of people), as well as carnitine, zinc, iron and iodine.
I take zinc, B12, D, K2 and algal omega-3. B12 is the big one, you're just trading diabetes and heart disease risk for stroke risk without that one. And everyone in northern climes should be taking vitamin D. Our salt is iodized.
B12 is the big obvious one, but you should also check out vitamins K2 and A (beta-carotene is only converted by about 70% of people), as well as carnitine, zinc, iron and iodine.