I'm aware German doesn't have a gerund like the English language does, so I was just wondering how you could translate "being a" as in "being a vegetarian may cause health problems"?
Would "als" work here?
As @Em1 correctly explained
In your example "being a vegetarian may cause health problems," you'd need to resort to a different expression, e.g. change the phrase "being a vegetarian" to "to live as a vegetarian" or "life as a vegetarian":
It's a different thing with e.g. "being a chef, he knew how to make lasagna," where you can indeed use "Als X":