You'll find people who have lived to be over 100 who are vegetarians, vegans, and omnivores. Nothing really conclusive there.
The way I look at it, if a bottle of window cleaner had a full day's supply of calcium in it, I still wouldn't drink it because most of it is poison. Just because meat has protein and iron doesn't mean you need meat to get your protein and iron. And so if you can get all of your nutrients without eating the poison around it, why not give it a shot?
I know meat tastes good. Thankfully there are wonderful meat substitutes that taste just as good or better. I really feel I've given up nothing by not eating meat anymore.
Now, you want to know if there are any health benefits to eating meat? I would ask the animal you're eating if he thinks so.