If you've got a knack for writing good stories then creative writing.
If you're more of a research/ experiment then write about it then non-fiction.
If none of those fit your description then health journalism might just be for you. 😛
It really doesn't matter. That being said, having taken a good comp class will be helpful for your college career, research, PS, MCAT writing section, etc., and a lit course may help w/ the VR on the MCAT....