What subject should I take for PRE-MED?

I really want to study medicine abroad (I want to become a doctor) so i've been researching universities in the UK and the US and apparently in the US you need to do an undergrad degree and then go off to medical school whereas in the UK you go straight to med school. I don't want to close any doors so I still want to look into the us even though there's added years of schooling.

What subjects do you recommend taking for pre-med? Biology, Chemistry or Biochem? Or does it really matter what subject you take?