Unless you're applying to Oxbridge, Biology and Chemistry plus one other subject would suffice.*
As Biology and Chemistry are content heavy i.e. lots of stuff to remember, a subject like English Literature might allow you to take the strain off a little. Not to say you don't have to know a lot, but it's more a case of, if you know it, you know it.
Does it help? Well, it doesn't not help. Doing an essay based subject may well help your verbal reasoning and expression, which are key skills for any health professional. You will have to write reports and you will have to write literature reviews as part of a medical degree, so those skills are worth nurturing early on.*
*