Some have said that the admissions office LIKES to see non science majors apply to their school.
Think about it...80% of your applicants are Biology, Chemistry, Biochemistry, and Psychology majors...your ears probably perk up when you see an Art major, History major, or Spanish major. 😉
Agreeing with the other responses, do what fits YOU. As long as you can go into an interview with all the prerequisites, you are all set. Personally, I was a Biology major and I feel that the curriculum that I had really prepared me well for what I am studying now. But I don't think non-science majors are at a significant disadvantage, particularly if they really work hard at their sciences courses while in college.
Most importantly, make sure that when you graduate and look back on college you are happy with the choices you made in classes.
Personal choices are another matter. 🙄