I'm apply to MPH programs right now and I'm unsure about what letters of recommendation to submit. Most schools want three letters of recommendation and I can definitely provide at least three. Right now, I have a rec from a professor whose global health class I got an A in and have talked to her multiple times about career opportunities, a rec from an infectious disease physician at a nearby hospital for whom I'm doing research for, and finally, a rec from my boss at my summer internship where I worked on nutrition education projects. My concern is that I don't have enough 'academic' letters, but I've been told that research can count as an academic letter? I have a meeting with my biostatistics professor soon and I was considering asking him for a letter of rec as well simply to have that additional "accademic' letter.
Does anyone know if grad schools frown upon applications with more than 3 letters of rec? Also does a letter of rec from a research advisor count as an academic letter? Essentially, I'm just trying to figure out whether I really need this additional letter from my biostatistics professor.