I'm a non-trad pre-dent student (35 years old) with an MBA and going back to retake some 20-year-old sciences and then some for prereqs - I can tell you what my prehealth advisor told me, that yes, an MBA will help my chances as many schools are less interested in admitting biology and chemistry aces and are more interested in a well rounded education especially a background that includes business school... (i guess because it shows some aptitude towards running your own practice?) But she also told me that I needed to do very well (all A's and maybe a B or 2 at most) in the sciences I a retaking. And of course a good DAT score.