I'm no expert and nor as far along as you but my Dr's are really serious about taking vitamins. The concern of course is for your major organs to function at peak efficiency while you are not absorbing less from your food. Vitamins don't have to be expensive, even a couple of Flintstone chewables a day are better than nothing.
I take a multi vitamin twice a day and calcium 3 times a day, I want the best outcome long term. Please call your Dr and check what they say.