I know this thread hasn't been posted in for a few weeks but I also wanted to say along with @Arabesque and @ms.sss that I haven't taken my vitamins in quite a while. I took them for about a year, give or take a few months, after my sleeve surgery. I had my blood tested recently and everything was good for me as well. I'm sure it won't apply for everyone but for a lot of people, myself included, I would think that when you are able to eat a normal amount of food again following the surgery, as long as you are eating a balanced diet then you are probably getting all the nutrients you need. Of course, I am not a doctor though and everything I say should be taken with a very large grain of salt!