Unless you are taking a LARGE number of vitamins per day then packing them in a seven day container will be just fine.
I also suggest that you put them in your carry on rather than your checked baggage. It is possible that your baggage could be lost and your vitamins with them. You "could" take the labels off the bottles and put them in your carry on in the, unlikely, event there is a question.
I have cruised around fifteen times since 9/11/01 and have never had a problem with any medication that has been in a seven day pill container. These have all been prescription medications. However I do take the prescription labels with me for all prescription medications.
The only thing that has ever been questioned were injectable medications.