After The Surgery Back Vitamins / Supplements Many programs differ on their opinion of necessary vitamins following Bariatric Surgery. Studies have shown that the only necessary vitamins are a good multivitamin such as Centrum as well as a calcium supplement called Calcium Citrate. Some patients choose to implement B-12 immediately after surgery, however, our opinion is that a B-12 level can be drawn at the six month follow-up and added at that time, if needed.