Does surgery that removes the ileum change my nutritional needs?

Not likely: Mostly it would depend on how much of the small intestine is being removed. Rarely there could be some vitamin b deficiencies, but usually there would be enough small intestine remaining that supplements would not be necessary. Depending on how much of the small intestine is removed, sometimes there may be mild diarrhea.

Yes. Vit A, D E K: The ileum (the last 5 feet of small intestine) absorbs fats and fat-based vitamins (a, d, e, and k). These vitamins can affect wound healing, bones, vision, and blood clotting along with other functions. Usually, they don't take the entire ileum at surgery, and you can just take additional vitamins. Clearly you should get periodic blood levels.