Dan,
It's funny you should post this. I was just wondering about Alfalfa myself. I currently take a standard Centrum type multivitamin and over the last few days I have been looking into trying to upgrade to a multivitamin that is more targeted towards the needs of those with UC. One of the ones I was looking into contains Alfalfa Concentrate. (link below) It looks like Alfalfa may be helpful. I am going to look around a little bit more but so far this is my top choice.
http://www.lifesource4life.com/LS_Multi_Tablet_71.pdf