Certainly with the Crohns your diet is going to effect the degree but as for the others I have to say it is individulaiized greatly as what helps some doesnt help others at all.
There is always some everchanging advice for us nutritionally it becomes difficult to keep track of.
I do after years of trials and research add B12 to the mix of meds I take as well as try to eat foods high in B12 as it has shown a very high incident of aiding in releiving pain and supporting energy levels bogged down by the meds we are forced to take and the great amounts of time we spend inactive due to the pain and our bodies constant battle with pain levels way beyond the norm on a daily basis. I am on methadone and it has a very high ability to cause me to want to lie around and doze often and it has become alot better in the years since I have added B12 to my diet and medicine cabinet.
I thought I saw someone here that had some background in nutrition once in awhile and maybe they will chime in here and if not there is a board of nutrition that can aid you as well as a nutritionist on staff at most all county health departments that could probably help you.
Bilateral knee replacements,spondylosis of L-3,4,5 and S-1, osteoarthritis,premenopausal migraines.
Meds: Methadone,xanax,zanaflex,maxide,prempro,K+,indocin,lexapro,neurontin(coming off) lyrica(going onto)