During the previous 11 years solid remission, I have very aggressively taken supplements, especially the Linus Pauling patented mix: Lysine, vitC, vitE, and niacin/niacinamide.
And I have eaten "gut-friendly food" like yoghurt, okra, lychee fruit, sauerkraut, etc.
I have NO DOUBT:
1) VitD, especially from sunlight, has considerable gut-healing capacity
2) Supplements, in general, are very helpful but not the answer
3) AS is related to starch consumption but also the status of the intestinal tract; whatever compromises this can trigger flare episodes and whatever heals this can help eliminate symptoms.
4) I have developed considerable starch tolerance, but it took at least four years of strict diet and
5) Total abstinence from NSAIDs is required again for good gut health.
I do not know about B2/B3 beyond the fact they are somehow related to carbohydrate metabolism and also promote tissue healing and in this they utilize amino acids, so they are co-factors.
The B complex are a class of vitamins that are each very similar one to another and perhaps it is instructive, relative to niacin in particular, that the habit of smoking is extremely inimical to NIACIN--that is even a few drags on those cancer-sticks destroy all of the active niacin in circulation.
Couple this information with the observation that Crohn's Disease is 4-500% more frequent in the population of smokers (and because AS and CD are, IMHO, caused by the same thing, this has implications for AS; stated another way it would be foolish to continue such a preoccupation with a diagnosis of AS and I will expand this to ReA, Behcet's, UnDiffSpond, and others in our five arbitrary Seronegative Psoriatic Spondylarthropies).
I don't know about McCardles, sorry--but there are easily over 200 sequelae of AS and these observations can also have multiple names.
We have a stock market with perhaps over 3500 corporations listed, but that number is dwarfed by the actual number of funds (groups of stocks), so You see the permutations can be in the billions--same with names of diseases we can rack up with AS, so why not call every symptom one disease and two symptoms together call that another disease and these plus a third, well maybe that starts to look like yet another disease.
Well, I like Hippocrates' idea better. When I had AS, it was "John's AS" not fibromyalgia looking like adhesive capsulitis with occasional deQuervain's and TMJ, iritis, and renal calculi...I could go on and on but suffice it to say--
"MY NAME IS AS AND WE ARE MANY"