Yes it is in the SF category. It does constipate, though, as per my GI doctor. All starches do, she has told me a couple of times, although they do feel good (don't cause painful cramps). Also, we IBS-ers can't really eat fatty things, so we are left with the starches. We can't otherwise but eat them (or starve).
That's why you have to also eat some IF with the SF/starchy foods Not just because of the vitamins, but also to have a normal BM schedule.