Is it a possibility that taking pill-forms of probiotics can contribute to SIBO?
There is no reason they should. But if they have a lactose or similar base they could pose problems for some people, including excess gas formation.
The fermented foods don't have this ability, but it is suspected that the pills do:
Quote from the SCD:
"Elaine said that bifidus was one of those strains that tended to overgrow in an already unbalanced gut and that's why it's not allowed on SCD."
That makes no sense at all. The Bifidobacterium, including Bifidobacterium bifidus, are BENEFICIAL bacteria. Like the Acidophilus species Bifidobacterium help to control pathogenic species of bacteria and fungal Candida in the intestines.
They are also overlooking the fact that Bifidobacterium bifidus can be found in some cultured foods.