We get this question all the time in comments, so here's something to refer to next time someone says something dumb, like, "great, gonna bake brownies with potato starch next time."
You have to take it raw. This means, stirred into any cold or warm beverage or food of your choosing. If you take it with any of the foregoing that's fermented and let it sit for just a while, here's what happens:
NSFW: Probiotic Bacteria Fucking Resistant Starch Granules
That's right. Most probiotics die in the stomach and small intestine giving you expensive shit. FODMAP and other fermentable fibers do their thing when they get there. Resistant starch is the only prebiotic I'm aware of that actually gives probiotics a bus ride to the colon. Speculative, but I have an idea that they might help with small intestine bacterial overgrowth (SIBO) by gradually having those bacteria attach and get taken down to the colon (where they belong) via normal bowel function. That's why I think it's good to take your potato starch sometimes on an empty stomach with just water.
What happens when your get bacteria get fed? Lots and lots and lots of things. You'll have to read up.
...Anyway, you can't cook this stuff.