Chris Kresser: I think you’re asking if you take a probiotic and then you take prebiotics, will it multiply that strain. The answer is, it depends on the strain, and it depends whether it’s a normal resident of the digestive tract and it can colonize the human digestive tract, which most probiotics can’t. Most of the probiotics that people take are transient. They just pass through, and they don’t take up residence in the digestive tract. And as I mentioned before, probiotics when taken orally don’t tend to quantitatively impact the levels of gut bacteria. Prebiotics do do that.
So in most cases, that’s not going to happen. In some cases, that may happen, but if you look at the safety profile of the probiotics that are on the market, they’re pretty solid, and I don’t think there’s a particular concern in most cases here. If you have a question in follow-up about that, Bill, go ahead and ask. It is, though, why I tend to prefer multi-strain products instead of single-strain, at least on an ongoing basis. We’ve talked about how to use single-strain for certain therapeutic purposes, and I’m in favor of that, obviously, but if we’re talking about just long term what’s the best approach for maintaining good gut flora, I would say prebiotics are more important than probiotics, and if you are going to take a probiotic, then taking one that has multiple strains in it is probably the best approach.