SACHA PFEIFFER, HOST:
The gut microbiome is getting a lot of attention in wellness circles and on social media. These are the trillions of microbes that populate our intestines. Scientists know they influence our health in many important ways, and there's a lot of hype out there about how to fix or optimize your microbiome. NPR health correspondent Will Stone is here to help us sort out what we need to know. Hi, Will.
WILL STONE, BYLINE: Hey there.
PFEIFFER: Could you first tell us, how do we know if we actually have a healthy microbiome?
STONE: Yeah, it can actually be tough to know, and that's because scientists are still figuring out how to even define what is healthy. There's no straightforward metric like there is for cholesterol or blood pressure. That said, we do have clues. So remember, your microbiome is this vast ecosystem inside of you. So you can look at the diversity of organisms in there, or you can look at how resilient it is in the face of disruption. Does it bounce back well? And there are certain groups of bacteria associated with better health. But researchers emphasize, it's not as simple as good versus bad microbes, though if you look online, it can be framed that way, and you can even buy a special gut microbiome test to suss that out.
PFEIFFER: Right. And those tests, how useful are they? And what do they tell us?
STONE: At this point, they're really not all that helpful. These aren't tests your doctor orders to look for a specific pathogen making you sick. These are commercially available. They usually run a few hundred dollars. They measure all kinds of microbes if you send in a stool sample. I asked doctor Alexander Khoruts about them. He's a physician researcher at the University of Minnesota.
ALEXANDER KHORUTS: I think the message the patient gets, well, gee, my doctor never did this kind of testing. This looks very impressive. It must mean something. And the reality is, unfortunately, it's not very informative at all.
STONE: There are multiple reasons for that. I mean, as we said, it's hard to interpret these because we don't have a universal definition of healthy. But beyond that, research shows the results can vary substantially depending on which test you use.
PFEIFFER: So, Will, given then the possible limits of the tests, how much merit is there to the idea that we need to fix or somehow improve our gut microbiome?
STONE: So there are clearly aspects of our modern lifestyle which are not great for our gut microbiome. There's overuse of antibiotics. A big one, of course, is our diet. I spoke to doctor Fergus Shanahan, who's at the National University of Ireland in Cork. He says people should realize we evolved with our microbiome. So it thrives when we, the host, are healthy, meaning the best things you can do are pretty simple - exercise, adequate sleep, eating whole foods, not a lot of process stuff that's low in fiber. Here Shanahan.
FERGUS SHANAHAN: Your mother probably told you all these things in different language, but all the things you were ever told, they're all good for your microbiome as well. There isn't any need for some health guru to come along and say, oh, I've got some major potion now that's going to improve your microbiome.
STONE: Now there are certainly tons of products out there being marketed in this way, and there is evidence, for example, that certain strains of probiotics can be useful in specific circumstances, say for reducing the risk of diarrhea from antibiotics or for preterm infants at risk of complications. But Shanahan says, generally, the data don't support the idea that the average healthy person benefits from taking these.
PFEIFFER: Will, could you leave us with a few tips for anybody who wants to make changes today for their gut health?
STONE: Yeah, the number one thing is fiber. Most of us don't get enough. All the experts I interviewed stressed people should eat more. They should try to get different types of fiber. And if they like, they can go for fermented food because there's evidence that can be particularly beneficial.
PFEIFFER: That's NPR health correspondent Will Stone. Thank you.
STONE: Thank you. Transcript provided by NPR, Copyright NPR.
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