What's the deal with artificial sweeteners?

Dr. F. Perry Wilson (0:00)

Hi, before we start the episode, just a quick announcement that next week, we'll be doing our first Wellness, Actually grab bag episode for all the ridiculous wellness fads that don't merit a whole deep dive, but we still think they'll be a lot of fun. We'd love your help. Go to wellnessactually.fm and submit a question or comment about a fad via text or voice memo. We'd also love a social media post for us to watch. The deadline is end of day on Saturday, September 19th. So don't dally. And thanks so much. Now, here's today's episode.

Emily, I'd like you to put yourself in the mindset of an environmental investigator, all right?

Someone is leaking raw sewage into the municipal water supply somewhere upstream, and you have to figure out where it's coming from. Now, you can test the water at various points and look for different substances. So I'm wondering what kind of things you might look for in the water to kind of trace back until you see who is dumping the sewage into the local pond or river. What do you think these environmental investigators are looking for?

Emily Oster (1:14)

Chemical signatures, different strains of E coli, nice. bacterial types.

Dr. F. Perry Wilson (1:20)

Totally. Yeah. So, bacteria that are generally found in poop and stool and stuff. Definitely a big one. But not all bacteria thrive. What you really want are some chemicals that are excreted either in the urine or in the stool, are really unchanged by the environment and even better, something that's not found in nature. So I'll give you one example, which is gadolinium from MRIs. So when you get an MRI with contrast, you get gadolinium injection, you pee it out, it comes out in your urine, and it goes into the sewage, and there just ain't no gadolinium in the river water supply anywhere unless there's some sewage leaking into it. So they could use gadolinium, but it depends. Are there MRIs going on around?

One thing that they're using more and more is sucralose. Splenda.

Isn't that fascinating? Yeah, because there isn't any splenda in fresh water supplies unless it gets there by passing through someone's GI tract where it is not absorbed. This is of course what we're talking about today when we talk about non-nutritive sweeteners, artificial sweeteners. Splenda is one that just goes right, passes right through you. And increasingly, environmental investigators are using the splenda concentration gradient in fresh water to track down where the leakage is coming from.

Emily Oster (2:49)

That's gross. Does it also work with like, olin? Do you remember that? Things, speaking of things, unnatural things that just went like right through you?

Dr. F. Perry Wilson (2:57)

Yeah. I don't think, yeah, maybe.

Emily Oster (3:01)

I don't have that anymore.

Dr. F. Perry Wilson (3:02)

A University of Alberta study looked at a sweetener that's excreted in the urine. It's a sulfame. It's excreted unchanged in the urine. Nicely absorbed, excreted unchanged in the urine. And researches at the University of Alberta tested the level of this sweetener in public pools and hot tubs as a proxy.

Emily Oster (3:24)

It's fine if people pee in the hot tub, okay? It's just, it's natural.

Dr. F. Perry Wilson (3:29)

There was, it was detected everywhere. It was dramatically higher in the hot tub, everyone.

Emily Oster (3:37)

Than in the pool? Well, hot tub small, hot tub small. Okay. Guys, you might think based on this discussion that this is an episode about poop, but that was two weeks ago. Today's episode is on artificial sweeteners. So let's go.

I'm Emily Oster. I'm an economist and a data expert.

Dr. F. Perry Wilson (3:56)

And I'm Perry Wilson. I'm a medical doctor.

Emily Oster (3:59)

It's Thursday, September 17th, 2026, and this is Wellness, Actually.

Dr. F. Perry Wilson (4:04)

Because you're getting a staggering amount of health and wellness information nowadays from every source imaginable. And some of it is awesome.

Emily Oster (4:12)

And some of it is, well, actually bullsh**. Fortunately, we're both people who know how to read studies, how to parse the data, and can tell you what's worth thinking about and what you can safely ignore.

Dr. F. Perry Wilson (4:25)

But before we dig in, a note that this podcast is for educational purposes and should not be construed as medical advice. We don't know your unique situation, so talk to your doctor for personal health decisions.

Emily Oster (4:37)

This week, we're asking, what's the deal with artificial sweeteners? Perry and I will give the official smash or pass, and we'll get to your question of the week. But first, let's do the health news roundup after the break.