HIV Prevention With PrEP, an Ancient Microbiome, and Freezing Fat

11:54 minutes

Pre-exposure prophylaxis, or PrEP—used to prevent the transmission of HIV—is slowly gaining notice in the United States, but the treatment is not widely available in Europe. A study out this week Science Translational Medicine used models to show that nearly two-thirds of new HIV infections in gay and bisexual men in the Netherlands could be prevented with the treatment. Azeen Ghorayshi, a science reporter at BuzzFeed News, discusses this and other stories from the week in science.

Plus, can cold help you lose weight? It’s a tantalizing prospect as winter sets in, but do devices like ice-pack vests and doctor-administered fat-freezing treatments have good science to back them? STAT’s “Morning Rounds” writer Megan Thielking breaks down the good and the bad of harnessing cold for weight loss.

*The title of this segment was updated on January 14, 2016 to “HIV Prevention With PrEP, an Ancient Microbiome, and Freezing Fat.” (The original title, which is still in the URL, was “HIV Prevention With PrEP, Demystifying Diets, and Freezing Fat.” The “demystifying diets” story was not discussed in this segment.)

Segment Guests

Azeen Ghorayshi

Azeen Ghorayshi is a science reporter for BuzzfeedNews in New York, New York.

Megan Thielking

Megan Thielking is the Lead Writer for “Morning Rounds” at STAT, based in Boston, Massachusetts.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. Later in the hour, a look at the future of self-driving cars. But first, if you’re a listener to this show, when you listen long enough you know that one of our favorite topics is the microbiome. Our gut bacteria, our microbes, the trillions of them have been linked to everything from mental health, to obesity, to drug efficacy.

This week, researchers report that they dug up samples of an ancient microbiome that can offer insights into human migration. My next guest is here to tell us about that story and other selected short subjects in science. Azeen Ghorayshi is a science reporter for Buzzfeed News, here in New York. Welcome.

AZEEN GHORAYSHI: Thanks for having me.

IRA FLATOW: Let’s talk about the microbiome.


IRA FLATOW: What’s going on here?

AZEEN GHORAYSHI: So, you have to first introduce Otzi. Otzi is a 5,300-year-old frozen ice man that was found in the Southern Alps in 1991. He’s been studied a lot. So people studied his clothing, his tools, his tattoos– he’s the oldest tattooed man that we’ve dug up so far– and now they’re starting to look at his microbiome. So scientists sequenced the DNA of his entire stomach, and they found a type of bacteria called Helicobacter pylori. That’s currently found in roughly half of our guts today. And in about 10% of people it causes things like gastritis, ulcers. It can lead to cancer. But for the most part, we sort of happily coexist.

So what’s really cool about this is that not only do we now know that H. pylori has been part of our bacteria cargo for a really long time, we also can use the evolution of the bacteria to sort of trace human migrations. So the scientists looked at his particular strain and saw that it was similar to the Central and South Asian strains. Different from the modern day European strains that we’d see. And so that suggested that predecessors of early European farmers had interacted with Asians before migrating to Europe. And then later, African strains had entered, producing the modern day strains we see today.

And then, another really cool thing, I thought, was they showed that he had the immune response we see in humans for H. Pylori being there for a long time. So it was possible that he suffered from ulcers. Poor Otzi.

IRA FLATOW: Poor guy, poor guy. Let’s move on to a study in the Netherlands that looked at the HIV prevention treatment, PrEP.


IRA FLATOW: And I don’t think a lot of people have heard about that.

AZEEN GHORAYSHI: Yeah. So it’s actually a huge deal. It’s a recently developed, once-a-day pill, that when taken properly can prevent the transmission of HIV. So it’s basically pre-exposure prophylaxis, is what it’s actually called. It’s basically two meds that are used to treat HIV, so that if someone is exposed to virus, it basically can’t take hold in their bodies. And public health officials have been recommending it more and more to people, to take it as a preventive measure in the US, but it hasn’t really entered the mainstream in Europe. It hasn’t passed the regulatory bodies, it isn’t publicly available, so you have to arrange with your doctors.

So this study was done using data from 617 HIV positive men in the Netherlands, where they keep and anonymized all the health data all their citizens, and then give it to scientists to research. So this is all of the people who have been diagnosed as HIV positive, from 1996 to 2010. And from that, they could tell who contracted HIV from who, by tracing the evolution of virus.

And what they showed was– they did some clever modeling– that if half of those men had been tested annually for HIV and the positive ones had been put on treatment and the other half had been put on PrEP, roughly 66% of the infections could have been prevented. This is basically making a strong case for why PrEP should be part of the sort of gamut of things that we’re doing to tackle HIV.

IRA FLATOW: Brain training games have become very popular and are marketed as a way to keep your memory up. And one of those companies, Lumosity– which you’ve probably heard them advertising a lot, including sometimes on this program– is being sued by the FTC. Tell us.

AZEEN GHORAYSHI: Yeah. So brain games, like you said, are really popular. They’ve become popular in the last five years or so. And they claim to help people perform better at work, better at school, and also they claim to stave off memory loss. And it’s a huge market. It’s valued at around $1.3 billion. And on Tuesday, the Federal Trade Commission ordered one of these companies– which makes Lumosity– to pay $2 million to settle charges that their claims are unfounded because one of the big things is that they say they’re backed by science. The FTC said that they, quote “preyed on consumer fears about age-related cognitive decline.” They do market a lot to baby boomers, particularly stressed about dementia, and Alzheimer’s, and things like that.

So, this is huge. They basically said that their science was unfounded, and they now have to pay back the money for the people who have bought their product. And also, let the other people know that this happened.

IRA FLATOW: Now, you know the FTC going after food producers it’s not something new. It’s happened before. I mean, I’m trying to remember one of the big pomegranate juice makers a few years ago was forced to take back some of the claims that it had about longevity and implying it was almost medicine.

AZEEN GHORAYSHI: Right. And I mean, they say they’re backed by science, but a lot of the studies are done by the companies that make the products. And a lot of studies aren’t actually publicly available for people to verify. So it’s kind of a big deal.

IRA FLATOW: A lot of medicine works that way also.



IRA FLATOW: Finally, a researcher has found a possible connection between sleep apnea and heart health.


IRA FLATOW: If you’re not sleeping, with apnea it’s a certain kind of not sleeping, it’s not just insomnia, right?

AZEEN GHORAYSHI: Right, right. So yeah, sleep apnea– obstructive sleep apnea– is a disorder which causes, among other things, snoring. And it can actually increase the risk of cardiovascular disease. And this has been known for a while, but scientists didn’t really know why that link existed.

So basically, during sleep, the muscles in your airway relax. If the relaxed muscles block the airway, that can deprive you of air flow and cause you to snore. It can be kind of dangerous. So this Columbia group looked at cells that line blood vessels– where cardiovascular damage tends to start– in people with sleep apnea and without it. And they saw that, in the people with sleep apnea, they’re more vulnerable to attacks from the immune system, their cells. They’re more likely to be damaged and then they therefore obstruct blood flow. So that is sort of the link to the cardiovascular disease.

And interestingly, they showed that in the few people in their study that had sleep apnea, but were also taking cholesterol med– statins– those people actually had healthy cells. So something about that link– I mean, it needs to be investigated further– but it’s definitely something curious to look into.

IRA FLATOW: It’s always, always– sleep is something that seems to be linked to so many things, so many health things. Thank you. Thank you, Azeen, for taking time to do this today.

AZEEN GHORAYSHI: Thanks for having me.

IRA FLATOW: Azeen Ghorayshi is a science reporter for Buzzfeed News, here in New York. Now it’s time to play Good Thing, Bad Thing.


IRA FLATOW: Because every story has a flip side. Well last Friday– maybe you were one of them– the Polar Bear Swim Club members across the country rang in 2016 with a shiver-inducing ritual. That is, an icy dunk in a local waterway. And here in New York, the Speedoed and bikinied members of the Coney Island Polar Bear Club met for the 113th New Year’s swim. And this year they got off easy because the water was only 50 degrees. It was warmer than usual. But we wondered, is there a side benefit to all of that chill? Could cold help these human polar bears, so to speak, and us, shed a few pounds? Here to weigh in is Megan Thielking. She’s head writer for STAT’s Morning Rounds. She joins us today from chilly Boston.

Good day to lose weight in Boston today, Megan?

MEGAN THIELKING: You know, it’s a little chilly outside, so probably so.

IRA FLATOW: Let’s talk about it. So, is cold a good thing if you’re looking to shed some pounds?

MEGAN THIELKING: So, good news is cold does help you burn fat. And if you think about it, it makes sense because your body’s always trying to keep that even 98.6 degrees. So being cold means your body has to work harder to keep that normal temperature. But it kind of depends on what kind of fat we’re talking about burning. And research in the last 10 years has clarified exactly what fat we’re burning when we’re shivering.

It comes down to these two basic kinds of fat, called white fat and brown fat. And brown fat is the fat that’s deeper inside your body, and it’s what your body burns to burn calories. If you think about it, white fat is the kind of fat that you can pinch on your skin. And in research, it’s shown that brown fat is actually a promising target for therapies to lose weight and particularly to fight obesity.

So a study actually last month came out showing that, in mice, if you expose mice to cold repeatedly for a span of about 10 days, the cold actually changed the microbes in their gut and helped them lose weight over that 10 day span, and then a few weeks after that. So it seems like a promising avenue for research that cold changes the bacteria in your gut. It’s making a difference in your digestion. So you know, the good side is it could be possible that shivering outside is helping you burn a little more fat.

IRA FLATOW: Of course there’s got to be something bad about this too.


IRA FLATOW: I need to get cold all the time.


MEGAN THIELKING: Yeah, Yeah. Don’t embrace winter too much because it’s not really clear that cold is going to help you burn all over fat. And it varies a lot from person to person how much shivering is really going to help you lose fat. And pretty much all the options we have out there right now– like I said it’s a promising avenue for research– but all the options we have out there right now are pretty scientifically questionable.

So there’s one that’s actually performed in doctors’ offices. It’s this procedure called Cryolipolysis, and it’s like a device that looks like a little electric face exfoliator. And its held to a certain place on your body where you want to lose fat. And basically, what it does is freeze your fat cells to death. They actually die, it’s not about changing your gut microbes, it actually just kills off those cells. But it’s a slow process. It can take a few hours, and you can only use it one spot at a time. And then it actually takes weeks to months for that fat to be excreted from your body. So it’s just a very slow process, and it only works on one spot.

IRA FLATOW: So I can’t just take some ice cubes and throw it on my stomach and expect it to work?

MEGAN THIELKING: Interestingly, there are some DIY approaches to doing that, but there’s very little science behind them. There’s this whole market, that I find very interesting, for ice pack vests. Which, basically, are what you’re saying. You strap some ice cubes to your body. But the science is pretty shaky out there. They’ve really just been small trials, run by the companies themselves. But the idea is that it helps you burn all over fat because you just shivering while you sit there. But to me, that sounds very uncomfortable.

IRA FLATOW: I would rather sip ice water all day. Now, I’ve never had a nutritionist say that works, but I’m going to keep doing it anyhow.

MEGAN THIELKING: I mean, it makes sense. Thank you so much.

IRA FLATOW: You’re welcome. Megan Thielking is the lead writer from Morning Rounds at STAT in Boston.

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