December 6, 2025 • 20 mins
Coffee may nudge biology, but only within limits. We dig into new research suggesting that three to four cups a day align with longer telomeres for people with severe mental illness, then challenge the hype with the caveats that matter: observational design, smoking as a confounder, wildly different cup sizes and brew methods, and the reality that more caffeine can erase potential benefits. We translate the science into practical guidance—why moderation beats megadoses, how 400 mg per day became a sensible upper bound, and where sleep and stress fit into the bigger picture of healthy aging.
Then we pivot to a feline mystery that spans millennia. Long before house cats padded through Chinese homes, leopard cats were the stealthy mousers around early settlements, drawn by grain and the rodents it attracts. Using mitochondrial DNA from ancient remains—paired with clues from art—we trace the species shift around the eighth century as domestic cats, descended from the African wildcat, traveled the Silk Road and found their place beside people. Tameness, tolerance, and a knack for living close to humans helped them outcompete their wild cousins in a world reshaped by trade and urban life.
Across both stories runs one thread: human routines create niches that biology rushes to fill. Our cups change our days at a cellular level, and our granaries and roads alter which animals share our spaces. If you love clear science, a bit of myth-busting, and the unexpected link between breakfast and ancient history, you’ll feel right at home here. If this resonated, follow the show, share it with a friend who loves coffee or cats, and leave a quick review—what surprised you most?
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
SPEAKER_01 (00:09):
Hello, science enthusiasts.
I'm Jason Zakowski.
SPEAKER_00 (00:12):
And I'm Chris Zikoski.
SPEAKER_01 (00:14):
We're the pet parents of Bunsen, Beaker,
Bernoulli, and Ginger.
SPEAKER_00 (00:18):
The science animals on social media.
If you love science and you lovepets, you've come to the right
spot.
So put on your safety glassesand hold on to your tail.
SPEAKER_01 (00:29):
This is the Science Podcast.
Hello and welcome back to theScience Podcast.
It's episode 35 of season seven.
We hope you're happy and healthyout there.
Chris, how are you doing?
SPEAKER_00 (00:42):
I'm fantastic.
How are you?
SPEAKER_01 (00:44):
Are you enjoying this frosty weather we've had
the last day or two?
SPEAKER_00 (00:48):
Absolutely not.
I went for school yesterday andit was nice out.
And then I came home from schooland I was drive I was I was
walking to my vehicle and Ithought, what happened to the
nice weather?
Warm weather.
And when I say warm, I don'tmean warm.
It was probably minus five.
And by the time I got to myvehicle at the end of the day,
(01:10):
it was likely minus 20 degreesCelsius.
And I was very sad.
I wanted to have a nice weekendwith warm.
Again, the operative word iswarm, but it's not warm.
It's cold, but warmer than minus20.
And I think my wish was notmeant to be.
SPEAKER_01 (01:30):
No.
No, it's not a bunch and it isvery cold.
We have a parade today thatwe're in.
I don't know how well that'sgonna go, but we're gonna try
our best.
Maybe we should put Beaker snowpants on.
I don't know.
SPEAKER_00 (01:43):
That's what I suggested earlier is for Beaker
to wear her snow pants.
SPEAKER_01 (01:47):
Anyways, what's happening on the Science podcast
this week?
We have two science articles.
The first one is about howcoffee intake may help with
biological aging.
It's interesting.
And you and I both love coffee,so of course I want to be team
coffee, so I did a little deepdive into this article.
And the pet science one is aboutancient cats in China.
(02:11):
Were they the cats like we havehere, or were they a different
species?
All right, let's get on with theshow.
There's no time like ScienceTime.
This week in Science News, it'sall about how coffee intake may
help your biological aging.
SPEAKER_00 (02:28):
But don't get too excited if you're a coffee
drinker.
There are some limitations tothis study where it was an
observational design and itwhich cannot prove cause and
effect.
But we're gonna get into thatlater.
But that's just a little bit ofa disclaimer.
If you're like, whoa, I'm gonnago to my Starbucks or my Tim
Hortons or my second cup andload up on the coffee.
SPEAKER_01 (02:52):
Or circle K, or maybe just make it at home for
pennies on the dollar.
SPEAKER_00 (02:59):
Oh, I guess so.
SPEAKER_01 (03:02):
Okay.
The study comes from BMJ MentalHealth, and the findings were
published there.
The long and short of it is thatdrinking three to four cups of
coffee per day may help slowbiological aging in people with
severe mental illness.
So I did leave the severe mentalillness out.
That's what they were lookingat.
(03:23):
There were no benefits whencoffee intake exceeded four cups
per day.
I probably have on the averageday three to four cups.
Easy.
And you do too, because you havea massive mug of coffee every
morning.
That's seven cups of coffee.
SPEAKER_00 (03:38):
I don't think so, but I think it is equivalent to
three to four cups.
But I need a big cup of coffeein the morning and I drink it
all day, and it's cold by theend of the day.
I know you do, but I drink itall day.
SPEAKER_01 (03:53):
I put mine in a Stanley thermos.
Like we make a pot of coffee.
I have a very small cup ofcoffee in the morning, and then
you have your giant cup ofcoffee, and then I take the
extra in my thermos, and that'swhat I drink.
I have two or three more cups ofcoffee in the morning when I'm
teaching.
Oh, I look forward to those cupsof coffee while I'm teaching so
(04:16):
much, and the kids think it's soweird, but I don't care.
Anyways, we should probably getback to the study.
What this study found was thatthe level of intake is
associated with longertelomeres, which is a marker of
cellular aging.
Chris, why do telomeres matter?
SPEAKER_00 (04:32):
Telomeres matter because they are like protective
caps at the end of chromosomes,similar to plastic tips on
shoelaces.
And I when I read this study, Ithought about that.
And I thought about littlebricks playing with my shoelace
or playing with my hoodiestring.
And I'm like, please don't eatoff my plastic protector because
those are, you know, worth theirweight in gold.
(04:54):
Telomeres naturally shorten withage, which contributes to
cellular aging.
And telomere shortening actuallyoccurs faster in people with
major psychiatric disorders likeschizophrenia or bipolar
disorder.
Also, a little bit more abouttelomeres, they're highly
sensitive to environmentalinfluences, diet, and stress and
(05:19):
inflammation.
SPEAKER_01 (05:21):
So the idea that aging occurs more rapidly in
those with mental disorders isvery well understood.
But also the hypothesis was thatmoderate coffee intake could
slow those telomere shorteningsbecause coffee has some good
health effects as well.
So the data came from theNorwegian top thematically
(05:44):
organized psychosis study from2007 to 2018.
There was 436 adults, and 259had schizophrenia, 177 had
affective disorder.
That's like what you mentioned,like bipolar disorder, major
depressive disorder, andpsychosis.
The participants self-reportedtheir coffee consumption and
were grouped into zero a day,one to two, three to four, and
(06:07):
five or more.
And then additional informationcollected were things like
smoking habits and years smoked.
The participants drinking fivecups per day were generally
older.
And individuals withschizophrenia tended to drink
more coffee with those thanthose with affective disorders.
If you're interested aboutsmoking, 77% of them were
(06:29):
smokers, and their averagesmoking history was nine years.
And heavy coffee drinkers smokedsignificantly longer.
Smoking influences caffeinemetabolism, which can affect
results.
So they wanted to include thatin previous studies.
There's a lot of correlationbetween if you smoke, you have
way more coffee in your day.
SPEAKER_00 (06:47):
They looked at the telomere measures and how they
measured telomere length wasusing white blood cells from
blood samples.
And the results across thecoffee group actually formed a
J-shaped curve.
So the people who drank three tofour cups per day had the
longest telomeres, zero cups perday had the shorter telomeres,
(07:11):
and more than five cups a day,bye-bye benefit.
The benefit disappeared.
Interestingly, participants thatdrank four cups per day showed
telomere lengths equivalent tobeing five years biologically
younger.
And the associations actuallyremained after adjustments for
age, sex, ethnicity, whether youwere a smoker or not, the type
(07:34):
of mental disorder, and also thecurrent medications or
treatments that you were takingor that the person was taking.
SPEAKER_01 (07:41):
Some of the reasons coffee might have had this
protective effect was itcontains antioxidants and
anti-inflammatoryphytochemicals.
These phytochemicals may reduceoxidative stress.
Oxidation, of course, leads todamage and leads to the telomere
shortening.
Telomeres are highly vulnerableto both oxidative stress and the
(08:02):
inflammatory process.
So any way you can lessen those,your telomeres are not as
damaged.
So the authors of the studyproposed that moderate coffee
intake may help counteractfactors that accelerate aging in
psychiatric conditions.
And as you mentioned, Chris,there were some limitations to
the study.
So don't go out and startquaffing a bunch of coffee and
(08:23):
thinking you'll live forever.
SPEAKER_00 (08:25):
Absolutely.
So the observational design,again, cannot prove cause and
effect, but they were missingpretty detailed information.
What type of coffee was beingused or drunk?
Was it filtered, espresso?
Was it instant coffee?
Did the time of day of theconsumption make a difference?
You know what?
All coffee isn't necessarilycreated equal.
(08:47):
What was the exact caffeinelevels per cup?
But also you could be drinkingother caffeinated beverages.
There are some pretty highlycaffeinated beverages out there
on the market that may have hadeffect as well.
Results also could be influencedby lifestyle factors, medication
effects, and the interactionwith smoking.
SPEAKER_01 (09:09):
So coffee consumption worldwide is pretty
common, and studies seem to showit is beneficial in moderation.
So go coffee, but excess intakemay increase oxidative stress
and start to damage yourtelomeres.
So generally, the advice is tostay at four cups of coffee or
(09:29):
less.
SPEAKER_00 (09:31):
But really, the measurement is 400 milligrams of
caffeine per day, which you canget from other caffeinated
source sources.
SPEAKER_01 (09:39):
Now, they also didn't account for how much
creamer you put in your coffee.
SPEAKER_00 (09:44):
No, they didn't.
SPEAKER_01 (09:45):
I know somebody who doesn't drink black coffee.
SPEAKER_00 (09:48):
Interesting.
And the other thing I wasthinking about was diet, high in
processed foods.
That could be something that isharmful to the body, but that
isn't part of this study.
But it makes me think about whoyou are, what you eat, and drink
from your head to your feet.
SPEAKER_01 (10:03):
Coffee keeps me on my feet.
I'll tell you that.
I don't know where it's I don'tknow where I'd be without
coffee.
All right, that's science newsfor this week.
This week in Pat Science, we aregonna look at the house cats of
ancient China, because a newstudy came out that was really
interesting in cell genomics.
(10:24):
Early, early cats in China.
And we are going through earlylife cycle cat in our house.
That's Bricks.
SPEAKER_00 (10:33):
He's a kitten.
I've never had a kitten before,I don't think.
Like that I've been taken careof all by myself.
With you, of course, absolutelywith you.
But raising a kitten from akitten, it's been a lot and
quite a steep learning curve,that's for sure.
SPEAKER_01 (10:47):
Yeah, but it's got a steep learning learning curve,
and then it plateaus becauselike Bricks uses his litter box.
Like that is a huge dealcompared to a puppy.
And Bricks is like prettyindependent now.
Like, honestly, he can probablysurvive all around our house
where you would never leave apuppy that long young,
(11:11):
unsupervised randomly in yourhouse.
We still watch Bricks everybody,but like he can jump around and
he can get places and he cansleep places.
I don't think he's destructive.
Maybe some cats are, but not thesame way a puppy might eat
something and cause a problem.
SPEAKER_00 (11:27):
Like Bernoulli.
SPEAKER_01 (11:28):
Yeah, like Bernoulli.
We had to watch that guy like ahawk.
He ate everything.
He still does.
SPEAKER_00 (11:32):
And we still do.
He still does.
It's not I don't know.
Maybe by the time he's two,maybe that'll be the golden age.
SPEAKER_01 (11:40):
All right.
So in this study, house catsapparently arrived in China
around the 8th century AD.
But China was not cat-freebefore then.
There was a different speciesfilling the ecological niche.
New genetic evidence from thestudy reveals that leopard cats
lived alongside humans in China5,400 to 2,000 years ago, likely
(12:06):
helping with rodent control.
So that's the cool part.
It was not the domesticatedhouse cat.
What the heck are leopard cats?
SPEAKER_00 (12:16):
They're super cute.
They're small, and they'respotted wild cats that are
native to Asia.
And they likely began frequentlyancient human settlements to
hunt the rodents attracted tothe stored grain.
And so this relationship canresemble commensalism, where
animal where the animals wherethe cats benefited from humans
(12:41):
without being fullydomesticated.
Now, before you think that theywere cuddly, these early feline
visitors were probably notcuddly or tame like modern house
cats, but they exploited thesituation by living near humans
(13:02):
when it was advantageous tothem, but not seeking human
affection or to becomedomesticated.
So where there's humans, there'swaste or food and the rodents
like that as a food source.
SPEAKER_01 (13:19):
So these leopard cats just slunk about and ate
the mice that were around thehuman settlements?
SPEAKER_00 (13:27):
I'm not sure.
I wasn't living 5,400 years ago,but the study seems to link
human activity like that to theleopard cats hanging about.
SPEAKER_01 (13:36):
They'd be nice to look at.
How big are leopard cats?
Do you know?
SPEAKER_00 (13:45):
No.
SPEAKER_01 (13:46):
I just Googled that.
Are small, yeah, they are small.
They're like four to fifteenpounds.
So they're not any big yeah,they're small smaller than some
cats.
House cats.
That's crazy.
Okay.
Yeah, they're yeah, they gotlong legs.
They're roughly the size of acat, like a house cat.
Interesting.
(14:07):
Anyways, the house cats we knowof descended from the African
wildcat, not the leopard cat.
And that cat stuck around Africaand then went north to the
fertile crescent.
That's where it did really wellin the deserty areas there.
And there's been a long debateover when domestic cats got to
China.
In this study, they identifiedthat some remains in China dated
(14:30):
back to 730 AD, the TangDynasty.
Now, these cats probably werebrought by way of the Silk Road
along the trade routes.
The Chinese traders went westand saw some cute little kitties
and brought them back.
The genetic markers in alldomestic cat remains point to
Middle Eastern origins,consistent with those of the
(14:52):
spread of this domesticated catof that area.
SPEAKER_00 (14:56):
So the researchers analyzed mitochondrial DNA from
22 ancient cat remains, and thesamples range from 5,400 years
ago, the Neolithic age, to the20th century.
And what they found is that thepre-AD 200 remains contained
(15:20):
leopard cat MT DNA.
And after 730 AD, it was housecat MT DNA.
And so what that does is itsupports a species shift from
the leopard cat to the domesticcat over time.
And I'm super excited.
(15:40):
We've sent away Bricks' DNA tosee what kind of cat he is or
what region he is from.
SPEAKER_01 (15:48):
Yeah, they also use beyond the DNA, which is
interesting, the DNA from aroundthe Tang dynasty shows white fur
and short fur.
And art from that time matchesthis, which is cool.
So they used anthropology ofartifacts to match it to the
DNA.
And 85% of all the cats paintedduring that time had some white
(16:10):
fur.
So those paintings helpreconstruct what early Chinese
domestic cats looked like.
And any art before that time,like during the Han Dynasty, the
cats definitely look more likeleopard cats.
They're the art depicted aspotted cat with a long striped
tail and tall legs.
So these are like those earlyvillage cats that weren't really
(16:32):
pets but were hanging around.
I think that's cool.
They've cross-referenced thescience with anthropology, which
is itself a form of science.
SPEAKER_00 (16:40):
Mm-hmm.
That is really cool.
Because it I guess it paints abroader picture of history.
Leopard cats actuallydisappeared from human sites
around the third century AD, andthere was some possible reasons
for that.
It could have been because itwas a chaotic historical period,
lots of lots of welfare, aneconomic decline, and
(17:03):
fluctuations in population,which could have impacted the
changes in the available foodfor them.
Stability returned, and thedomestic cat had already arrived
and competed more successfullybecause they were more tame and
they were more compatible withliving directly alongside
(17:24):
humans.
One thing I love about Bricks isthat he comes in and he snuggles
and he's he likes humanaffection.
So yeah.
And so domestic cats eventuallyreplace the leopard cats in that
ecological role.
SPEAKER_01 (17:42):
So I guess as we close, interestingly, in this
study, it just shows what weknow.
Animals will adapt to humanenvironments when there's a
benefit to them, where thebenefit might outweigh some of
the dangers or the costs.
And you remember when we talkedto the hummingbird spy
scientist, there's hummingbirdsthat have evolved to live within
our human environments.
(18:02):
So that's cool too.
SPEAKER_00 (18:05):
I know, but I really want to see uh nest with the
tiny eggs.
And I he stu he studieshummingbirds, he hangs out with
hummingbirds all the time.
And when I said to him, Hey,have you ever seen a hummingbird
nest?
He said no.
And I thought, that'sinteresting.
SPEAKER_01 (18:22):
Yeah, they're just so tiny.
SPEAKER_00 (18:24):
They're just so tiny, you blink and you miss
them.
SPEAKER_01 (18:26):
Yeah.
But we're talking about cats,not hummingbirds.
SPEAKER_00 (18:29):
That's right.
And we don't want cats to eathummingbirds.
Here's a spoiler leave your catinside.
SPEAKER_01 (18:35):
Yeah.
Ginger's very cute, but she'sdefinitely more leopard cat than
a domestic cat because she's notas friendly as bricks.
No, that's not true.
She can be affectionate too.
SPEAKER_00 (18:45):
On her own terms.
SPEAKER_01 (18:46):
On her own terms.
All right, that's pet sciencefor this week.
That's it for this week's show.
Thanks for coming back weekafter week to listen to the
Science Podcast.
And a shout out to all the topdogs.
That's the top tier of ourPatreon community, The Popack.
You can sign up in our shownotes.
All right, Chris, let's hearthose names that are part of the
top dogs.
SPEAKER_00 (19:06):
Amelia Fete, Re Oda, Carol Hainel, Jennifer
Challenge, Linnea Janet, KarenCronister, Vicky Oteiro, Christy
Walker, Sarah Bram, Wendy,Diane, Mason and Lou, Helen
Chin, Elizabeth Bourgeois,Marianne McNally, Katherine
Jordan, Shelly Smith, LauraSteffenson, Tracy Leinbach, Anne
(19:29):
Uchida, Heather Burbach, Kelly,Tracy Halbert, Ben Rather,
Debbie Anderson, Sandy Brimer,Mary Rader, Bianca Hyde, Andrew
Lynn, Brenda Clark, BrianneHaas, Peggy McKeel, Holly Birch,
Kathy Zirker, Susan Wagner, andLiz Button.
SPEAKER_01 (19:48):
For science, empathy, and cuteness.
unknown (20:00):
Hopefully.
Hello, science enthusiasts.
I'm Jason Zakowski.
SPEAKER_00 (00:12):
And I'm Chris Zikoski.
SPEAKER_01 (00:14):
We're the pet parents of Bunsen, Beaker,
Bernoulli, and Ginger.
SPEAKER_00 (00:18):
The science animals on social media.
If you love science and you lovepets, you've come to the right
spot.
So put on your safety glassesand hold on to your tail.
SPEAKER_01 (00:29):
This is the Science Podcast.
Hello and welcome back to theScience Podcast.
It's episode 35 of season seven.
We hope you're happy and healthyout there.
Chris, how are you doing?
SPEAKER_00 (00:42):
I'm fantastic.
How are you?
SPEAKER_01 (00:44):
Are you enjoying this frosty weather we've had
the last day or two?
SPEAKER_00 (00:48):
Absolutely not.
I went for school yesterday andit was nice out.
And then I came home from schooland I was drive I was I was
walking to my vehicle and Ithought, what happened to the
nice weather?
Warm weather.
And when I say warm, I don'tmean warm.
It was probably minus five.
And by the time I got to myvehicle at the end of the day,
(01:10):
it was likely minus 20 degreesCelsius.
And I was very sad.
I wanted to have a nice weekendwith warm.
Again, the operative word iswarm, but it's not warm.
It's cold, but warmer than minus20.
And I think my wish was notmeant to be.
SPEAKER_01 (01:30):
No.
No, it's not a bunch and it isvery cold.
We have a parade today thatwe're in.
I don't know how well that'sgonna go, but we're gonna try
our best.
Maybe we should put Beaker snowpants on.
I don't know.
SPEAKER_00 (01:43):
That's what I suggested earlier is for Beaker
to wear her snow pants.
SPEAKER_01 (01:47):
Anyways, what's happening on the Science podcast
this week?
We have two science articles.
The first one is about howcoffee intake may help with
biological aging.
It's interesting.
And you and I both love coffee,so of course I want to be team
coffee, so I did a little deepdive into this article.
And the pet science one is aboutancient cats in China.
(02:11):
Were they the cats like we havehere, or were they a different
species?
All right, let's get on with theshow.
There's no time like ScienceTime.
This week in Science News, it'sall about how coffee intake may
help your biological aging.
SPEAKER_00 (02:28):
But don't get too excited if you're a coffee
drinker.
There are some limitations tothis study where it was an
observational design and itwhich cannot prove cause and
effect.
But we're gonna get into thatlater.
But that's just a little bit ofa disclaimer.
If you're like, whoa, I'm gonnago to my Starbucks or my Tim
Hortons or my second cup andload up on the coffee.
SPEAKER_01 (02:52):
Or circle K, or maybe just make it at home for
pennies on the dollar.
SPEAKER_00 (02:59):
Oh, I guess so.
SPEAKER_01 (03:02):
Okay.
The study comes from BMJ MentalHealth, and the findings were
published there.
The long and short of it is thatdrinking three to four cups of
coffee per day may help slowbiological aging in people with
severe mental illness.
So I did leave the severe mentalillness out.
That's what they were lookingat.
(03:23):
There were no benefits whencoffee intake exceeded four cups
per day.
I probably have on the averageday three to four cups.
Easy.
And you do too, because you havea massive mug of coffee every
morning.
That's seven cups of coffee.
SPEAKER_00 (03:38):
I don't think so, but I think it is equivalent to
three to four cups.
But I need a big cup of coffeein the morning and I drink it
all day, and it's cold by theend of the day.
I know you do, but I drink itall day.
SPEAKER_01 (03:53):
I put mine in a Stanley thermos.
Like we make a pot of coffee.
I have a very small cup ofcoffee in the morning, and then
you have your giant cup ofcoffee, and then I take the
extra in my thermos, and that'swhat I drink.
I have two or three more cups ofcoffee in the morning when I'm
teaching.
Oh, I look forward to those cupsof coffee while I'm teaching so
(04:16):
much, and the kids think it's soweird, but I don't care.
Anyways, we should probably getback to the study.
What this study found was thatthe level of intake is
associated with longertelomeres, which is a marker of
cellular aging.
Chris, why do telomeres matter?
SPEAKER_00 (04:32):
Telomeres matter because they are like protective
caps at the end of chromosomes,similar to plastic tips on
shoelaces.
And I when I read this study, Ithought about that.
And I thought about littlebricks playing with my shoelace
or playing with my hoodiestring.
And I'm like, please don't eatoff my plastic protector because
those are, you know, worth theirweight in gold.
(04:54):
Telomeres naturally shorten withage, which contributes to
cellular aging.
And telomere shortening actuallyoccurs faster in people with
major psychiatric disorders likeschizophrenia or bipolar
disorder.
Also, a little bit more abouttelomeres, they're highly
sensitive to environmentalinfluences, diet, and stress and
(05:19):
inflammation.
SPEAKER_01 (05:21):
So the idea that aging occurs more rapidly in
those with mental disorders isvery well understood.
But also the hypothesis was thatmoderate coffee intake could
slow those telomere shorteningsbecause coffee has some good
health effects as well.
So the data came from theNorwegian top thematically
(05:44):
organized psychosis study from2007 to 2018.
There was 436 adults, and 259had schizophrenia, 177 had
affective disorder.
That's like what you mentioned,like bipolar disorder, major
depressive disorder, andpsychosis.
The participants self-reportedtheir coffee consumption and
were grouped into zero a day,one to two, three to four, and
(06:07):
five or more.
And then additional informationcollected were things like
smoking habits and years smoked.
The participants drinking fivecups per day were generally
older.
And individuals withschizophrenia tended to drink
more coffee with those thanthose with affective disorders.
If you're interested aboutsmoking, 77% of them were
(06:29):
smokers, and their averagesmoking history was nine years.
And heavy coffee drinkers smokedsignificantly longer.
Smoking influences caffeinemetabolism, which can affect
results.
So they wanted to include thatin previous studies.
There's a lot of correlationbetween if you smoke, you have
way more coffee in your day.
SPEAKER_00 (06:47):
They looked at the telomere measures and how they
measured telomere length wasusing white blood cells from
blood samples.
And the results across thecoffee group actually formed a
J-shaped curve.
So the people who drank three tofour cups per day had the
longest telomeres, zero cups perday had the shorter telomeres,
(07:11):
and more than five cups a day,bye-bye benefit.
The benefit disappeared.
Interestingly, participants thatdrank four cups per day showed
telomere lengths equivalent tobeing five years biologically
younger.
And the associations actuallyremained after adjustments for
age, sex, ethnicity, whether youwere a smoker or not, the type
(07:34):
of mental disorder, and also thecurrent medications or
treatments that you were takingor that the person was taking.
SPEAKER_01 (07:41):
Some of the reasons coffee might have had this
protective effect was itcontains antioxidants and
anti-inflammatoryphytochemicals.
These phytochemicals may reduceoxidative stress.
Oxidation, of course, leads todamage and leads to the telomere
shortening.
Telomeres are highly vulnerableto both oxidative stress and the
(08:02):
inflammatory process.
So any way you can lessen those,your telomeres are not as
damaged.
So the authors of the studyproposed that moderate coffee
intake may help counteractfactors that accelerate aging in
psychiatric conditions.
And as you mentioned, Chris,there were some limitations to
the study.
So don't go out and startquaffing a bunch of coffee and
(08:23):
thinking you'll live forever.
SPEAKER_00 (08:25):
Absolutely.
So the observational design,again, cannot prove cause and
effect, but they were missingpretty detailed information.
What type of coffee was beingused or drunk?
Was it filtered, espresso?
Was it instant coffee?
Did the time of day of theconsumption make a difference?
You know what?
All coffee isn't necessarilycreated equal.
(08:47):
What was the exact caffeinelevels per cup?
But also you could be drinkingother caffeinated beverages.
There are some pretty highlycaffeinated beverages out there
on the market that may have hadeffect as well.
Results also could be influencedby lifestyle factors, medication
effects, and the interactionwith smoking.
SPEAKER_01 (09:09):
So coffee consumption worldwide is pretty
common, and studies seem to showit is beneficial in moderation.
So go coffee, but excess intakemay increase oxidative stress
and start to damage yourtelomeres.
So generally, the advice is tostay at four cups of coffee or
(09:29):
less.
SPEAKER_00 (09:31):
But really, the measurement is 400 milligrams of
caffeine per day, which you canget from other caffeinated
source sources.
SPEAKER_01 (09:39):
Now, they also didn't account for how much
creamer you put in your coffee.
SPEAKER_00 (09:44):
No, they didn't.
SPEAKER_01 (09:45):
I know somebody who doesn't drink black coffee.
SPEAKER_00 (09:48):
Interesting.
And the other thing I wasthinking about was diet, high in
processed foods.
That could be something that isharmful to the body, but that
isn't part of this study.
But it makes me think about whoyou are, what you eat, and drink
from your head to your feet.
SPEAKER_01 (10:03):
Coffee keeps me on my feet.
I'll tell you that.
I don't know where it's I don'tknow where I'd be without
coffee.
All right, that's science newsfor this week.
This week in Pat Science, we aregonna look at the house cats of
ancient China, because a newstudy came out that was really
interesting in cell genomics.
(10:24):
Early, early cats in China.
And we are going through earlylife cycle cat in our house.
That's Bricks.
SPEAKER_00 (10:33):
He's a kitten.
I've never had a kitten before,I don't think.
Like that I've been taken careof all by myself.
With you, of course, absolutelywith you.
But raising a kitten from akitten, it's been a lot and
quite a steep learning curve,that's for sure.
SPEAKER_01 (10:47):
Yeah, but it's got a steep learning learning curve,
and then it plateaus becauselike Bricks uses his litter box.
Like that is a huge dealcompared to a puppy.
And Bricks is like prettyindependent now.
Like, honestly, he can probablysurvive all around our house
where you would never leave apuppy that long young,
(11:11):
unsupervised randomly in yourhouse.
We still watch Bricks everybody,but like he can jump around and
he can get places and he cansleep places.
I don't think he's destructive.
Maybe some cats are, but not thesame way a puppy might eat
something and cause a problem.
SPEAKER_00 (11:27):
Like Bernoulli.
SPEAKER_01 (11:28):
Yeah, like Bernoulli.
We had to watch that guy like ahawk.
He ate everything.
He still does.
SPEAKER_00 (11:32):
And we still do.
He still does.
It's not I don't know.
Maybe by the time he's two,maybe that'll be the golden age.
SPEAKER_01 (11:40):
All right.
So in this study, house catsapparently arrived in China
around the 8th century AD.
But China was not cat-freebefore then.
There was a different speciesfilling the ecological niche.
New genetic evidence from thestudy reveals that leopard cats
lived alongside humans in China5,400 to 2,000 years ago, likely
(12:06):
helping with rodent control.
So that's the cool part.
It was not the domesticatedhouse cat.
What the heck are leopard cats?
SPEAKER_00 (12:16):
They're super cute.
They're small, and they'respotted wild cats that are
native to Asia.
And they likely began frequentlyancient human settlements to
hunt the rodents attracted tothe stored grain.
And so this relationship canresemble commensalism, where
animal where the animals wherethe cats benefited from humans
(12:41):
without being fullydomesticated.
Now, before you think that theywere cuddly, these early feline
visitors were probably notcuddly or tame like modern house
cats, but they exploited thesituation by living near humans
(13:02):
when it was advantageous tothem, but not seeking human
affection or to becomedomesticated.
So where there's humans, there'swaste or food and the rodents
like that as a food source.
SPEAKER_01 (13:19):
So these leopard cats just slunk about and ate
the mice that were around thehuman settlements?
SPEAKER_00 (13:27):
I'm not sure.
I wasn't living 5,400 years ago,but the study seems to link
human activity like that to theleopard cats hanging about.
SPEAKER_01 (13:36):
They'd be nice to look at.
How big are leopard cats?
Do you know?
SPEAKER_00 (13:45):
No.
SPEAKER_01 (13:46):
I just Googled that.
Are small, yeah, they are small.
They're like four to fifteenpounds.
So they're not any big yeah,they're small smaller than some
cats.
House cats.
That's crazy.
Okay.
Yeah, they're yeah, they gotlong legs.
They're roughly the size of acat, like a house cat.
Interesting.
(14:07):
Anyways, the house cats we knowof descended from the African
wildcat, not the leopard cat.
And that cat stuck around Africaand then went north to the
fertile crescent.
That's where it did really wellin the deserty areas there.
And there's been a long debateover when domestic cats got to
China.
In this study, they identifiedthat some remains in China dated
(14:30):
back to 730 AD, the TangDynasty.
Now, these cats probably werebrought by way of the Silk Road
along the trade routes.
The Chinese traders went westand saw some cute little kitties
and brought them back.
The genetic markers in alldomestic cat remains point to
Middle Eastern origins,consistent with those of the
(14:52):
spread of this domesticated catof that area.
SPEAKER_00 (14:56):
So the researchers analyzed mitochondrial DNA from
22 ancient cat remains, and thesamples range from 5,400 years
ago, the Neolithic age, to the20th century.
And what they found is that thepre-AD 200 remains contained
(15:20):
leopard cat MT DNA.
And after 730 AD, it was housecat MT DNA.
And so what that does is itsupports a species shift from
the leopard cat to the domesticcat over time.
And I'm super excited.
(15:40):
We've sent away Bricks' DNA tosee what kind of cat he is or
what region he is from.
SPEAKER_01 (15:48):
Yeah, they also use beyond the DNA, which is
interesting, the DNA from aroundthe Tang dynasty shows white fur
and short fur.
And art from that time matchesthis, which is cool.
So they used anthropology ofartifacts to match it to the
DNA.
And 85% of all the cats paintedduring that time had some white
(16:10):
fur.
So those paintings helpreconstruct what early Chinese
domestic cats looked like.
And any art before that time,like during the Han Dynasty, the
cats definitely look more likeleopard cats.
They're the art depicted aspotted cat with a long striped
tail and tall legs.
So these are like those earlyvillage cats that weren't really
(16:32):
pets but were hanging around.
I think that's cool.
They've cross-referenced thescience with anthropology, which
is itself a form of science.
SPEAKER_00 (16:40):
Mm-hmm.
That is really cool.
Because it I guess it paints abroader picture of history.
Leopard cats actuallydisappeared from human sites
around the third century AD, andthere was some possible reasons
for that.
It could have been because itwas a chaotic historical period,
lots of lots of welfare, aneconomic decline, and
(17:03):
fluctuations in population,which could have impacted the
changes in the available foodfor them.
Stability returned, and thedomestic cat had already arrived
and competed more successfullybecause they were more tame and
they were more compatible withliving directly alongside
(17:24):
humans.
One thing I love about Bricks isthat he comes in and he snuggles
and he's he likes humanaffection.
So yeah.
And so domestic cats eventuallyreplace the leopard cats in that
ecological role.
SPEAKER_01 (17:42):
So I guess as we close, interestingly, in this
study, it just shows what weknow.
Animals will adapt to humanenvironments when there's a
benefit to them, where thebenefit might outweigh some of
the dangers or the costs.
And you remember when we talkedto the hummingbird spy
scientist, there's hummingbirdsthat have evolved to live within
our human environments.
(18:02):
So that's cool too.
SPEAKER_00 (18:05):
I know, but I really want to see uh nest with the
tiny eggs.
And I he stu he studieshummingbirds, he hangs out with
hummingbirds all the time.
And when I said to him, Hey,have you ever seen a hummingbird
nest?
He said no.
And I thought, that'sinteresting.
SPEAKER_01 (18:22):
Yeah, they're just so tiny.
SPEAKER_00 (18:24):
They're just so tiny, you blink and you miss
them.
SPEAKER_01 (18:26):
Yeah.
But we're talking about cats,not hummingbirds.
SPEAKER_00 (18:29):
That's right.
And we don't want cats to eathummingbirds.
Here's a spoiler leave your catinside.
SPEAKER_01 (18:35):
Yeah.
Ginger's very cute, but she'sdefinitely more leopard cat than
a domestic cat because she's notas friendly as bricks.
No, that's not true.
She can be affectionate too.
SPEAKER_00 (18:45):
On her own terms.
SPEAKER_01 (18:46):
On her own terms.
All right, that's pet sciencefor this week.
That's it for this week's show.
Thanks for coming back weekafter week to listen to the
Science Podcast.
And a shout out to all the topdogs.
That's the top tier of ourPatreon community, The Popack.
You can sign up in our shownotes.
All right, Chris, let's hearthose names that are part of the
top dogs.
SPEAKER_00 (19:06):
Amelia Fete, Re Oda, Carol Hainel, Jennifer
Challenge, Linnea Janet, KarenCronister, Vicky Oteiro, Christy
Walker, Sarah Bram, Wendy,Diane, Mason and Lou, Helen
Chin, Elizabeth Bourgeois,Marianne McNally, Katherine
Jordan, Shelly Smith, LauraSteffenson, Tracy Leinbach, Anne
(19:29):
Uchida, Heather Burbach, Kelly,Tracy Halbert, Ben Rather,
Debbie Anderson, Sandy Brimer,Mary Rader, Bianca Hyde, Andrew
Lynn, Brenda Clark, BrianneHaas, Peggy McKeel, Holly Birch,
Kathy Zirker, Susan Wagner, andLiz Button.
SPEAKER_01 (19:48):
For science, empathy, and cuteness.
unknown (20:00):
Hopefully.
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