Better sleep and less heart arrhythmia in fruit flies when eating is restricted to 12 hours

[Rhonda]: There’s also the heart rate… [Satchin]: Yeah. [Rhonda]: Heart rhythm…. [Satchin]: Yes. [Rhonda]: …studies. So you mentioned earlier the chronic diseases. If you look at in the United States or industrialized
societies in general, the number one killer, people died in most of heart disease. [Satchin]: Yeah. [Rhonda]: Some sort of heart disease, you
know, and obviously, lots of different things regulate our susceptibility to heart disease. Metabolism, obesity. But you found some very interesting findings
doing time-restricted feeding in fruit flies. [Satchin]: Yeah. [Rhonda]: So can you talk a little bit about
that? I’m very interested in that. [Satchin]: Yeah. So fruit flies are used in science for many,
many years. And they’re, they have a short lifespan. They stay alive maybe 9 to 10 weeks max. So it helps us to figure out whether any intervention,
like time-restricted feeding, will have any positive or negative impact on health span
or healthy lifespan or longevity, etc. So what we did was, again, a very simple experiment. We took fruit flies and we gave them food
only for 12 hours during daytime, because fruit flies are diurnal animals, they fly
around during daytime, eat, and then at nighttime they sleep, or they had access to food for
24 hours, and we measured that they were eating the same amount of calories, and they were
also moving around the same distance. So, inside these bottles they could fly back
and forth. And at three weeks of age, their heart is
very healthy. It beats rhythmically. And although the fly heart is not like human
heart, they also have… [Rhonda]: Most people are probably shocked. Flies have a heart. [Satchin]: Yeah. So their heart is very similar genetic program. In fact, many of the genes that are now known
to be necessary for heart development in human were discovered in flies and vice-versa. There are many diseases in humans. Those are now put into flies to see what do
they do in the heart. So it was a very interesting model. Just like humans, the fly heart also becomes
weaker with age. So, by five weeks, the hearts don’t beat rhythmically. They have a little bit of arrhythmia, and
then they have the same dialysis. And so then the heart gets dilated with age. The beat-to-beat distance also becomes very
irregular. So what we found was when these flies eat
only for 12 hours, they don’t develop that arrhythmia as quickly as the normal flies
do, so they are protected from this heart disease. Then we said, “Okay, so if we introduce time-restricted
feeding later in the lifespan, then what happens?” Because one thing we could not do in mouse
study, because mice live for three to four years, we could not introduce time-restricted
feeding later in life. But in flies, when we introduce later in life,
they were also protected. The arrhythmia reduced in flies. And when we gave high-fat diet to flies, they
also produced arrhythmia and many heart conditions that we see in humans and those were also
protected in flies. And what is interesting in flies, we also
saw the flies sleep better when they eat only for 12 hours. So by five weeks, flies actually are just
like very old people. They have fragmented sleep at nighttime, and
they are sleepy during daytime, and that is completely prevented by time-restricted feeding. They have a good night sleep, they are very
active during daytime, the heart pumps nicely. [Rhonda]: Wow. Did you measure heart rate variability? [Satchin]: Yeah, so we did heart rate variability. So there are seven different parameters we
measured. [Rhonda]: And that improved? [Satchin]: Yeah, so all those seven parameters
improved to some extent. And when we introduced later in life, they
also improved. That was the surprise. [Rhonda]: Do know what or why? What’s… [Satchin]: Yeah, so what we found is, again,
one connection was back to mitochondria. What we found was the mitochondria were healthy,
or in the sense, they did not…they may not, maybe they were not producing as much of the
reactive oxygen species. [Rhonda]: The mitochondria in the cardiomyocyte,
in the heart cells? [Satchin]: Yeah, in the heart cells. [Rhonda]: Okay. [Satchin]: So we took the heart cells and
did gene expression for flies. We looked at all the genes, what we found
is a big cluster of genes whose expression actually reduced. And those are from the electron transport
chain. So that implied that maybe they have less
reactive oxygen species, or maybe reduced activity of ETC, electron transport chain,
is beneficial. So then to prove that, we actually knocked
down few components of ETC and those flies also have better heart. So that was one thing. [Rhonda]: Interesting. [Satchin]: Second thing that we found is proteostasis
of protein folding is necessary and in many other organisms people have shown that in
different components of protein folding machinery. But here, what we found is there is a new
protein folding, a very newly-identified folding machinery called ATP-dependent. It’s a chaperonin complex. Eight different components form this barrel-like
structure to fold proteins. And this requires energy, and that CCT component
has been shown to be important for various muscle, sorry, various cytoskeletal protein
folding, and it make sense for heart. And in fact, in humans there is a point mutation
in one of these ATP, sorry, CCT component that has been shown to predispose to some
heart disease. So it’s a beautiful story where found both
mitochondria and this protein folding machinery are necessary for this time-restricted feeding
beneficial, if beneficial effect. [Rhonda]: And this time-restricted feeding
was 12 hours? [Satchin]: No, it’s 12 hours because flies
are different from us. They don’t have thermoregulations, so when
they fast for a longer time, they cannot, they kind of can’t tolerate that. [Rhonda]: Oh yeah, they’ll, they’ll get cold.

2 Replies to “Better sleep and less heart arrhythmia in fruit flies when eating is restricted to 12 hours”

  1. Watch the full episode:

    FoundMyFitness episode page:

    More clips from this guest:

  2. Great video! Still didn't get what the CCT component has to do with time restricted eating or better heart health though.
    edit: I think I got it(?). Time restricted eating turns down genes that activate CCT production and CCT in humans is known to have a harmful mutation (likely in fruit flies too).

Leave a Reply

Your email address will not be published. Required fields are marked *