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Inflammation | Miscellaneous | Heatlh & Medicine | Khan Academy

December 29, 2019

with Dr. David Agus, who is a professor of engineering
and medicine at USC. DAVID AGUS: Um-huh. SALMAN KHAN: And we’re
looking at pictures here of things that seem
very different to me. What is the
commonality right here? DAVID AGUS: The commonality
is inflammation. So inflammation can be manifest
by a runny nose in a cold or getting the flu. It could be manifest by
an infection in your toes. It could be hitting your
head playing football or hitting your arm when
you fall playing a sport. All of those can
cause inflammation. SALMAN KHAN:
Because inflammation has a certain meaning
in everyday language. At least when I
imagine it, it means something that’s
swollen and red. But here, we’re talking
about inflammation in more of the medical
or the scientific sense. Things are swollen and red
because of inflammation. DAVID AGUS: Right. SALMAN KHAN: And so
what is inflammation? It isn’t just
swollen and redness. I mean, the football player
isn’t getting swollen and red, or is he? DAVID AGUS: So inflammation is
when your body senses danger. So when something
is wrong, whether it be an infection, whether it be
trauma in the case of football players, whether it be
a cold, your body senses danger and sends in
its frontline soldiers, which are the immune
cells, in order to fight whatever’s causing it. So if it’s trauma, the
immune cells go in there and they help rebuild the
tissue that’s damaged. If it’s a bacteria,
they go in there and they try to take
away the bacteria so you can get over
that cold or that flu. And so that whole process
we call inflammation. SALMAN KHAN: I see. DAVID AGUS: It’s
a danger process. SALMAN KHAN: So it’s
the immune cells going to the sign of danger to
either fight the danger itself or repair the aftermath– DAVID AGUS: Yup. SALMAN KHAN: –of the danger. So that sounds
like a good thing. DAVID AGUS: It’s
an awesome thing. The problem is, your
body, all of us, we care about what happens
today, not down the road. SALMAN KHAN: Right. DAVID AGUS: And this
is one of the take home points that astonished me
when I start to think about it, is that nature,
evolution, selects out, for who has good kids. And that’s what
evolution is about. It’s about having children. We call progeny. SALMAN KHAN: Right DAVID AGUS: It’s not
about what happens when you’re 80 years
old or 90 years old. And so inflammation is
fantastic about dealing with today’s ramifications. The problem is if you
get the flu today, your risk of cancer and
heart disease a decade or two decades from now are up. SALMAN KHAN: If I
get the flu once? DAVID AGUS: If you
get the flu once. SALMAN KHAN: Really. DAVID AGUS: So those
five, six days– SALMAN KHAN: You’re worrying me. DAVID AGUS: –when
you feel horrible, your inflammation
is through the roof. That’s having ramifications
down the road. SALMAN KHAN: Right. I mean this is already
getting a little scary for me because I’ve had the flu. So I already feel a little
worried about my cancer risk. DAVID AGUS: I can tell
by looking at you. [LAUGHTER] SALMAN KHAN: You can
tell by looking at– [LAUGHTER] And the symptoms that we get
when we have the flu or a cold, these are actually– it’s not
the virus that’s– the virus is causing the inflammation,
which is causing the symptoms. DAVID AGUS: Yeah. And that’s what’s wild. Is that when you get a virus,
your immune system attacks it and you get a fever. I still don’t know
why we get fevers. It’s one of those things
where the– we call them the cytokines, which are
proteins the immune cells make to send out and get
more reinforcements and tell the body what to do. It causes a fever. Is a fever good? Is a fever bad? I don’t know. We take Tylenol
to lower a fever, but is that a good thing? Nobody really has looked at
the long-term ramifications. They look at short term. But how does it affect
a decade from now what’s going to happen? We just don’t know. SALMAN KHAN: Wow. Wow. And what you’re saying
is that the reason why we have inflammation
is, yeah, something has happened to my body. I have some trauma, some injury. And you were saying
this to me earlier, you might have to run
away from a lion tomorrow. So fix Sal or fix
David up right now, so that he can run away
from the lion tomorrow. But in the wild, I might
only live to 40 anyway. So why even worry about whether
that person might get cancer if they get to 40
or 50, once they’re past the age of reproduction. DAVID AGUS: Eactly. The body has to
choose priorities. And the priority clearly is
today rather than tomorrow. And so an amazing study
was done in that we gave patients what
we call a statin. So statins were
drugs– S-T-A-T-I-N. They were drugs that were
developed because they blocked the synthesis of cholesterol. SALMAN KHAN: Right. DAVID AGUS: And
we thought people with higher cholesterol,
particularly the bad one called LDL, those people have a higher
incidence of heart disease. So if we block the
synthesis, we’re going to affect heart disease. And what do you know, we did. A dramatic effect, we lowered
the death from heart disease with these drugs. SALMAN KHAN: Right. So it seems like they worked. DAVID AGUS: They worked. Then a company, or
a very clever group, did a trial where
they gave people with normal cholesterol
these drugs. And they had a dramatic effect
in that it delayed heart attack and stroke by almost
a dozen years. SALMAN KHAN: Wow. DAVID AGUS: And it reduced
the incidence of cancer by about 40%. SALMAN KHAN: So
cancer, something– I mean we don’t
associate cholesterol– DAVID AGUS: Totally different. SALMAN KHAN: Wow. DAVID AGUS: So it turns
out these drugs, which were the biggest drug in
terms of sales we’ve ever had, worked by lowering inflammation. So their effect in heart disease
wasn’t by lowering cholesterol. It was predominantly by
lowering inflammation. SALMAN KHAN: Right. Right. DAVID AGUS: And the
effect on cancer was by lowering inflammation. In fact, do you remember
when the swine flu came out a couple years ago? SALMAN KHAN: Right. Right. DAVID AGUS: So if you
got the swine flu, the only thing that
protected you from your lungs collapsing and going on
what we call a ventilator, a breathing machine, was
being on one of these statins. SALMAN KHAN: Because it
would stop the inflammation. Because the swine flu
people were dying from is the inflammation going nuts. DAVID AGUS: Yeah. SALMAN KHAN: This
is fascinating. So the people who are
dying of heart disease, is it necessarily
the cholesterol that’s killing them? Or is the inflammation
that’s causing cholesterol? DAVID AGUS: Well, I think
it’s this chicken and the egg phenomenon. That’s it. The inflammation allows
cholesterol to deposit– SALMAN KHAN: I see. DAVID AGUS: –and they together. SALMAN KHAN: I see. I see. So it’s really the statin
affects inflammation, which then reduces cancer by
stopping the inflammation and stopping the– DAVID AGUS: Exactly. SALMAN KHAN: –cholesterol. DAVID AGUS: One of those
problems we have a biology, in medicine, it’s
what you can measure. And so I can
measure cholesterol. SALMAN KHAN: Right. DAVID AGUS: I don’t
really know how to measure inflammation well. So while we can make these
association in big studies when we look back, if I had a
metric, if I had a blood test or something to look
at for inflammation, I can optimize things. SALMAN KHAN: Can you not measure
just the amount of cytokines and other inflammatory
type of things that become increased in
your– does it happen? DAVID AGUS: You’re right. But are different
types of inflammation. So some inflammation can
be good, some can be bad. Some can be really causal. Some could be a
little bit causal. And so we’re putting
them all into one basket now, which is inflammation. The key is to
start to tease them out and be able
to modulate them. You can develop a drug. But then you have to optimize
it for a particular purpose. SALMAN KHAN: Right. Right. DAVID AGUS: So these were
optimized to lower cholesterol. And they do that very well. They also lower inflammation
and they work beautifully in that regard. But how do we optimize
that going forward? What it also means
is that when you look at your lifestyle
and my lifestyle, we have to limit inflammation. So what are the easy
ways to do that? One is, which I think
should be mandatory things, like the flu shot. SALMAN KHAN: Right. DAVID AGUS: So
again, the flu shot will certainly delay you
from having or prevent from having bad flu. SALMAN KHAN: That’s good today
and good today and tomorrow. DAVID AGUS: And tomorrow– SALMAN KHAN: Yeah,
yeah, yeah, yeah. DAVID AGUS: –because it
limits heart disease and cancer down the road. That SALMAN KHAN: I had no clue
that the flu– I thought it was just a nice thing,
avoid a week of sneezing, and you know. But the flu shot, you can
actually reduce your cancer– DAVID AGUS: And heart
disease down the road. And we have to think
long term as a society. SALMAN KHAN: What about statins? I mean it seems like– these are
drugs like Lipitor and Crestor. I mean would you– I mean no one
should take our medical advice based on a thing in video. DAVID AGUS: Right. SALMAN KHAN: I mean are
people taking it just for heart disease or are people
taking it more broadly now? DAVID AGUS: Listen. I mean I’m a believer
that these drugs have such a profound
effect on cancer, heart disease, stroke,
potentially Alzheimer’s, that you should consider taking
it to prevent these diseases. And again, we’re giving
no recommendations. But what I say is
you, your parents, they should talk about
it with their doctor. And so why shouldn’t
I be on this drug? SALMAN KHAN: Right. And there are some side effects. But they’re easy to test for. DAVID AGUS: Test for, and
then they’re reversible. SALMAN KHAN: Right. OK. So you’re not going too– DAVID AGUS: So
with anything, you got to do a risk and a benefit. SALMAN KHAN: Right. DAVID AGUS: And you
have to look at you and say am I high
risk for X, Y, and Z? If you are, what can
prevent or delay it? The name of the game is
not treating disease, it’s preventing disease. SALMAN KHAN: Right. Right. Now, this is fascinating. Well, I might talk to
my wife about getting some– well, no advice here. Everyone should talk
to their doctor. DAVID AGUS: By the way,
another great medicine to reduce inflammation
is called aspirin. SALMAN KHAN: Aspirin,
I’ve heard of that. DAVID AGUS: Yeah. It’s a hell of a drug. Again, there are side
effects to aspirin. It can affect bleeding. But at the same time,
it’s a dramatic effect by lowering inflammation. SALMAN KHAN: Right. And that is its
main side effect. I mean it’s this age-old drug. It’s a blood thinner. So if you get a cut or you bleed
while you’re taking aspirin, you might bleed more. DAVID AGUS: Right. Blood thinner is a funny term. I’m not quite sure
what it means. I keep taking paint
thinner when you see it. SALMAN KHAN: Right. That’s kind of how I imagine it. DAVID AGUS: It binds
to the platelets and blocks them from activating. It stops them from
working really well. SALMAN KHAN: So it’s
more anticlotting. DAVID AGUS: Right. And platelets are one of the
key components of clotting. And they certainly affect it. SALMAN KHAN: Right. So your blood will have
the same viscosity. It just won’t clot as easily. DAVID AGUS: Exactly. And you could certainly
paint a wall with either one. SALMAN KHAN: That’s
a little morbid. All right. Well, thanks a bunch.


  • Reply oDDmahnsta October 4, 2011 at 12:34 am

    more graphics = more views and easier to understand

  • Reply Teh Lian Kiat October 4, 2011 at 12:48 am

    why not take fish oils? it helps with inflammation. right?

  • Reply John Horton October 4, 2011 at 12:50 am

    Inflammation does not mean cancer!

  • Reply superdau October 4, 2011 at 1:18 am

    Wow, an antivaccer and know-it-all. Could you please leave the internet? It's not for you! It was developed through the same methods that gave us medicine. So if you distrust sience, lock yourself in a cave a see how old you get.

  • Reply xponen_ October 4, 2011 at 2:20 am

    @lastchancemst1 fever increase body temperature and help immune system to work, but it can't kill virus. The hi temperature makes body less favourable to fungus, and also help enzyme to work quicker, but it won't kill virus. Virus can survive hundred degree Celcius and still didn't die, but it can die simply from sunlight and oxygen.

  • Reply superdau October 4, 2011 at 2:23 am

    How does it feel to live paranoid in fear all the time? I'm sure you never looked at scientific studies yourself, but just spout what someone else fed you on the internet. Don't you notice you're just used?
    (btw. you should end your distrust for correct spelling)

  • Reply teargardens October 4, 2011 at 3:01 am

    Do Not get a vaccine, unless you like to help the M.I.A.C. kill you faster. Go ahead,ingest the GMO, fluoride & drug filled manciple water, its good for you like D.U. munitions & radiation!

  • Reply SalsaTiger83 October 4, 2011 at 8:21 am

    @teargardens funny enough, children of parents with this view are much more likely to die…. So if you don't like your children, go ahead and let them suffer, be crippled and die from diseases the rest of the developed (and most of the undeveloped) world doesn't even know any more…

  • Reply Kuro's game channel October 4, 2011 at 8:42 am

    I'm really loving these curiosity videos. Keep going Khan.

  • Reply superdau October 4, 2011 at 12:43 pm

    This video really seems to have brought out the conspiracy crowd. Guys, accepting every non-mainstream opinion you find somewhere does not make you a sceptic (which would be a good thing), but an idiot. You really think you know more than people, who did research in their fields for decades?

  • Reply teargardens October 8, 2011 at 3:03 am

    @axblake1 If only I was, I wish it wasn't as bad as it is really. The vaccine deception is just one of an endless list of epic disgusting TRUTHS that most are uncomfortable with, like yourself. Their is mountains of scientific NON BIG PHARMA FUNDED independent evidence, that proves what I say is FACT and truthful. Do you even know about mind,weather and matter control super technology? No, of course not your plugged into the matrix, a willing complacently ignorant zombie. Go back to sleep.

  • Reply teargardens October 8, 2011 at 3:23 am

    @axblake1 I found out in the latter part of reverse engineering all of our common history in regards to suppressed super tech., ancient tech. and civilizations, micro/macro economics global and local,elite bloodlines & pretty much all things esoteric & occult. I went into it all trying to disprove weather control. Unfortunately, not only could I not disprove it, to my dread I came across mind control and an open conspiracy to not only form a world government but to carry out global genocide.

  • Reply teargardens October 8, 2011 at 3:26 am

    @axblake1 If only it just stopped at weather and mind control and global genocide. So, as you could probably guess, their are much bigger fish to intellectually fry than the obvious poisoning of the masses. It to late anyways, we are on stand by for the next false flag/man made event. I wish I cared to have the time to lead you by the hand. But you may still be able to find it on your own, before they internet kill switch it all away, good luck comrade, your going to need it. FEMA zone 10 out.

  • Reply Bob Hamilton October 10, 2011 at 2:23 am


  • Reply madengineer October 19, 2011 at 8:57 am

    Why does this video sound like one of those google adverts spamming medicine?

  • Reply Frank Patrick November 2, 2011 at 12:17 pm

    funny enough. i know more people that got the flu after they got the flu shot then those that didn't.

  • Reply Zachary Smith December 12, 2011 at 2:02 am

    @evilmindedsquirrel Many people do get relatively minor infections from the flu shot, but it is nothing compared to a full-strength flu infection. However, I agree with your implication that flu shots might be more harmful than good for some people–one reason I do not believe that they should be madated, as Dr. Agus suggests. I personally do not get flu shots, to avoid the inflammatory response I get from them.

  • Reply SB9101 December 16, 2011 at 6:32 pm

    sleep is good to prevent sickness

  • Reply MultiCheeseGrater April 16, 2012 at 11:52 pm

    how does this guy not know what causes a flew, jesus christ.

  • Reply MultiCheeseGrater April 16, 2012 at 11:52 pm


  • Reply William Tseng April 23, 2012 at 8:13 am

    My AP Biology teacher says that the reason we get fevers is because it is our body's attempt at creating a system that is unsuitable for the bacteria/virus and hopefully killing them off. Can anyone confirm?

  • Reply adilshussain May 23, 2012 at 8:40 pm

    "I still don't know why we get fevers"
    Are you serious?! The whole point of a fever is to increase the internal temperature of your body in order to kill the invading bacteria that cannot live at higher temperatures.

    I'm not sure about this professor, he reminds me a lot of Rick James (8:23 "aspirin is a helluva drug..")

  • Reply Mario Ortega May 29, 2012 at 9:48 pm

    @Willthabeest I'm not confirming but that's what my biology teacher told me too. She also told me that that since your temperature is raised a lot then your proteins get denatured. I think it's true too cause proteins get denatured if too hot or cold.

  • Reply David Johnson August 1, 2012 at 5:08 am

    Need to discuss dietary sources of statistics such as oyster mushrooms. P is treating. Need several programs on inflammation regarding arthritis, especially due to gastric problems like c diff, staph and the role mast cells play. Your wife should be an excellent resource. Pay close attention to the role of acetaldehyde in triggering mast cell degranulation. Pay attention to the fact that bi organisms can process ethanol to acetaldehyde, where normally enzymes complete the metabolism, the organis

  • Reply David Johnson August 1, 2012 at 5:14 am

    Correction Statins not Statistics, P Ostreatus

  • Reply MrManimal88 January 7, 2013 at 4:26 pm

    We know that fever prohibits the replication of some viruses and bacteria. In that sense it is beneficial. Another physiological take on fever is that the elevated temperature causes hemoglobin to release its oxygen more readily to peripheral tissue… again, this is beneficial, because the process of killing microbes involves the use of oxygen to produce reactive oxygen species (NADPH oxidase) like superoxides, hydrogen peroxide and hydroxyl radicals, oh, and BLEACH.

  • Reply deathmetalchar February 7, 2013 at 4:26 am

    lol my pharmacy teacher told us to watch these videos

  • Reply sleepyhead7391 March 19, 2013 at 8:45 pm

    mine said the same thing, but think what Dr Agus meant was that he doesn't know the exact mechanism that causes a fever

  • Reply Suneel Rana August 12, 2013 at 9:19 pm

    Hey, thank you for these videos…. Can you do a vid on mandatory vaccinations. There's plenty of controversy on this subject and would like to hear your perceptive on it. Thanks

  • Reply DirtyDwarf January 4, 2014 at 10:07 pm

    1:15 well apart from the fact that cold and flu are viruses >_>

  • Reply theWellSeasonedWoman January 19, 2014 at 12:22 am

    what a load of pharma propaganda regarding statin drugs – no mention of how many have been killed or permanently disabled by the way these drugs interfere with the body's natural processes;  your brain is cholesterol, every cell wall is cholesterol, your hormones are based on cholesterol.  You get better effects via ingesting turmeric in your food.  and no, some of the side effects of statins are NOT reversible.

  • Reply Michael Ockerby May 5, 2014 at 5:37 am

    Don't have a wide spectrum diet; just take statins. all gee homee   

  • Reply Fl Lf July 14, 2014 at 7:26 pm

    Thanks for the info! There are many natural, cheap remedies for inflammation.

  • Reply MistakenMystery August 21, 2014 at 4:01 am

    Propaganda on the Flue shot is heavy in the end of this video. Fuck the Flu shot, Ain't nobody got time fo that!

  • Reply Sy October 28, 2014 at 7:37 pm

    right….right….right lol

  • Reply Annika Javette October 8, 2016 at 10:25 am

    Loved your videos in the past but this is horrific 🙁

  • Reply Johnny Ni November 10, 2016 at 4:14 am

    khan academny is great for you!!

  • Reply ben amiri June 4, 2017 at 10:18 am

    the best channel it's better then my school

  • Reply Kahar Shital November 7, 2019 at 1:52 pm

    I love this video

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