Hey, can you drink seven cups of coffee
without feeling like you're going to have a heart attack? Or have you been called a lesser
human because you hate the way coffee makes you feel? You may think you have control over
your relationship with coffee, but it might just be… genetics! >> I drink about three cups every day,
I'd say. I think I could probably drink
20 cups without dying, 25.
>> Coffee makes me feel sane and
like a human. And the days that I don't drink coffee,
I feel like they're just going to be long and miserable, and they don't
really start until I've had coffee. >> How many cups of coffee
do you drink a day? >> I drink zero cups of coffee a day. Coffee makes me feel like
my insides are on fire, and that my blood is trying to escape
from my body through every pore. [LAUGH]
>> So I personally can't drink a whole cup of cold brew without feeling
like I'm going to die. I get this jittery feeling like my
heart's going to pop out of my chest. It may be different for you. I don't know your life, and
I'm not going to pretend like I do. But there's a reason why everybody
responds to caffeine in a different way.
The way your body metabolizes caffeine
is partly based on your genetics. A recent study by Dr. Marilyn Cornelis,
at Northwestern University, revealed that a variant in a specific
gene in your body is responsible for breaking down caffeine at different rates. >> My name is Marilyn Cornelis. I'm an assistant professor
at Northwestern University. >> Why is it that some people can
kind of drink a bunch of coffee and not feel anything, or
just feel a little bit of stuff. While others like me can't even
have one glass of cold brew, and we'll just freak out and
have a panic attack. >> There are a number of factors for why people might consume more
coffee than someone else. But much of the research now is showing
that it has a lot to do with the way you can metabolize caffeine. >> What does coffee metabolism mean? >> When we think about coffee, people
naturally equate coffee with caffeine. To make it simpler,
we talk about caffeine metabolism. But it further varies our ability
to break down caffeine into its metabolites that have less activity.
So they don't provide
those stimulant effects. If caffeine remains
unmetabolized in your body, you continually feel the stimulative
effects of caffeine. >> So are you saying that depending
on someone's genetic makeup, the more caffeine can stay in the body,
compared to other people? >> Yeah, genetics is one component. There are other factors too,
for example, smoking. Smoking actually increases your
ability to metabolize caffeine. So smokers tend to consume
more caffeine in order to get the same kick that other people,
or non-smokers. >> Wow. Why is that? >> Some of the key chemicals in
tobacco smoke induces the enzymes that metabolize caffeine. Their enzymes are acting more faster. >> Just more generally, what are the
beneficial effects that people feel, for people who enjoy coffee? >> Generally,
we think about the stimulant effects. People will say, I'm working all day. They might feel that they need to get a
bit of a kick in order to keep them awake, in order to remain stimulated,
and act efficiently.
Others just kind of feel good. Everyone kind of responds differently. >> What are some of the negative
effects that you have noticed for people who don't enjoy coffee, or
they can't drink a lot of coffee? >> The typical ones are the jitters,
anxiety, and those are kind of our obvious
responses to caffeine. And that kind of tells you to
just cut back on caffeine. >> Does that explain why some people just
love that kind of stimulant activity, while some people just really don't
like it, they don't respond well to it? >> Actually,
I did a couple of studies in this area, one where we looked at
coffee consumption behavior. And in a different study we looked at the
caffeine metabolite levels of the blood. And what we found is that
those people with the genetic variance that results in
increased coffee consumption, they also had lower levels
of caffeine in their blood. Which shows you again that
they're metabolizing caffeine so quickly that they need to consume more
in order to get that caffeine fix. >> What are the genes
that you've identified? >> The key one is cytochrome P450 1A2.
CYP1A2 is the short version of it, they refer to it as the xenobiotic
metabolizing enzyme. It's responsible for
95% of caffeine metabolism. >> Everyone has this gene, correct? >> Everyone has a gene, but there
are different variants within the gene. And that's where we find these individual,
between person differences, in the CYP1A2 activity. >> So, if it's true that genetics,
for some parts, play a role in coffee consumption, will I always be
a person that can't drink coffee? Or can I kind of condition myself,
or how does that work? >> That's a great question. You're discussing what
we call a tolerance. I guess you would have to at least
get past your first cup of coffee.
And, if it's the jitters that
are bothering you, I guess you can try to kind of train yourself or
condition yourself, like you say. That would probably take a while. And I think in most cases,
because you just don't like it, you just won't even try. But then, there are some people where
they don't like coffee, not at all, because of the genetic, or
their response to caffeine. They don't like the taste. And there are also genetics for
taste, as well. For example, for me,
I really like the effects of caffeine. I can get caffeine from other sources,
colas and other things. >> If it is genetics, can I pass it down? Is it heritable? >> Yes, it is. Obviously you would get part of the genes
from your mother and your father.
And if they're both heavy coffee drinkers
or are rapid caffeine metabolizers, then it's highly likely that you
will be a rapid metabolizer as well. >> Wow, so just blame your parents. [LAUGH] Thank you so much for
speaking with me, that was great. Like most of our other
bodily characteristics, genetics plays a huge role in
influencing our caffeine intake. Typical. But hey, at least it's not your fault you can't
pound coffee like you're a Gilmore girl. >> How many cups have
you had this morning? >> None. >> Plus? >> Five, but yours is better. >> There are people that can guzzle
an entire can of Maxwell, just like there are people who can survive a college
kegger without a vicious hangover.
It's just their biology. Also, people hate coffee for a plethora
of reasons like taste and smell, and that's biology too. Zamn, the body won't give us a dang break. It's also very interesting to find
that coffee metabolism is heritable. So just like every other issue in
your life, blame your parents. It works every time..
