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.