Society’s Sweet Tooth… the Brain’s Response to Sugar | Amanda Maracle | TEDxQueensU

Society’s Sweet Tooth… the Brain’s Response to Sugar | Amanda Maracle | TEDxQueensU

August 21, 2019 50 By Stanley Isaacs


Translator: Mirjana Čutura
Reviewer: Rhonda Jacobs I’d like to start off
by telling you a story. It’s about a woman named Barbara. Now, unfortunately for Barbara, when she was young, unhealthy habits were modeled at home. And several of her close relatives struggled with a very specific
type of disorder. As Barbara got older, she realized that exposure
to a certain type of substance was highly rewarding for her, and she began actively seeking it out and consuming it without experiencing,
really, any negative consequences. Over time though, Barbara began to experience
the negative health effects associated with taking this substance
for a long period of time. She had intense cravings. She began to struggle with depression. And even though she had tried
to reduce her intake several times, she had been unsuccessful each time. Now, I’m sure you all have an idea of what
it is that Barbara is struggling with, and if you had guessed addiction,
then you would be correct. Barbara’s not alone in this. One in five Canadians will meet
the criteria for substance use disorder at some point in their lifetime. I want you to think about this. I want you to look to the two people
on your right-hand side and then the two people
on your left-hand side. Statistically speaking, this means that one of you will meet
the criteria for substance use disorder at some point in your lifetime. Four in 10 Canadians will meet the criteria for addiction
to tobacco products. Two in 10 Canadians will meet
the criteria for addiction to alcohol. And six in 100, about six percent
of the population, will meet the criteria for addiction
to cannabis and other illicit substances. The social cost of this,
according to a 2006 study, was approximately
39.8 billion dollars each year. This means that it costs
just over 1,200 dollars to every man, woman, and child in Canada. And this includes both direct costs, like the cost of healthcare
and law enforcement, and indirect costs,
like lost productivity at work. Now, Barbara’s specific addiction will cost Canadians approximately
4.5 billion dollars each year. Now, some of you may have an idea of what
the substance Barbara is addicted to is. Some of you might be guessing “tobacco,” some of you might be thinking “alcohol,” some of you might be thinking something
a little harder, like cocaine or heroin. In actuality, Barbara isn’t addicted
to any of these substances. Barbara is addicted to food. Now, some of you might be surprised
by that statement, and some of you may disagree
with that statement. And in fact, the controversy
surrounding food addiction has been waging for the better part
of the last 10 years on two fronts. The first is what I like to call
the social media war. On one side, you have individuals
that claim to suffer from food addiction and provide anecdotal evidence
of their own experiences and the experiences
of the people that they know. And on the other side is – you have individuals that claim
that the words “food addiction” are simply a cover, an excuse
for developing obesity or for having low self-control. The other front on which this controversy
is waged is in the scientific one. Ten years ago, health scientists started saying,
“Look, we’ve got people coming to us, and they are showing
hallmark features of addiction: They are showing tolerance. They’re showing withdrawal. They’re showing impulse-control issues.” And on the other side, you had individuals that studied
the sort of classic drugs of abuse, like cocaine and like heroin, who said that food could not be classified
in the same way as those drugs and that the neurobiological things
that happen when someone becomes addicted aren’t present in individuals
that claim to suffer from food addiction. Now, this is where I came in. This is when I began
to be interested in research, and I had been exposed
to this controversy in social media, and I’d been exposed to it
in the scientific field, and I was really interested. So when I started my research,
I started with a very simple question. And that question was, “Can the rewarding properties
of food produce addiction?” Now, one of the hallmark features
of addiction is compulsion. And if you look up the definition
of “compulsion” in the dictionary, it is “the irresistible urge to behave in a way that runs contrary
to your express, conscious wishes.” In addiction, we see
this present as individuals that are unable to stop themselves
from consuming a substance even if they no longer wish to and even if they no longer derive
any enjoyment from doing so. So I went back to my original question, “Can the rewarding properties of food
produce addiction?” and I modified it to, “Can the rewarding properties of food
produce compulsion, this hallmark feature of addiction?” Now, to do this, I used
an already-established model, and I exposed animals –
rats, specifically – to a substance that is commonly found in food
and also happens to be highly rewarding. And that substance is refined white sugar. And I exposed these animals
to a concentration that is commonly found
in sweetened beverages. So I used a 10 percent concentration, and for comparison, the average can of pop
has about 11 percent. And I exposed these animals
to this concentration of sugar for 12 hours a day, every day
for about a month. And some very interesting things happened. The first is that they began to binge. They were consuming about five percent
of their body weight in the first hour every time
they had access to the sugar. Now, for comparison, you can think of someone
my size and my body weight drinking about three liters of pop or eating one-third of a kilo
of sugar in one hour. They also heavily escalated
their intake over time. By the end, in a 12-hour period, they were consuming roughly one-fifth
of their body weight, which, again, for comparison, is someone like me
consuming 13 liters of pop or 1.3 kilos of refined white sugar. Imagine … drinking this or eating this every day. So this is really shocking to me. But what I was interested in was whether exposure to this amount
of sugar could produce compulsion. Now, unfortunately,
you can’t ask an animal, “Are you addicted to something?” You can’t ask an animal,
“Are you compulsive?” So I had to put them
in an evolutionarily relevant situation, one that pit their instinctual
mechanism for avoiding danger versus this learned behavior
to seek out and consume sugar. And when I did that, the animals that had been consuming
massive amounts of sugar completely ignored – they completely overrode this instinctual
mechanism in favor of seeking out sugar. And this is something that normal,
healthy animals will not do. But what was happening neurobiologically? What was happening in their brains? Well, there’s some very specific changes
that happen to a brain when it becomes addicted to a substance, and the changes that happen are different depending on the type of the brain area
that you’re looking at. The specific area that I was interested is implicated in survival-based
motivated behaviors. And it happens to sit
between two other brain areas that have already been heavily implicated
in the development of addiction. The first in the amygdala, which processes
emotional and rewarding information, and the other is the striatum, which is responsible
for reinforcement-based learning and motor control. Now, this area had actually already
been looked at by a colleague of mine, and he was looking at it in animals
that self-administered cocaine, classic drug of abuse,
over a long period of time. And he was able to show
that there’s a very unique change that happens to the neurons
in this brain area. They respond very differently to dopamine, which is the brain’s primary
rewarding neurotransmitter, than the neurons do
in the brains of animals that had either had no exposure to cocaine or had been exposed to cocaine but weren’t self-administering it
for a long period of time. Now, when I looked at
this brain area in my animals, to my astonishment, I found
exactly the same change in their brains as what was happening in animals
that were self-administering cocaine. So, what’s happening? What does this mean? Well, our brains are highly
evolved, adapted organs. And our brains have evolved
to seek out rewarding substances and perform rewarding behaviors because in our evolutionary history,
that meant survival: things like having sex,
eating good food, avoiding danger. Unfortunately, this highly adapted system, when it’s exposed to unnaturally
reinforcing substances like drugs – this formerly adaptive process
becomes maladaptive. There’s this war going on
between our evolved biology, that pushes us to consume
rewarding substances and pushes us to perform
rewarding behaviors, versus our modern environment, a society in which unnaturally reinforcing
substances are plentifully available. This is why we are starting to see
addictions to things that are fundamentally new
to our modern society: addictions to things like gambling,
to video games, and to food. Now, there’s still
quite a bit of controversy in the scientific literature about what exactly
the properties of food are that can produce addiction. But I think, in general, as a society, we need to start thinking
about addiction beyond drugs. We need to stop having such a rigid idea of what the substances are
that can produce addiction. We need to stop thinking
about it as drugs versus other. Because, really, any highly rewarding
substance or behavior can produce the same behavioral
and neurological things that we see in addiction. We need to start thinking of addiction as a very-old brain’s way of trying
to deal with a very new problem. So I want you to do something for me
when you leave here today. I want you to just be aware. And when you see hotly-debated
topics like this one in social media and other spheres, I want you to think, and I want you to question, and I want you to investigate because, as I found out, addiction doesn’t necessarily look like
what it used to any more. Thank you. (Applause)