Part 1 哈佛公开课 Food for Thought

Food for Thought: The Relationship Between Food, Gut and Brain

Hello, I am Alessandro Cicerale, a Research Fellow at the University of Torino. On behalf of the whole team, I would like to welcome you to the second edition of "Food for Thought." In this course, we will explore how the food we eat affects our body and our brain. We will also delve into the influence of our emotions and thoughts on our food intake.

By the end of this course, we hope you will be able to answer these questions. Our journey will begin by understanding how the brain works and conclude with exploring the relationship between the gut, microbiome, and the brain.

In the first week, we will focus on the brain. We will discuss its structure, its relationship with other organs, and reasons why the food we eat could impact it. In the following weeks, we will introduce various subjects.

We will start with the reward systems and food addiction and then move on to psychological topics such as orthorexia nervosa （An Obsession With Healthy Eating）, emotional eating, and the role of our experiences in our food choices. The later weeks we'll take a more biological approach. In the fourth week, we will explore the effects of unbalanced diets on the brain and mood.

We will also discuss the impact of both beneficial and harmful molecules present in our diets. Finally, the fifth and last week will be dedicated to exploring the intricate relationship between our gut, brain, and the microbiome.

Each week of the course will offer different types of content, including articles, quizzes, and videos. Additionally, we will provide reflection ideas to help you grasp the two-way relationship between our brain and the food we eat.

So, let's dive into the question: How does the food we eat affect our mind, brain, and body? Join us on this enlightening journey, and together we will discover the answers!

What topics will this course cover?

During this five-week course, we’ll discuss biological and psychological topics related to eating and food.

During the second activity of the first week, we’ll explore some background notions related to the rest of the course. We’ll talk about the brain and its metabolism, as well as the axes that link the brain with our gut and other organs.

The first activity of the second week will be devoted to how the brain responds to feeding, focusing on the reward systems. The videos and articles will introduce you to the subject of the second activity of that week, food addiction.

Going forward, in the third week we’ll discuss the relationship between the mind and food, touching on topics such as emotional eating and restrained eating. Emotional eating, and a way to measure it, will also be explored.

In the fourth week, we will transition from psychological topics to biological topics. In the first activity, we will discuss eating disorders, and in the second activity, we’ll focus on the effects on the body that unhealthy eating behavior can have.

In the fifth and final week we’ll continue our discussion of biological aspects, focusing on the gut-brain axis and the role of the microbiome.

The last week now also includes a review of the studies that investigated how modifying our microbiome can affect our health, as well as a final test.

A note on course moderation

The Educators will not be able to join the discussions themselves or respond to individual comments, but the course encourages a strong learning community. The learning is focused on debate and discussion – supporting other learners, sharing your own experience and knowledge, and listening to new perspectives.

What do you know about the brain and food?

Before jumping into the course content, we’d like you to pause for a few minutes and reflect on what you know now about the relationship between food, psychology, and the brain.

The following questions will help you focus on some aspects of this relationship, and give you a better idea of what you can expect to learn in this course.

Begin Quiz :P

Question 1

Food can affect our mind only after we eat it.

True

False

Question 2

Good “brain foods” or supplements will make you smarter, quickly.

False

True

Question 3

Serotonin sirəˈtōnən （血清素）is a molecule linked to mood levels. Therefore, eating foods rich in serotonin could…

Improve our mood

Decrease our mood

Have no effect

Question 4

Food addiction and eating disorders are the same thing.

False

True

Question 5

The gut produces molecules that can increase or decrease our appetite.

Yes

No

Answers

Question 1

Food can affect our mind only after we eat it.

False: Food and eating can influence our minds in multiple ways, and some of them start indeed before we even take the first bite of food! Looking forward to going to eat a favorite dish for dinner, or the mouth-watering effect of smelling some nice food are two ‘good’ examples.

Question 2

Good “brain foods” or supplements will make you smarter, quickly.

False: Many studies investigating the relationship between food and cognition use interventions that last from weeks to months. Short-term effects are sometimes investigated, but in general, the results are less clear.

Question 3

Serotonin is a molecule linked to mood levels. Therefore, eating foods rich in serotonin could…

Have no effect: There are very few foods that contain serotonin! Any serotonin found in the bloodstream cannot reach the brain due to the blood-brain barrier, which we will discuss in the first week of the course.

Question 4

Food addiction and eating disorders are the same thing.

False： Food addiction is an interesting but controversial topic. While there are many studies supporting it, any addictive property of food would not be responsible for many eating disorders, such as orthorexia nervosa (an obsession with healthy eating with associated restrictive behaviors) or anorexia nervosa  (often simply called anorexia — is an eating disorder characterized by abnormally low body weight, an intense fear of gaining weight and a distorted perception of weight).

Question 5

The gut produces molecules that can increase or decrease our appetite.

Yes： The gut-brain axis includes hormonal communication pathways, and they include hormones, such as ghrelin. Ghrelin that is secreted by the stomach when it is empty, increases hunger. Another substance, peptide YY, is released after meals, and it reduces hunger levels.

Introduction to the brain

This week we will discuss some aspects of the brain and its relationship with the other organs of our body. The study of the brain and nervous system, neuroscience, probably began when scientists such as Luigi Galvani discovered the role of electricity in nerves and muscle contractions. Since then, and especially in the last 100 years, neuroscience has progressed immensely, and in doing so, it has also become an incredibly sexy subject.

We can find articles that describe our brain in love, we can admire works of art that represent the brain, and of course, we can watch TV series and movies that contain references to the brain, the mind, and neurosciences. When thinking of the brain, you will probably imagine its role in the functions that make us truly human, such as memory, language, emotions, or learning.

But not everybody knows that the very same brain is also responsible for other functions that we might regard as automatic, such as regulation of wakefulness, temperature, or feeding behavior.

Many of these functions are regulated by the hypothalamus, a tiny area of the brain about the size of a pea that links the nervous system to the endocrine system and therefore has enormous importance for the topics we will discuss in this course.

The brainstem, an area found in the posterior part of the brain and that is continuous with the spinal cord, also contains areas that regulate vital functions such as the heart and breathing rate and controlling the sleep-wakefulness cycle.

I have been talking about the brain for about a minute, and I already mentioned the word "area" twice. What are these brain areas? Do they work alone or are they connected in a network? The latter question is quite important and has been debated for at least two centuries with the mainstream theory changing multiple times in the light of new discoveries.

To explain it, we can start by thinking about the term we sometimes use as a synonym for brain: Grey matter. What we call gray matter are actually areas packed with the cellular bodies of the neurons, the part of the cell that contains the biochemical machinery and the cell nucleus.