Anita Rao
The Raos are a tea drinking family. My mom averages about five cups a day, and is the proud owner of 30 different tea pots. I grew up on English black tea made with ginger and chai masala. But in college, I turned my back on my roots in a big way.
I started drinking coffee. At first, it was occasional — when I needed to stay up late to finish a paper, or wanted a jolt to make it through a Friday morning class. But by the time I was out in the world adulting at my first journalism job, I was drinking at least two cups a day. Coffee just comes with the job title — it's not right to abstain in this profession.
But lately, I've been faced with a serious conundrum: Coffee is hurting my body, literally. I've had acid reflux on and off for about three months, and all signs are pointing to coffee as a major contributing factor. Coffee is delicious, interesting and complex, and I want to be a part of coffee culture. So, what is a gal to do?
This is Embodied, our show tackling sex, relationships and your health. I'm Anita Rao.
Dr. Satish Rao
The black coffee can have important effects on esophageal function and gastric function. And people who are sensitive, then this can become troublesome.
Anita Rao
The upside of my coffee conundrum is that there is no shortage of stomach experts in my life. You just heard from one of them: my dad. For those of you who are newer to Embodied and haven't met him yet, he's a professor of medicine at Augusta University and a specialist in gastroenterology. He's one of two gastroenterologists I have on speed dial. The other is my brother-in-law. Conversations with both of them are helping me find a workable solution. But it also made me really curious about the science of coffee and how it affects our body from top to bottom.
So, we know that coffee affects the gut somehow, but the burning question that everyone has is about coffee and poop. And when we started looking this up as a team, we realized that your name actually kept popping up. So it turns out, what, you were one of the first people to really study this. So, take me back to the 90s and the experiment that you ran on coffee.
Dr. Satish Rao
When I first came to US, I was very intrigued by the amount of coffee that people take. And, when I started encountering patients, they would say, "Well, you know, Doc, if I drink a cup of coffee that makes me go to poo." I said okay, but there is no evidence of this in the literature. So, we decided to study carefully and methodically: does coffee have a stimulative effect on the gut? And if so, how does it compare with decaf coffee? And how would it compare with a meal? And so on. So, we designed an experiment to really study this.
Anita Rao
And what did you find out?
Dr. Satish Rao
So, we found that caffeine — coffee — has as much potent effect in stimulating colonic motility as a meal. Meal is by far one of the strongest physiological stimulants for gut motility, particularly colonic motility. But, the effects of a meal can last between two to four hours. But for the first hour, the effect of coffee is almost as equal to the effect of a strong meal. There is also an effect of decaf coffee, but that's about half that of regular black caffeine-containing coffee. And hot water has very minimal stimulant effect on the colon.
Anita Rao
So, coffee increases the contractions in your gut that pushes the stool to the rectum. It causes this whole system to really wake up. It goes to the small intestine, to the colon; you eventually have a bowel movement. So we have a sense of what coffee does to the gut in the colon, but there's still this open question about why coffee has this effect. And we're not exactly sure. So, tell me about some of the prevailing theories.
Dr. Satish Rao
So, I think it is unclear precisely which ingredient in coffee is really contributing to this. But, as I said, coffee has many components, including theophylline, which is also a component that is present in tea. And, theophylline and caffeine have potent effects on gut motility. They increase gut motility. And, some of these effects are directly: as the coffee or tea goes through the gut. And, some of this is indirectly: after they get absorbed and through the bloodstream, they have an effect. But more precisely, which chemicals or which neurotransmitters are affecting gut motility, I don't think we fully understand.
Anita Rao
So, you say it's also important to keep in mind that there are other parts of our morning routine that could also contribute to why our colons are so revved up after that morning cup of coffee. So, tell me about what's going on there — what's going on with our colon in that morning time?
Dr. Satish Rao
So, colon is awake 24/7. But, when we go to sleep, the colon also goes to sleep. But the colonic activity does not go to zero. It diminishes significantly, but as soon as we wake up in the morning, the colon activity increases almost threefold. And, this response lasts for up to an hour to an hour and a half. And during this time, the colon also induces very strong contractile events called high amplitude propagating contractions, or HAPCs, that move a large column of stool and deliver it into the rectum. Which, in many people, then induces a desire to go and have a bowel movement. So this is often the trigger for early morning bowel movement. And, this is really an inbuilt bio-rhythm that is active in most of us. In some people it could be a little later in the day, some people it's in the evening, but this is one of the natural triggers of bowel movement.
Anita Rao
So, the bowel is moving, the bowel reacts, but there's, in the stomach — I guess, before we're getting to the colon — the stomach has a response to coffee where it creates this increased level of gastric acid. Is this why coffee can lead to acid reflux and digestion? Or, help me understand why it is that folks have some trouble with coffee.
Dr. Satish Rao
So, coffee has at least a dual effect in the stomach. One: The effect of coffee and its contents in stimulating acid and gastrin production in the stomach. And the second, is a, kind of, a direct effect, again, of caffeine and coffee on stomach motility and lower esophageal sphincter function. So, the LES, or the lower esophageal sphincter, is like a one-way valve system that allows food or drinks to go down from the food pipe of the esophagus into the stomach, but stops material from the stomach backing up, or refluxing, back into the esophagus. But several experiments have been done where we have carefully assessed the LES function before and after coffee intake. And we have seen that the lower esophageal sphincter becomes temporarily, or transiently, weak after intake of coffee. So the LES becomes more relaxed after coffee, and this allows more of the contents of the stomach to reflux into the esophagus, leading to heartburn or acid reflux simply.
Anita Rao
There you have it. My lower esophageal sphincter weakness is currently really cramping my coffee habit. Thanks, Dad. And, we'll be talking more about that soon.
Eric Hodge
I'm Eric Hodge, host of Morning Edition here at WUNC, and I have a deeply meaningful relationship with coffee. I love the smell when you open the bag, and I love the smell when you grind it, and the smell that blooms in the room when you add all that hot water. I get to work at about four in the morning, but I don't make coffee until about 5:30. So, I guess I'm not really using it to wake up; although, it does make me feel a little sharper and maybe a bit more alert.
Kara Abare
I try to deny that coffee has any impact on my mood, but my husband jokes, kind of, that we need to get coffee in me if I seem to be having an off morning. And, if I'm being completely honest, it usually does help because most of the time I feel that rush of energy or that even pure joy feeling about halfway through my cup. Which kind of sounds weird now that I say it, but it's true.
Jacob Moore
When I can manage to do it, it's a nice way to start the day. Just, by focusing on the coffee, and the morning light, and the quiet before the day gets going.
Ellie Gardner
I would definitely consider coffee one of my best friends. That's the best way I could describe the relationship. Love drinking coffee everywhere — out at cafes, with friends — really the place doesn't matter. But for me, coffee is definitely a ritual. I do enjoy it alone, but I really also enjoy it and the associations of coffee. Probably, that's why I love coffee. I say coffee is one of my best friends, because I usually enjoy it with my best friends, now that I actually think about it.
Anita Rao
That's Eric Hodge, Kara, Jacob and Ellie. They, like the majority of Americans, are coffee lovers. Our country consumes more of the substance than anywhere else in the world — like 400 million cups a day. According to many pop science articles that pop up on my news feed, this habit is good for our health. But, how true is that? I put my questions to an expert, who you may recognize from her viral YouTube series.
Dr. Shannon Odell on Youtube
The majority of Americans are addicted to caffeine. But, have you ever wondered what exactly is going on in your body as you desperately grab for that cup of coffee in the morning? I'm Shannon and I'm a neuroscience PhD candidate, and this is Your Brain on Caffeine.
Anita Rao
Shannon Odell knows her science — and how to separate the signal from the noise.
Dr. Shannon Odell
I feel like I am constantly seeing it on my Twitter feed, like, "A new study shows caffeine does X, Y and Z," or "Coffee does X, Y and Z." So, when we think of a typical scientific study, we would think, like: okay, we give people coffee, you know, twice a day for three years, what happens to them? We're not doing that.
A lot of these studies are what we call observational studies. So, in an observational study, what you do is, you basically take a large cohort of people, and you ask them lots of questions. You might trace them over a long period of time; you're not manipulating any kind of variable, right? A lot of these, kind of, "coffee reduces your risk for X, Y, Z," come from these observational studies, where we're basically just asking you a bunch of questions. We're trying to, you know, make sure that we control for things like, lifestyle, or age, or all these other variables. But with that, there's always the chance that we're missing something. So we can't exactly show causation with observational studies. That said, with coffee, there are a lot of observational studies. So, I think that is promising in itself, right. When you're getting the same result over and over and over again, that seems to show that there's probably some evidence there. But still, we don't have the exact causation down.
Anita Rao
So, we aren't sure that it's long-term coffee consumption, in particular, that's causing your brain fog to clear or helping your heart. But, what we do know with great precision, is how coffee operates in your body short term.
Dr. Shannon Odell
So caffeine works on the adenosine system in the brain. So, what is adenosine? As our bodies are kind of going through their day-to-day functions, it utilizes energy in the form of this molecule called ATP. And that molecule gets broken down, and that's why we have the energy that we have. And, when that gets broken down, it releases this molecule called adenosine. So, adenosine is almost a marker of all the energy that we're using throughout the day. And what happens is, when this adenosine builds up, it binds to these receptors in the brain called adenosine receptors. And what it does is, it actually signals sleepiness. Yeah, it kind of makes sense why we get tired throughout the day, and especially on days when we're, like, utilizing a lot of energy. We're extra tired, we're feeling extra sleepy. So, what caffeine does is, it actually binds to adenosine receptors. It just sits on the adenosine receptors and doesn't let adenosine make its way through. It's called a competitive antagonist. So, what it does is, it blocks the action of adenosine — allowing us to stay alert and awake.
Anita Rao
Okay, so caffeine basically prevents the sleepiness effect from hitting the body. And we all know that physical experience of that, that feeling of being extra alert after a cup of coffee, and that's also because coffee kind of activates our fight or flight response. Tell me about that.
Dr. Shannon Odell
Yeah, so caffeine is an awesome molecule in that it can do a lot of different things. Caffeine can also act peripherally. It can prevent the breakdown of a certain messenger in the body known as cyclic AMP. It tells your body to produce epinephrine and norepinephrine, you know, those adrenaline and noradrenaline molecules. So, by caffeine preventing the breakdown of cyclic AMP, you're getting this increase of this epinephrine and norepinephrine — aka that fight or flight response. So, that's why you feel those caffeine jitters. I know I'm even feeling that right now, I kind of had a lot of caffeine this morning. So I can even feel it in my my own hand as I'm talking.
Anita Rao
So tell me about that — I mean, what the science behind how caffeine affects our bodies differently. Because you could have a cup of coffee and I could have a cup of coffee, and an hour later, we might be in very different states of mind. So, talk to me about why it's so different person to person.
Dr. Shannon Odell
Yeah, it's incredibly different person to person. I think sometimes, people don't realize that. So, they see someone, you know, who doesn't drink coffee in the morning, and they're like, "How do they do that?" Or, you know, they see someone who drinks three cups of coffee, and they're, you know, a one cup of coffee person. So it's because of genetics, and also our experience with coffee. So people are going to metabolize coffee at different rates, so that's going to affect how long coffee stays in your bloodstream. But there's a lot of diversity in, maybe, how many adenosine receptors that you have in your brain. And that can be affected, also, by your experience with coffee. So yeah, it's very different person to person.
Anita Rao
As we've been saying, there are many other compounds in coffee in addition to caffeine. If we want to get real science-y, there are more than 1000 chemical compounds in coffee. And some of those are antioxidants. I know that antioxidants are good for me, and I know that they're in blueberries, but my knowledge stops there. So, back to Shannon.
Dr. Shannon Odell
You know, you hear the word antioxidants, you say, "Okay, good, I want that." And, what goes hand-in-hand with antioxidants are these things called free radicals. And I think we hear free radicals and we think, "Okay, I don't know what those are, those are bad, we do not want those." So, what's interesting about free radicals is, yeah, they're not great, but they exist all around us. Our bodies produce free radicals. We get free radicals from the environment, free radicals from the sun. But, the problem with free radicals is — to get a little bit specific, and a little bit chemistry-esque — they have an unpaired electron. And all we need to know about that is, unpaired electrons are bad. Electrons really want to be paired.
So, what happens is, the free radical goes around our body, and it's looking for an electron, and it will steal it from wherever it can find it. Which is bad, because then it creates a different free radical. Maybe it steals it from a cell membrane, and, all of a sudden, our cell membrane has one less electron. Maybe that changes the conformation of the cell membrane, maybe different molecules can get into that cell membrane, right. So, we don't really like free radicals because it, kind of, steals electrons from a different place, and it kind of messes things up. And over time, this is called oxidative stress. And, we know oxidative stress can be linked to a lot of different diseases, from, you know, Alzheimer's, to Parkinson's to heart disease.
So the question is, where do antioxidants come into this? Well, antioxidants are great, because they're basically electron donors. They have an extra electron lying around, and they're happy to give it to these free radicals. And, when they give it to these free radicals, it doesn't cause a problem — they don't become free radicals themselves. So what we love is when antioxidants come in, and they give these free radicals — the free radicals can't mess with our body. So overall, we have this idea that antioxidants are really great for us. When we look at the data, it becomes a little bit more confusing though. We think, in theory, that antioxidants are really great. And, there's lots of studies that show we want to increase our antioxidants in our diet. But the nitty gritty of how the mechanism works and how it will actually prevent disease, it's a little murky.
Anita Rao
I wish I could carry Shannon around in my pocket and have her explain food and nutrition science whenever I needed it. Because if our deep dives on diet culture earlier this year taught me anything, it's that we should be paying as much attention to who is interpreting the data as to what the data is itself.
Dr. Shannon Odell
I think, the things that you're always looking for in these studies is, you want to look at — what is the group size? Did they look at 100 people? Did they look at 10 people? Did they look at 100,000 people, right? So, a larger group size is going to mean it's going to have a little bit more weight. Another thing you can look at is, there's sometimes one-off studies versus, we have these things called, systematic reviews or meta analyses. So, systematic reviews and meta analyses really hold more weight, because what they're doing is, they're actually looking at the effect of many studies repeated over and over and over again, and then looking at its overall effect. And then of course, you always just want to look at — if you're looking at a headline — you always want to look at the source. Sources that are coming directly, you know, from the scientific institutions themselves, sometimes those can be a little inaccessible. You always want to make sure — is this article that's anti-coffee, but the article is being paid for by Big Tea, you know? You want to look at what kind of sources it's coming from.
Anita Rao
Big Tea, we've got our eyes on you.
Daniel Everhart
Here, I feel like the culture is more kind of, boom, boom, boom, we're on the move. Whereas in Spain, it's a lot of, like, relaxed time sitting, enjoying having conversations with people, or just spending time with yourself enjoying the coffee.
Hmellisa Mlo
Our relationship in America with coffee is definitely very much around work and productivity. And when you go to other countries like Scandinavia, in Sweden especially, they have a word for when you're just enjoying a cup of coffee, and sometimes a pastry with your friends. And, it's called: fika. And, it's like a way of life. My parents are from Vietnam, and my dad was born in coffee country, essentially. And so, over there, it's much more social. And, I like to say that coffee is in my blood, because it literally kind of is.
Anita Rao
You just met Hmellisa Mlo, a listener in New York and Daniel Everhart, a listener in Chicago. Whether you're drinking coffee to speed up or slow down, often varies from place to place. Another person who has coffee in their blood: Samuel Ngwa.
Samuel Ngwa
I got involved in the culture of coffee at the age of five/six, around 1959 actually.
Anita Rao
Samuel was born and raised in Bamenda, Cameroon: a city in the northwestern part of the country. His family owned more than three acres of land. They grew food for themselves and coffee to sell. The coffee beans were ripe for harvest in the dry season, which was around November and December. It's also when most kids are outside playing soccer, and Samuel didn't always have that luxury.
Samuel Ngwa
With coffee culture being part of my family's source of income, it was very difficult for me to differentiate what was a priority to my parents and a priority to me. Mine would have definitely been playing with my friends.
Anita Rao
Exactly.
Samuel Ngwa
But, if you played with your friends and the coffee beans were not picked, you had to answer. And consequently, maybe your fees may not be paid for lack of income. Having said that, when the coffee beans ripen for picking, you just don't go to the tree and brush off every bean you see there. You have to meticulously pick all of the right beans off the branches. And those beans don't get ripened at the same time. So, you can see how painstaking the process was.
Anita Rao
Definitely. So, you really had to learn at a young age the art and the science of when a bean is ripe, and when's the right time to pick it, and help with your family production. And then, I mean, a number of years later you moved to the US; you were trying to get an undergraduate degree at the University of Wisconsin. And, you started noticing that all of these people were walking around carrying these white styrofoam cups. So, tell me about this observation and what you uncovered between those folks and the link to your your experience back home.
Samuel Ngwa
When I left Bamenda, the impact of what I was doing didn't mean anything to me at all. As long as it was out of my sight, well, good riddance, you know. But, when I got to the University of Wisconsin-Stout it was still very cold. Trying to adjust to that around campus, everybody moves very fast, covered up with their coats and backpacks and then white cups in the hand. And that kind of intrigued me to know what it was that everybody had, which I wasn't used to. So, in the student union halls, everybody sitting in tables also had the same thing. And thereafter, I started inquiring what was it that everybody was drinking in those cups. And, it became known to me that it was coffee. Now, it's coffee? Then, it dragged my mind back to what I used to do back home. And it became clear that the coffee we were picking and processing back in Bamenda ends up in far places like, the University of Wisconsin student campus. So, definitely means all over the world, people had coffee.
Anita Rao
Samuel simmered on his white styrofoam cup discovery for a while. And then started to wonder exactly whose coffee cups the beans he had picked as a kid were ending up in. He began to look for some answers to that question in a business law class at Wisconsin, and then built the blueprint for the business he runs today: Safari Pride Coffee. It's a coffee roastery and distributor based in Minneapolis. Before he officially launched Safari Pride, he moved back to Cameroon to get more acquainted with the coffee process. He learned that a lot of the coffee his family had been growing was sold to Europeans as commercial grade coffee, which undervalue the product and didn't provide enough income for the farmer. With Safari Pride, he does it differently, sourcing directly from farms and cooperatives, where he knows everything about how the products are grown and tended to.
Samuel Ngwa
Coffee is a wonderful product, affected by many factors, principally being the soil on which it is grown. If it's volcanic and rich, so ultimately will be the coffee bean that comes from that soil. Then, it is greatly affected by the way the sun rises and sets, the way the wind blows in the morning, and in the afternoon and evening. All of these factors play around with the quality of the coffee that ends up being graded as top coffee beans, from 90% to 100% grade. And, below 70 being useless coffee, or, well, low-quality coffee, as I would say. So, all of these factors are things that caught my interest to now see what Bamenda coffee is, what other coffees around the vicinity of Bamenda is. And eventually, what is grown in Nigeria, what is grown in Congo, what is grown in Rwanda, Burundi, Kenya, Ethiopia, all of these places, which fall within the Coffee Belt. So, with all these variations, it required me to travel to try to pick out the best beans that would fit into the portfolio of Safari Pride Coffee Company. That's how I got to the stage in which I am today.
Anita Rao
Samuel is invested in bridging the gap between his early relationship with the coffee bean and the relationship he wants people in his community to have with coffee as a product today.
Another person very invested in Java: Austin Jeffries.
Austin Jeffries
You know, I started out as just a customer in a coffee shop. And, you know, I spent enough time there that the owner of the place asked if I was free to come on the other side of the counter.
Anita Rao
Austin is the definition of a coffee head. He spent eight years working at Tate Street coffee house in Greensboro and managed the shop for most of that time. He's actively sought out coffee cultures all around the world.
Austin Jeffries
I think, you know, hustle culture, you know, being on that grind — no pun intended — in America is just so prevalent, it really is kind of, productivity and work blends into almost any aspect we really can. I was just in London a couple of weeks ago, visiting my partner there, and I'm sitting at a table, you know, people are chatting with their neighbors, they're meeting with their siblings, they're really taking a moment. And I found that really stark just because, I mean, I was there on vacation. But, I'm seeing people, kind of, in their day-to-day, taking time out to really just relax. It really was apparent to me — you know, not a laptop in sight, you know, not having business meetings — people really just gathering seems to be a lot more apparent in other countries.
Anita Rao
So, you now have this mobile coffee cart, and you set up shop in various locations around Greensboro. I'm curious about the kind of coffee culture you're trying to create with this mobile cart, where you don't necessarily have the infrastructure of a coffee shop where there are seats and tables. Talk to me about how this is different.
Austin Jeffries
Yeah, well, it's definitely a selfish endeavor. My business partner, Gray Johnston, and I were both born and raised in Greensboro, North Carolina. We're both huge coffee fanatics. So, we started out as a passion project just to, kind of, you know, selfishly make some really great coffee for ourselves, but we love the city of Greensboro so much. It really became an opportunity to activate spaces that were lovely to be in but may not have a draw, may not have a reason for people to really linger, relax and connect with their community. So, just about anywhere we can bring the cart and people want to be, we figure a cup of coffee isn't a bad addition to it.
Anita Rao
Have you seen it change people's behavior instead of, kind of, like going in going out and staying on the go? Does it make people interact with the space or linger more?
Austin Jeffries
Oh, for sure. I mean, you know, we're really lucky in that everyone, you know — no one's disappointed to see the coffee guy. So you know, people are always excited walking down the street, turning a corner and suddenly there's an espresso machine and, you know, "I could use a cup of coffee." And, you know, being able to take a moment and reflect, catch-up and, you know, meet somebody new is really gratifying. I mean, both I think for the customer and for me.
Anita Rao
Coffee shops are third spaces — not work, not home — a place to gather and be in community. Lord knows we all need more of that after these last few years. For Austin and Samuel, their relationship with coffee is as much about the process as it is the product. Which means that we can turn to them to bridge the gap between the science and the culture. Aka, how do we get the best tasting and most health promoting cup?
Austin Jeffries
Samuel spoke to, you know, origin of coffee, how much that can affect it. So, I guess, like hopefully any good scientist would believe, get as large a sample size as you can. Explore different regions, you know, there's loads of reviews, papers, critiques of different coffees, try those. And then, just be really mindful of what you're using and how that affects it. I mean, coffee, scientifically, is mostly water, you know, make sure you have a really pure water source. Make sure you use clean equipment, and make sure use a high quality bean — hopefully purchased directly from farmers.
Anita Rao
I love it. Samuel, anything you'd like to add? Any observations about the science that affect how coffee tastes?
Samuel Ngwa
Coffee is extremely a very, very good product, it's one of the most important practices of health. And, since I discovered it drinking in the University of Wisconsin, do you believe that I don't remember which day I have gotten by without least two cups of coffee — minimum. It has improved my health tremendously. I've had some medical issues, but I have rebounded from them so fast. I can attribute that to the amount of coffee I drink a day.
Anita Rao
So, there you have it. A sample size of one, but a testimonial that has me convinced. And if you need more to connect the dots, I tried to pin Shannon down on the big burning questions. Will regular consumption of coffee really increase my lifespan? The most important question.
Dr. Shannon Odell
Oh, it goes against everything in me to say true or false, I can't say.
Anita Rao
You'll say, "Look at the studies, get comprehensive analysis of the data, look at the sample size, and check back with you in a few years."
Dr. Shannon Odell
Choose for yourself. If you feel like your coffee habit is going to increase your lifespan, then absolutely do it. It's not gonna hurt you.
Anita Rao
Embodied is a production of North Carolina Public Radio-WUNC, a listener-supported station. If you want to lend your support to this podcast and WUNC's other shows on demand, consider a contribution at wunc.org now. Incredible storytelling like you hear on Embodied is only possible because of listeners like you.
This episode was produced by me and Audrey Smith. Kaia Findlay also produces for our show, Amanda Magnus is our editor, Jenni Lawson, our sound engineer and Quilla wrote our theme music.
If you enjoyed this show, send it to two of your favorite coffee lovers. You spreading the word about Embodied is what helps new folks find us, and it means so much.
Until next time, I'm Anita Rao, taking on the taboo with you.