Is Caffeine Bad For You?

Ever wondered what gives your morning cup of joe its magical kick? From its ancient origins to its modern-day ubiquity, caffeine has captivated humanity for centuries. Join us as we unravel the science, culture, and secrets behind the world’s favorite buzz. 

Shownotes: yournutritionprofs.com

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Transcript

Get ready to dive deep into the world’s favorite stimulant – caffeine. Whether you’re a coffee connoisseur, a tea enthusiast, or someone who simply enjoys a good energy boost, you’ll discover fascinating insights about how caffeine works, its benefits and drawbacks, and the surprising ways it influences our brain and body. 

M: I’m Professor Megan 

S: and I’m Professor Susan, and we’re

Both: Your Nutrition Profs!

M: We are registered dietitians and college professors who have taught more than 10,000 students about health and nutrition. We have answered a LOT of questions about nutrition over the years – 

S: Some questions we get asked every year and some are rarely asked but very interesting.

M: We’re here to share our answers to these common (and uncommon) nutrition questions with you.

S: So bring your curiosity and let’s get started. 

Both: Welcome to our class!

S: Welcome everyone! We hope you’re all doing well and we also hope that you celebrated National Asparagus Day last week! 

M: I love a day devoted to a vegetable! We posted a bonus episode last week all about asparagus so make sure to check it out.

S: Please do. Ok, today we’re discussing a topic that fuels our mornings and maybe our afternoons too…. caffeine – everybody’s favorite!

M: That’s right, maybe your caffeine of choice is coffee, or tea, or maybe you like an energy drink?

S: I have to have a cup of coffee every morning to get my day started. 

M: Well you’re definitely not alone! About 90% of American adults consume caffeine regularly. It’s the most widely consumed stimulant in the world!

S: In the world?

M: In the world! 

S: Wow! Well, caffeine occurs naturally in over 60 plants but it’s most common in things like coffee beans, tea leaves, cacao pods, kola nuts, and guarana plants. Synthetic caffeine is available too and it’s manufactured in a lab and synthetic caffeine can be found in some prepackaged foods, some drinks and even in pill form. 

M: In the plant it works as a natural pesticide which basically protects it from being eaten by insects. The younger the plant the more caffeine it contains. 

S: Well that makes sense because you want to protect the babies.

M: Of course! 

S: You can also find high concentrations of caffeine in the soil around those plants like coffee plant seedlings. It’s thought that this helps prevent the germination of other nearby seedlings, and that reduces competition for resources and give the baby plants a better chance of survival.

M: I love learning about how plants protect themselves! 

S: I do too!

M: Well, we’ve been consuming caffeine for thousands of years. It was first discovered in China around 1000 B.C.E. in tea. Early civilizations like the indigenous people of South America and the Arabian peninsula were among the first to cultivate caffeine-containing plants. And they were used in rituals, ceremonies, and even as medicine.

S: It’s reported that Ethiopians were the first to recognize the use of coffee beans to make a stimulating drink. 

M: So we’re going to refer to them as coffee beans, but what we know as “beans” are actually the seeds of a cherry-like fruit called coffee berries.

S: That’s a really good point. 

M: Yeah, but let’s get back to the history! 

S: Yeah! Ok, there is a famous story of how coffee was founded in Ethiopia by a goat herder named Kaldi around 800 A.D. His goats ate some of the beans and began to act strangely , like energized and excited. So he thought, I’m going to try the beans myself! So he did and he felt those same energizing and exciting effects. So Kaldi took some of the beans to some local monks. The monks took one look at the beans and exclaimed that that was the work of the devil and they threw the beans into fire. But as the beans roasted, they released a beautiful, heavenly aroma. So the monks pulled them out of the fire and crushed them up into embers. 

M: And the monks stored these embers in a jug with hot water to preserve them. Later they decided to drink this new concoction and they realized it helped them stay awake during nightly devotions and prayers, so basically… a miracle! And coffee was born… or maybe not. 

S: Or maybe coffee was discovered by someone from Yemen? According to another legend a Sufi mystic was traveling through Ethiopia on spiritual matters. He saw some very energetic and enthusiastic birds eating the fruit off a plant. He was exhausted from his journey so he decided to give these berries a try for himself and he did find that they gave him energy. So were birds and a Yemenite mystic responsible for the discovery of coffee?

M: Well, we’ll never know for sure, but Ethiopia is largely considered the birthplace of coffee.  Coffee plants were grown all over the Arabian peninsula including Yemen and Somalia and coffee is sometimes referred to as the “wine of Araby”. 

S: Ethiopians and their neighbors the Eritreans often treat guests to an important coffee ceremony called Habesha where the beans are prayed over and roasted several times and then the coffee is brewed and then they share it. It’s considered a symbol of friendship, respect and great hospitality. I’ve actually been fortunate to have been at several of these ceremonies with my Ethiopian friends.. The ceremony lasts about 90 minutes and while the coffee is roasting and brewing, you talk and laugh and have nice conversations. And the coffee is good but it is super strong! I mean, I can only drink a little tiny bit of it and I still feel super jittery and a little bit… nervous.

M: Well I still want to try it. 

S: Oh my gosh, if you get a chance to go to a coffee ceremony it’s really something special. 

M: Well, caffeine quickly became intertwined with cultural practices and social rituals in many societies. In the Middle East the first coffeehouse opened in Constantinople (which is now Istanbul) in 1475, and coffeehouses emerged as centers of social and intellectual exchange and were often called “Schools of the Wise”. And they’re still very popular today.

S: Coffee hit Europe first in Italy where it was imported from the Ottoman Empire. The first European coffee house opened in Venice in 1645. Use spread to the British isles and to France a few years later and then to the rest of Europe, but it was primarily the wealthy who could afford such a drink. Tea was much more commonly consumed.

M: In the New World coffee was available but was not very popular, that is until the Boston Tea Party. Once all of the British tea was thrown into the Atlantic it became unpatriotic to drink it, so coffee became the American drink of choice. 

S: That’s a really cool story.

M: Yeah.

S: It began to be grown in the lush regions of Central and South America. And today Brazil is the world’s biggest coffee producer.  

M: So in East Asia, it was not coffee but tea that became the caffeinated beverage of choice. In fact, tea ceremonies came to include elaborate rituals, steeped in tradition and cultural symbolism. So far beyond just a cup of tea, these ceremonies hold profound meaning, and emphasize respect and mindfulness.

S: With the Industrial Revolution, caffeinated beverages became more accessible. Technological advances like coffee roasting machines, tea processing techniques, and modern brewing methods all contributed to the widespread use of caffeine. 

M: And caffeinated beverages are used to allow people to stay awake and pray, meditate, and reflect on the world. It sounds pretty good to me!

S: Me too!

M: Caffeine is a naturally-occurring psychoactive chemical with the formula C8H10N4O2. Its scientific name is 1,3,7-trimethylxanthine.

S: That’s a pretty big mouthful, let’s just call it caffeine. 

M: Yes!

S: And as we said it works in the body as a stimulant of the central nervous system. So that means it speeds up messaging between the brain and the rest of the body. 

M: Caffeine can easily cross the blood-brain barrier. Once inside the brain it blocks the effects of a neurotransmitter called adenosine whose job is to promote relaxation and sleep. So if adenosine is blocked, you won’t get drowsy and you’ll stay more alert. 

S: Caffeine also causes the release of other neurotransmitters like dopamine and norepinephrine. These are associated with the stimulating effects of caffeine, things like  improved mood, increased energy, and enhanced cognitive function. 

M: I love these benefits!

S: Me too! And it only takes about 15 minutes to start to see these effects after consuming something with caffeine, and these effects can last for several hours. Scientists measure how long a substance works by measuring what’s called its half-life. This is the time it takes for the body to eliminate half of a normal dose. 

M: For caffeine, in adults the half-life is 5-6 hours.  But this can be altered by many different factors like age, body weight, whether or not you’re pregnant, the medications you may take, whether or not you smoke, and, of course, your genetic make-up. 

S: Right. For example, smoking speeds up metabolism of caffeine so it leaves your bloodstream sooner, but pregnancy or use of oral contraceptives slows down caffeine’s metabolism. In fact, during the third trimester of pregnancy, caffeine can remain in the body for up to 15 hours!

M: That is a very long time! 

S: Yeah.

M: But your genes are really important too. About 25% of people metabolize caffeine much more slowly so the caffeine stays in their system longer. We actually talked a little about this in our nutrigenomics episode. 

S: We did! I mean, based on my genes I’m a normal metabolizer of caffeine so the half-life for me is probably about 5 hours, but my husband is one of those slow metabolizers. So his caffeine half-life could be something like 8-10 hours. 

M: That’s so interesting! My husband and I are the opposite! I’m the slow metabolizer and he’s the normal metabolizer. 

S: Do you notice that it stays in your system longer?  

M: No, I don’t! 

S: Ok?! 

M: Not really, but that doesn’t mean that it’s not happening at a, you know, cellular level in my body!  

S: Right. 

M: Man, nutrigenomics is fascinating! 

S: It really is! Well in the liver, caffeine is metabolized by the cytochrome p450 enzyme system. 

M: We talked about this system too, when we talked about the interactions between grapefruit and heart medications!

S: Oh yeah, I remember that episode. So this cytochrome p450 system metabolizes lots of drugs including caffeine and grapefruit inhibits it. 

M: Right. And this system (if you haven’t had any grapefruit) also metabolizes caffeine. 

S: But caffeine’s effects go way beyond just being a pick-me-up.

M: True, there are several different effects. But let’s start first with cognitive function. Research suggests that moderate caffeine (and we’ll define what moderate means in just a bit)... but moderate intake has beneficial effects on memory, reaction time, and executive function – so things like organization, planning, and time management. 

S: Well I would agree with that. 

M: Me too.

S: I feel like it does help me stay focused and get things done! I also, though, feel the effects on my cardiovascular system after I consume it.

M: Right. So within a few minutes the caffeine in your favorite beverage can cause the release of substances called catecholamines… substances like adrenalin. 

S: When adrenalin is released in the body, like when you’re scared or nervous, it causes a cascade of reactions and this is called the fight-or-flight reaction – you may have heard of that. Caffeine can cause this too. 

M: Yes, and fight-or-flight reaction means just that – it’s getting your body ready to fight something or someone, or to run away. So the body readies itself by increasing heart rate, breathing rate, and blood pressure to send more oxygenated blood around to the muscles. 

S: So if you’re going to fight or run away from someone you’ll also need fuel.

M: Yes.

S: So fat from your fat stores gets dumped into your bloodstream and energy use goes up. 

M: These are the same things that happen when you exercise. So often “pre-workout” supplements contain high levels of caffeine, which “jump starts” this process and gets you pumped up for a workout. 

S: And it can also help you during exercise, because it stimulates the central nervous system and increases fat use. This means it can reduce fatigue and something called perceived exertion, which is how hard you think you’re working, so you don’t feel as tired. 

M: And reaction time, hand-eye coordination, and peripheral awareness all benefit from a little bit of caffeine. So even more reasons to use it to help enhance your athletic performance. There are studies showing that a dose of caffeine can improve sprint times and basketball shooting accuracy. 

S: That’s really cool.

M: I know!

S: And if all of that isn’t enough for you, some studies suggest that moderate caffeine consumption may be associated with a reduced risk of some cancers like liver and colorectal. Other studies show benefits for conditions like Parkinson’s and Alzheimer’s.

M: But….

S: There’s always a but…

M:  Yeah..  Benefits of caffeine are based on “moderate consumption”. Remember, we mentioned that earlier. Well, the FDA considers no more than 400 mg per day a safe amount for healthy adults to consume. 

S: And, of course, you don’t have to drink coffee or tea to get your caffeine fix. You can consume it in chocolate, sodas, energy drinks, over-the-counter tablets – any of those, but coffee beans are still the #1 source of caffeine in the world. 

M: And the amount of caffeine in a cup of coffee varies from about 40 mg to 170 mg based on several different factors. 

S: Right, like type of bean, or how the coffee is brewed, or how long it’s been brewing….

M: Yes. But a general rule is that an 8 oz cup of coffee contains about 100 mg of caffeine.  

S: So if you’re going to meet the definition of “safe” for healthy adults, no more than 4 cups of coffee a day would be recommended.

M: And as we mentioned, people have different responses to caffeine. If you drink a cup of coffee every morning, you may build up a tolerance. This means that the beneficial side effects that you’re looking for can decrease and it will take more and more caffeine to get that desired effect.

S: Right, so 2-3 cups instead of just one to get you up and going in the morning. 

M: Right. But really high doses of caffeine can cause negative consequences, even death!

S: Well that makes sense – the dose makes the poison. 

M: Yeah. Most studies show that intakes of 1000-1200 mg in a single dose can cause convulsions, vomiting, and paresthesia which is a sciencey word for tingling or that pins and needles feeling in your extremities.  

S: And some people might have some medical conditions that they are not aware of, and excessive caffeine can cause things like cardiac arrest. 

M: Absolutely but even consuming doses between 400-700 mg can cause restlessness, irritability, nervousness, a rapid heart rate, palpitations, and even tremors. 

S: I notice that I get restless and irritable if I consume Starbucks coffee! I mean, according to the website, because a 16 oz grande of their regular coffee has 260 mg, and a 20 oz venti has 340 mg! So I’m used to just making my own coffee with K-cups… so a regular coffee for me probably only has 100 mg which is why Starbucks makes me a little jittery.

M: Yeah, fancy coffees like cappuccinos or lattes have less caffeine because they have less coffee and usually more other things like milk and foam, but they can also potentially have more calories. I like the grande iced latte and it only has 150 mg of caffeine.

S: Tasty. Teas and sodas tend to have less caffeine than coffee, but of course that can vary too based on type of tea or brand of soda. 

M: Panera Bread has been in the news recently due to their “Charged Splash” lemonade drinks.

S: Oh right, I mean I heard they had some lawsuits because people actually died.

M: Yeah, a 21-year-old college student in Florida drank 3 of these Charged Splash drinks and had a fatal heart attack while walking home. 

S: Wow!

M: And similarly, a 46-year-old man also in Florida died of cardiac arrest after he also drank 3 of these. 

S: So don’t drink those in Florida! Well the Panera website says there are 237 mg in a 30 oz serving of these Splashes. So if you drank 3 that’d be over 700 mg of caffeine.

M: Wow! 237 is more than in most energy drinks. An 8-oz Red Bull has about 100 mg of caffeine, while the sugar free version has about 80 mg. But other than Red Bull most energy drinks are 16-oz and contain about 200 mg. But sometimes the problem is something called “stacking”. And this means consuming caffeine continually throughout the day until you reach a toxic level.

S: Right. So those two folks drank 3 fairly close together. So that was 700 mg in a really short period of time. But sometimes you might stack, like Megan said, where you have 1 to 2 cups of coffee in the morning, a little later in the day you have a soda, maybe you have a tea or Panera Splash for lunch, maybe then in the middle of the afternoon you have coffee or soda as a “pick-me-up”, and then you go to work out and you have a pre-workout supplement. So that can add up to a lot more than the 400 mg that’s considered safe for most people. 

M: Yeah and we haven’t even discussed caffeine use in kids. While they’re probably not drinking coffee in the morning, they might drink sodas or tea – and they’re probably eating chocolate. 

S: Most kids eat chocolate.

M: Yeah. 

S: Well the FDA recommends that children under 12 avoid caffeine from beverages like sodas or teas. They really don’t mention chocolate, but honestly, there’s really very little caffeine in most chocolate. 

M: Yeah.

S: So they should be ok.  

M: And the FDA says teens should limit their intake to about 100 mg per day and avoid energy drinks.

S: Right….like that’s happening. I mean, according to the CDC up to 50% of adolescents report consuming energy drinks, and over 10% of secondary schools sell energy drinks in vending machines and snack bars. 75% of school districts in the U.S. do not have a policy in place regarding energy drinks. 

M: And since energy drinks became a “thing” about 2007, there was a 10-fold increase in emergency room visits related to their consumption between 2007 and 2011. 

S: 10-fold! 

M: Yeah! 

S: That’s crazy. I mean, caffeine can also be hidden in products like appetite suppressants and over-the-counter pain relievers and cold medicines. So make sure you check the labels and look for pseudoephedrine. Especially if you’re also consuming beverages that contain caffeine. 

M: That’s really good advice, but unfortunately not all labels will list the amount of caffeine in a food or beverage.

S: That’s so true.

M: Yeah, so you may have to do a little digging. 

S: Right. The Center for Science in the Public Interest or CSPI has a pretty nice chart with caffeine amounts for several different items. We’ll link that in our show notes at YourNutritionProfs.com.

M: Let’s talk a little more about the effects of caffeine, which are not all positive. We’ve talked about the negative consequences of high doses. But even moderate doses can cause things you may not want. 

S: True. For one, caffeine is a diuretic. That means it makes you have to pee more often so you lose water and some electrolytes. This can be dehydrating, especially if you’re also exercising or in a hot environment and losing water through sweat. 

M: So you wouldn’t want to consume a caffeine-containing beverage without also consuming lots of plain water – especially before and during exercise. 

S: That is really good advice! Especially if you use something like pre-workout. 

M: Yeah. Caffeine also increases the release of stomach acid and can relax the lower esophageal sphincter which is that circular muscle between the esophagus and the stomach. Many with GERD or gastroesophageal reflux disease are told to avoid caffeinated beverages like coffee or soda.

S: You know it doesn’t work for everyone with GERD, but if you suffer from it, try avoiding caffeine to see if it helps with your symptoms. 

M: And what about headaches? Some headache pain relievers like Excedrin contain caffeine. Why? Well, some headaches are caused by dilation or swelling of blood vessels in the brain. They expand into surrounding tissues, and that can trigger pain. Caffeine can narrow these vessels which can ease or even reverse some headache pain. 

S: But…. caffeine may be a headache trigger for other people so then it would need to be avoided. And if you’re a frequent caffeine user, and you stop for a couple of days, a headache is a common side effect of caffeine withdrawal. 

M: Right. If you’re trying to quit caffeine, other withdrawal symptoms include tiredness, sleepiness, difficulty concentrating, and well, crankiness. The good news is that these withdrawal symptoms usually subside after a few days.

S: So who should avoid caffeine? Well we’ve already discussed children and teens. Others who should avoid or limit their intake include women who are pregnant, breastfeeding, or trying to conceive. 

M: Also those who are prone to anxiety or panic attacks, those with gut or digestive conditions like IBS or GERD like we mentioned before, those with heart conditions, as well as those with sleep disorders should probably avoid caffeine. 

S: Caffeine can also interact with some medications, so beware. Especially if you take meds for things like thyroid disease, osteoporosis, blood pressure, asthma, diabetes, or if you take antidepressants. 

M: Definitely check with your doctor or pharmacist about your particular meds and their possible interactions with caffeine. 

S: So what’s the future of caffeine use? A lot of changes are happening. One change is the rise of what are called “functional beverages”. There are all sorts of examples of these, from things that are considered performance-enhancing sports drinks to relaxation-promoting drinks that are infused with caffeine and other bioactive compounds like adaptogens. 

M: And what about alternative sources of caffeine? According to some estimates, because of climate change, by the middle of this century 50% of the land currently growing coffee plants will no longer be suitable for coffee production. 

S: 50%?!

M: I know! 

S: So I guess we’re going to reduce our production of coffee and tea…

M: We’ll have to!

S: But maybe we can get caffeine from other plants like guayusa or yerba mate – these are used to make teas and they’re super popular in South America. You can also get caffeine from yaupon holly which is the only indigenous caffeine-containing plant in North America, and it grows in Texas 

M: Nice! There is also the development of new and innovative synthetic caffeine which can be added to coffee and tea-like beverages without actually having to grow the plant at all.

S: That could be interesting. And of course, there is always personalized nutrition for consumers. Maybe you want to boost memory, focus, and productivity.  Well in the future, someone might make a caffeine-containing supplement just for you based on your genetic profile and your lifestyle. 

M: So what’s the bottom line for caffeine?

S: Ok, bottom line, caffeine is the most commonly used stimulant in the world and its use can be traced back to 1000 BCE. When consumed in moderation it can improve alertness, cognitive function, even athletic performance. There’s even evidence of reduced risk of some chronic diseases. 

M: Moderation means less than 400 mg of caffeine daily and an 8 oz cup of coffee typically has about 100 mg. But you can build up a tolerance to caffeine and even experience withdrawal if you suddenly stop consuming it.

S: Negative side effects of caffeine can include restlessness, insomnia, anxiousness, and heart palpitations. Some people are more sensitive to caffeine than others and may experience these even at low doses. 

M: And there are some people who should probably avoid caffeine altogether including children, adolescents, those who are pregnant or breastfeeding, prone to anxiety, or have certain health conditions and it can interact with some medications.

S: But if you do enjoy your morning cup of coffee or reach for an afternoon soda or energy drink to get through your day, remember to listen to your body and consume caffeine responsibly.

M: Ok, that’s it for today. Thank you all for listening. We hope you learned a little something about caffeine. 

S: Join us next time to hear about an amazing human organ… the placenta. 

Both: Class dismissed.

S: We hope you enjoyed this episode. You can find the show notes and a list of sources on our website, yournutritionprofs.com. 

M: Your homework is to follow us at your nutrition profs on Instagram and to listen to our next episode. You can listen on Amazon Prime, Apple Podcasts, Spotify, YouTube, or anywhere podcasts are found. We’d appreciate it if you’d “like” us, write a review, subscribe, and invite your family and friends to join us too. 

S: If you have a nutrition or health question you’d like answered, let us know! We may even do a show about it! Send an email to yournutritionprofs@gmail.com or click on the “Contact Us” page on our website.

M: Thanks to Brian Pittman for creating our artwork. You can find him on instagram @BrianPittman77

Both: See you next time!