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  • Joanna Macmeikan

"Please Stop It" - Why I don't recommend drinking coffee on an empty stomach.


A couple of weeks ago I made a reel on Instagram.


I made it for my people: the handful of patients (who are mostly women since that’s the area I mainly work in), family and friends, and people in my local community who follow my account.


I made it for two reasons:


1. To make people laugh – the audio is pretty funny;


2. To share some information that I find myself regularly repeating in clinic about caffeine and, more specifically, the habit of drinking coffee on an empty stomach. I briefly discussed it from both a Western physiology and Chinese medicine point of view.


As of this writing, that reel has been played more than a million times.


Yep.


I never imagined that it would be seen by so many people and while most people probably liked it because of the funny audio, the message about coffee first thing in the morning seemed to resonate with a very wide audience.


As you would expect, I’ve also had a percentage of people who didn’t like it.


I’ve been called a fraud and a hack, told that I don’t have any qualifications (I hold a Bachelor of Health Science and have studied nutrition, anatomy and physiology and biochemistry as part of my degree), and I have been warned by some particularly earnest individuals not to give people medical advice.


While I hardly think the lifestyle suggestion of “drink water when you first wake up” and “it’s better for your stomach if you eat your breakfast before you have your coffee” constitutes what could be called medical advice, I do realise that I probably owe people a more detailed explanation than the information contained within the caption on that reel.


Hence this blog.


Here I’m going to flesh out some of the statements I made, include some saucy sources for the more scientifically minded, and make very clear which parts of the post are backed by a Western understanding of the body and which come from Chinese medicine theory.


I’ll also provide the names of some much smarter people, who have way more letters after their name than I do, from whom I learned some of this information.


I want to say (and I’ll be reiterating this point) that I didn’t tell anyone to give up coffee. Nor did I say caffeine is bad. In fact, caffeine has been shown to have a number of health benefits.


What I said was that if you drink it as soon as you get up in the morning, you’d probably be better off adjusting the timing.


You don’t have to agree with me. Nor do you have to change any of your behaviours. I’m not the boss of you, so you can gleefully smash down an espresso at 5am if it pleases you.


For those of you reading this blog who didn’t see the reel, here’s the caption:


“Do you drink coffee first thing in the morning?


It’s not the best thing you could be doing for yourself. Caffeine first thing in the morning will inevitably lead to a mid-morning slump (because it interferes with your body’s ability to clear adenosine, a molecule that makes you drowsy) and can really mess with your hormones - not just your sex hormones but your stress response hormones as well.


Chinese medicine considers coffee hot and drying.


Your stomach is full of acid (it’s necessary to help us break down our food) which means your stomach lining constantly needs to replenish itself. Your stomach lining turns over every 4 days and the cells that come directly into contact with digesting food are replaced every 5 minutes! Because of this need for constant renewal against the acidic environment, the stomach prefers moist foods.


Pouring a drying, heating substance into the stomach first thing each morning can injure the stomach and lead to hot conditions like hot flushes, heartburn, bleeding gums, gnawing stomach pain, hunger, bad breath and a dry mouth and throat.


So, what should you do instead? Start the day with a couple of glasses of warm water (you can add a slice of lemon) and then eat breakfast (the stomach loves a warm, wet breakfast like oat or rice porridge) and delay your caffeine intake by 60 - 120 minutes after waking up.”



Caffeine first thing in the morning will inevitably lead to a mid-morning slump:


Caffeine is a stimulant that can delay fatigue and make us feel more alert. Nothing ground-breaking in that statement. But how does it do it?


The main mechanism of action is thought to be the way caffeine interferes with adenosine – a neuromodulator (chemical messenger of the body) that slows down activity in your brain and makes you feel sleepy.


Adenosine builds up during the day in the parts of your brain that control wakefulness. At night after the sun goes down and it gets dark, your body’s levels of the sleep-inducing hormone melatonin rise. This, coupled with the increase in adenosine in the brain, means you get tired and fall asleep.


In order for adenosine to work, it has to first bind to an adenosine receptor. This is often compared to a key fitting into a lock.


In this analogy, adenosine is the key and when it finds the right lock it slides in and delivers the message: brain slow down, person be sleepy. (It’s a well-known scientific fact that neuromodulators talk like cavemen).


But what if something else has already gone into the lock? In that case, the adenosine can’t get in and deliver the message to the brain to slow down and be drowsy.


That, gentle reader, is what the caffeine molecule does.


Caffeine is a competitive adenosine receptor antagonist. This means it blocks adenosine by inserting itself into the adenosine lock, but it doesn’t deliver the same signal to the brain to slow down.


When you wake up in the morning, your levels of adenosine are relatively low, but these low levels still need to be cleared. If you have caffeine immediately upon waking, fewer receptors will be available for the adenosine to bind to, so it will remain at that level while the caffeine remains in your system.


When the caffeine wears off and the receptor sites once again become available, the adenosine can slot in, delivering its message to your brain. This is thought to be the mechanism behind the mid-morning slump that may cause you to reach for that second cup of coffee.


Hindsight being 20:20 I should not have used the word “inevitably” – I should have used much milder language like “could possibly lead to” or “will likely lead to a mid-morning slump.”


However, the post wasn’t only about the potential of coffee first thing in the morning to lead to a mid-morning slump and I maintain that it’s a habit you might want to consider changing.


Here I will say (again) that I’m not saying you shouldn’t drink coffee AT ALL. I’m just saying you might want to consider experimenting with the time you consume it.


Click here to check out Dr Andrew Huberman (tenured professor in the Department of Neurobiology at Stanford University School of Medicine) talk about the interaction between adenosine and caffeine in Episode #2 of the Huberman Lab Podcast.



Coffee first thing in the morning can really mess with your hormones – not just your sex hormones but your stress response hormones as well:


Please note that I didn’t say it WILL, I said it CAN. And for a lot of people (like, a lot of people) it DOES.


Caffeine causes the pituitary gland to secrete hormones that stimulate the adrenal glands to produce adrenaline and cortisol.


Adrenaline is part of your body’s sympathetic nervous system response and is your main “fight or flight” hormone. According to the education resource You and Your Hormones from the Society for Endocrinology, adrenaline is responsible for raising your heart rate, increasing blood pressure, expanding the air passages of the lungs and changing the body’s metabolism to maximise blood glucose levels.


This is part of the reason why you feel more alert, have better attention and a burst of energy after coffee. In plain speech, it jacks you up because your body is preparing to react in case shit gets real.


If that’s the way you want to start your day, by slamming your hand down on your body’s innate panic button, then that’s entirely up to you. The problem is that a lot of people are dealing with problems of elevated stress and anxiety in their lives without being aware of the contribution that drinking coffee first thing in the morning is having on this issue.


Next, we have cortisol. Cortisol is commonly referred to as a “stress hormone” but it’s actually the primary hormone secreted by your adrenal gland that signals the body to be awake and responsive. Cortisol rises and falls during the day according to circadian rhythm. Levels of cortisol are highest in the morning, peaking around 8:30am, and lowest around midnight.


Studies show that consuming caffeine when cortisol is high can push your body to produce more cortisol and while the exact mechanism isn’t clearly understood, it might have something to do with the impact coffee has on certain vitamins and minerals (like water soluble B vitamins that incidentally are essential to women’s hormonal health, discussed further below).


Elevated levels of cortisol also interfere with our ability to regulate inflammation and blunt our immune response.



You Mentioned Sex Hormones?


I did. It caused at least one person to LOL at me in the comments. Probably because I said sex.


For those with female sex hormones (aka reproductive hormones) caffeine first thing on an empty stomach can potentially interfere with your hormonal cascade because of its ability to disrupt your blood sugar.


A recent study in the British Journal of Nutrition found that participants who had coffee before eating suffered impaired blood sugar control.


In an interview with SciTechDaily Professor James Betts, co-director of the centre where the study was conducted said:


“We know that nearly half of us will wake in the morning and, before doing anything else, drink coffee – intuitively the more tired we feel, the stronger the coffee. This study is important and has far-reaching health implications as up until now we have had limited knowledge about what this is doing to our bodies, in particular for our metabolic and blood sugar control.


Put simply, our blood sugar control is impaired when the first thing our bodies come into contact with is coffee especially after a night of disrupted sleep. We might improve this by eating first and then drinking coffee later if we feel we still need it. Knowing this can have important health benefits for us all.”


According to hormone health expert and functional nutritionist Alisa Vitti, this is important in the context of female reproductive hormones because spikes in blood sugar are accompanied by spikes in insulin, which in turn can have an effect on ovulation and disrupt the important balance between estrogen and progesterone.


Alisa believes that women shouldn’t drink coffee at all, and you can read about her reasons for this recommendation here.


As for me, I’m not saying that all women should quit coffee. I’m just saying that it’s not the best thing to have it as soon as you wake up, on an empty stomach.



Chinese medicine considers coffee hot and drying:


Yes, it does.


Chinese medicine dietary therapy doesn’t just classify food according to its nutritional profile, it also considers the energetics of the food. Does the food warm or cool the body? Does it moisten it or dry it? Does it have an astringing or dispersing action?


Foods are grouped into five flavour categories: bitter, spicy, pungent, sweet or bland. And each of the flavours corresponds to an organ.


As I said in my caption, the stomach is acidic. In fact, the parietal cells of your stomach secrete hydrochloric acid.


Hydrochloric acid is highly corrosive (it can eat through metal). The stomach has a pH of 1.5 – 3.5. If hydrochloric acid came in contact with your skin it would immediately begin to dissolve it. Your stomach lining (gastric mucosal barrier) is what keeps this hydrochloric acid contained.


In his book on the topic of dietary teachings from classical Chinese medicine (“Welcoming Food Book 1: Energetics of Food and Healing”) Andrew Sterman explains it as follows:


“The stomach is the body’s hub of hydration. For healthy digestion, eating moist foods is even more important than drinking enough water. From the stomach’s point of view, the wet foods we eat are time-release doses of hydration. The stomach loves stews, soups, porridges, and steamed grains. Moist foods also support the protective stomach lining. A good diet regulates (balance) stomach yang (the acids which stoke appetite and digest food) and stomach yin (the lining which protects the stomach from its own acids). Making certain that we eat moist foods is absolutely central to our health.”


And even if you think Chinese medicine is bullshit, modern research shows us that coffee can increase the production of stomach acid. It’s not exactly a huge intellectual leap to make the connection that over time, the habit of increasing the acidity of your stomach first thing in the morning could lead to digestive issues.


So, there you have it. This is the information on which I based the statements in my Instagram post. It’s hardly exhaustive but I hope it helps to provide context for the suggestion I made.


To close I will say what I said to my husband earlier:


“It's weird that some people are getting so worked up about it – it’s not like anyone has to do what I say!”


His response: “No one except me anyway.”


Too true Darling, too true.



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