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Hey team, Mikki here. You are tuning in to Mini Mikkipedia Monday and today I want to talk about coffee. To be fair, if I was to cover the entire literature base for benefits, the risks, anything else in between, it would probably take me hours. So I'm just choosing a couple of things to broadly discuss today and could probably dive deeper into a topic.

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on another mini-Mikkipedia. Anyway, coffee, you either love it or you hate it. The black elixir, which has antioxidant properties and a distinctive smell and taste, and is now one of the world's most popular beverages. Sort of something like olives. Definitely grows on people over time. You know, there appears to be some sort of gradient whereby we start with drinking hot chocolate. We move to a moccaccino. Then it's a cappuccino.

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if you're like me, that was also a malatino. I used to go to a cafe called The Perculator in Dunedin. Great cafe, still there, still great. And order a malatino in a bowl, I'd get like eight marshmallows. And I would get two of them, because I'd probably just done about 90 minutes on the elliptical at the gym. Anyway, we moved on. Latte, flat white, long black. Then suddenly, it's a shot or three in one hit. And in fact, I still remember the first time at university,

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ordered a shot in a tiny little coffee cup. And I thought, wow, such a small cup, such a big guy. Anyway, even a lot of people who don't love the taste of coffee, love the smell. So it is estimated that over 2.25 billion cups of coffee are consumed every day. It makes coffee the second most traded commodity in the world after oil. Consumption continues to increase at about 2.5% a year.

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Europe, North America and Brazil are the top coffee-consuming countries. And there are regional differences as to where people consume their coffee, either at home, such as Asia, or in cafes, such as the US. Rapid growth of consumption has led to sustainability concerns however, as production can bring with it negative environmental impacts, such as soil erosion, water pollution and deforestation. However,

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coffee producers have put into place practices that help minimize the consequences of this. I have to say, when I read that, it did make me feel a lot better. So while coffee and alcohol often get lumped together in terms of their negative health consequences, that's super interesting because the documented health benefits of coffee far outweighs the harmful effects at the population level. Habitual coffee drinking is associated with improved cognitive function,

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including improved attention, alertness, and reaction time. And this is why it is classed as a neutropic, due to its effects on sensitizing neurons in the brain. It works by taking up space on the adenosine receptors in the brain, and adenosine is something which helps us relax. So when caffeine acts on the receptors, it blocks that adenosine, and in turn also influences the dopamine,

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serotonin, acetylcholine, and adrenaline systems. Studies in mice show that genetic variations in adenosine receptors can in fact confer neuroprotective effects of coffee, protecting the brain against oxidative stress and damage and potential subsequent disease. And like I said, it gets lumped in with alcohol, but the metabolic health impacts of coffee are actually pretty impressive too.

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at a population level, and there may well be, though, individual differences. So let me discuss what we see. Coffee does improve insulin sensitivity and reduces risk of type 2 diabetes in epidemiological research. However, in the acute setting, so in a controlled trial, when it's studied for its direct impact on blood sugar and insulin through a glucose challenge, there tends to be an increase in either glucose or insulin.

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And having coffee after a night of fragmented sleep, so you have a disrupted sleep, you have a very light sleep, you just don't get a great sleep. Having a coffee, which is something almost all of us coffee drinkers will do, and we often talk about how much we would do it and love it, it's actually worse for blood sugar control than just the disrupted sleep alone. So that's pretty interesting. And the reason for this apparent contradiction,

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between what the epidemiology shows and what we see in a controlled trial is a bit complex and it's not actually entirely understood. One possible explanation is the aforementioned impact that caffeine has on the release of hormones such as cortisol and adrenaline. This can increase blood sugar levels in the short term by stimulating the release of glucose from the liver. The conversion of glycogen, our stored carbohydrate, into glucose.

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and that also reduces glucose uptake into our muscle and fat cells. So it keeps glucose in the bloodstream for longer. Corazol can also block the effects of insulin, making it less effective at disposing of glucose. So this is in that controlled sort of clinical setting. Conversely, other studies have actually shown that caffeine may increase the uptake of glucose into muscle cells, which can help lower blood sugar levels over time.

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Caffeine has been shown to stimulate the production of a protein called glucagon-like peptide 1, or GLP-1, and this plays a role in regulating blood sugar and improving insulin sensitivity. When GLP-1 binds to its receptors on the beta cells of the pancreas, it triggers the release of insulin into the bloodstream. This helps to lower blood sugar levels by promoting the uptake of glucose into muscle and fat cells.

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GLP-1 can also slow down the rate at which food leaves the stomach, which can then help to prevent spikes in blood sugar levels after meals. It also reduces the production of glucagon, which is a hormone that raises blood sugar levels, and it promotes the growth and survival of the beta cells in the pancreas, which are responsible for producing insulin. So as I said, it's a complex sort of scenario here where you've got two contradicting

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bodies of research. What we can't ignore though is that on balance population studies show a positive relationship between caffeine or coffee and metabolic health in both normal and overweight individuals. And of course coffee isn't just the caffeine, it's got a number of antioxidants and polyphenols which may well be responsible for a lot of the health effects we see.

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In addition to the insulin sensitizing impact described above, there is research that suggests moderate consumption of coffee may reduce the risk of liver disease and prevent progression of liver disease and cirrhosis. And this is all types of coffee too. Instant, plunger, filter, decaffeinated coffee. So it's actually not the caffeine itself, it's potentially those polyphenols I was mentioning.

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I mentioned some of the neurological or neuroprotective benefits of caffeine earlier. There is research to show that coffee confers protection specifically against Parkinson's disease. And this is thought to be due to its ability to block the action of the adenosine A2A receptors in the brain that are involved in the development of the disease, minimizing neurotoxicity and neuroinflammation.

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neutral or decreased risk of cancer with coffee consumption actually. A review on the topic suggests that studies conducted lack the rigor required to make any definitive sort of statement on it. Given the fact that coffee has been consumed for basically ever, not unlike red meat really, it's unlikely that in of itself it is a carcinogen. How you have your coffee in all health conditions will likely be a bigger contributor to health risk or benefit.

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i.e. if your standard order is a Frappuccino and you've got some health concerns going on, gaining weight, visceral adipose tissue, and you've got other major lifestyle factors that aren't really in favor of health, like your sedentary, your overall diet quality's not great, I don't think that a Frappuccino coffee order is probably gonna work in your favor. But also, I don't think that any health risk associated with the scenario I described

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could probably be pinpointed on just coffee or caffeine alone. How we metabolize caffeine and its impact is related to our genes. And I did mention there are genetic differences in our adenosine receptors earlier. Specifically, the CYP1A2 gene is responsible for the production of an enzyme that breaks down caffeine in the liver.

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not just caffeine actually, a whole lot of toxins and medications and things like that. The activity of this enzyme can vary between individuals depending on their genetic makeup. Someone can seemingly drink coffee after dinner and sleep quite soundly. Others need to limit it to before 10 a.m. if they want a decent night's sleep. And this is largely thought to be due to how we metabolize caffeine. So understanding how genetics affect the coffee metabolism can be important for individuals.

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who want to optimize their coffee consumption. So the obvious example is that if you are more sensitive to caffeine, you might want to limit your intake, while those that metabolize caffeine quickly may be able to consume more without experiencing those negative side effects. And this is almost like self-selected groups because in my experience, and I'm sure you will sort of appreciate what I'm saying here is that if you don't feel good on coffee, you're probably not gonna drink it.

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Whereas if you have like four to five cups of coffee and actually feel fine, then that's probably telling you that you're quite a fast metabolizer. So I just find that super interesting. And I've talked a bit about the potential health benefits or known health benefits of coffee or caffeine. The obvious negative effects of coffee, which could largely be due to how we metabolize it, do include increased anxiety and insomnia.

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And this can change even for the individual, depending on other stresses. So for example, you might be able to handle three double flat wipes on holiday when you've got nothing else going on, you're super relaxed and you don't have to worry about the next email or the deadline, yet when you're up against it at work, and it's like, I don't know, March, you're still thinking about how awesome your summer holiday was, but now you've got 15 things that you have to do, that's when

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increased coffee consumption may be more likely, but also could be more detrimental to how it impacts you. And I certainly speak to people who have increased anxiety, have that tired and wired feeling, possibly have that disrupted blood sugar I was talking about earlier that is brought on by lack of sleep and coffee, and ultimately it doesn't bode well for them.

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on the central nervous system as a stimulant, as I mentioned earlier, with its impact on cortisol. And there are in fact three potential mechanisms of action. And I'm not going to go into them really just because the major sort of action which people think is responsible for its stimulating effect is the fact that it blocks adenosine on the adenosine receptors, as I've already mentioned, which in turn directly sort of affects the release of our neurotransmitters and prevents

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the depressant effects of adenosine. Other mechanisms of action involved sort of mobilization of intercellular calcium and preventing the breakdown of an enzyme cyclic adenosine 3,5-monophosphate, which when accumulates does increase the release of adrenaline and cortisol. However, in both of these sort of other scenarios or mechanisms of action, the amount of caffeine we have to consume for these to be major players.

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is in fact sort of headed into that toxic range apparently. So that really is its impact on those adenosine receptors, which is largely responsible for how we feel. Most recent study actually came out looking at caffeine consumption and in response to insufficient sleep. And it sort of reviewed what we understood about how caffeine might impair the onset and maintenance of subsequent sort of sleep cycles.

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I think this is really important for anyone that is in that cycle of not enough sleep for whatever reason and then relying on caffeine to get them through the next day to then go to bed tired and wired and unable to sleep again. And certainly personally right now, I have just gone through a few different time zones, have had a lot of other things sort of crop up with work and clients and stuff, which is awesome. But it certainly has meant that I've had many nights.

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where I hadn't got the sleep that I have wanted. And I've tried super hard to stay off the caffeine, but I've gotta be honest, it's not easy. However, a most recent review looked at caffeine consumption and found a reduced total sleep time, interestingly, by 45 minutes and sleep efficiency by 7%, with an increase in sleep onset latency of nine minutes and wake after sleep onset of 12 minutes.

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So basically, sleep efficiency is like quality of sleep, reducing our overall time by almost an hour. That three quarters of an hour is quite significant and takes us longer to fall asleep and stay asleep. Light sleep duration increased by six minutes and a deep sleep duration. So where all of that sort of recovery and restorative sort of function happens in deep sleep, that duration was reduced by 11 minutes.

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So some recommendations, to avoid reductions in total sleep time, coffee, about 107 milligrams per 250 mils, so it's about an espresso amount, or just over one shot, should be consumed at least 8.8 hours prior to bedtime. So that's, if you're off to bed at nine o'clock, you don't wanna be having coffee after 12. 150 milligrams is about the amount we find in a standard double shot.

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So especially if you're having problems with sleep quality or duration, you do want to stop having coffee after sort of midday. If you're like me and have been enjoying a pre-workout before hitting the gym, then the latest you should consume the standard dose of caffeine, which comes in at quite a whopping 217 milligrams, should be about 6 a.m. for that same 9 p.m. bedtime, because there is a 13 hour lag.

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Coffee has a half life of about six hours. So in six hours, you will have half the amount of caffeine that is in your system when you first have coffee. But again, everyone is different as to how they metabolize it. And I think this type of information is really important for people who do struggle with sleep. I speak to so many people who do not make the link between their 10 a.m. coffee and inability to sleep. Whereas it is a game changer once they

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take it out and I think this research just really quite highlights that potential impact. And what I will say is the best thing you can do if you experience the negative jittery impact of caffeine or the noticeable impact on sleep is to cut down or avoid it completely. Of course that does bring with it significant withdrawal effects for a lot of people so my best advice is to decide to quit on a Friday and then you've got

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Pretty rubbish day on Friday, but you've got Saturday and Sunday to recover from those flu-like symptoms and then hopefully by Monday, end of day Monday, that would have been resolved. It is short-term pain, but it will be for long-term gain because those symptoms can last three to four days. And the last thing that I will say about coffee and another interesting study that's come in is that it is known for its ability to increase free fatty acids circulating in the bloodstream.

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which can then be used for energy. It's a ketogenic substance which promotes fat burning and ketone production and has been studied for its usefulness in weight loss. There is some research to support the notion that caffeine alone can help. In a recent analysis of a large cohort of participants, analyzed coffee consumption in relation to fat loss and found that those who increased the amount that they drank each week, from less than three cups a month to one to seven per week,

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had a significant reduction in adipose tissue, including visceral adipose tissue. That's that inflammatory fat that builds up in and around our organs, and in trunk fat and overall body fat. And this was over a three year follow-up. This was a large cohort, close to 1,500 participants who were enrolled in a diet and exercise intervention. So it's certainly interesting. However, despite the changes being statistically significant,

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the actual numbers were relatively small and probably not overly meaningful, which is just food for thought or coffee for thought. Another study, just throwing another one out there, that gave adolescents either green tea with catechins and a caffeine equivalent to 96 milligrams or coffee equivalent to 160 milligrams, about a double shot. In addition to a nutrition intervention,

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found that those in the coffee arm had a greater reduction in body fat in the caffeine group. So there's research to support its use in fat loss. Caffeine does have an appetite suppressing effect, or coffee does. And certainly this is true of anyone. I don't need to probably convince anyone who has had a period of fasting whereby they might feel a little bit hungry, they have their black coffee, and that suppresses their appetite.

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can reduce overall calorie intake regardless of any sort of mechanism whereby fat burning is increased and therefore fat loss is increased. Because actually fat burning doesn't relate to a fat loss increase. Those are two quite separate mechanisms occurring. So anyway, coffee, just a little bit of information for you. Hopefully you enjoyed that. And I look forward to catching you on the next.

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Mini Micopedia. If there is any topic that you would like me to cover or you're super interested in, just let me know. See you later.