Original paper Works also with tea ! Ideal dose according to the study: They seems to have adjusted the effect (i.e. reduce effect such as "rich people drink more coffee, but since they're rich...
Higher intake of tea showed similar associations with these cognitive outcomes, [...]
Ideal dose according to the study:
The most pronounced associated differences were observed with intake of approximately 2 to 3 cups per day of caffeinated coffee or 1 to 2 cups per day of tea.
They seems to have adjusted the effect (i.e. reduce effect such as "rich people drink more coffee, but since they're rich they have better access to medecine"), but it's not detailled in the abstract.
After adjusting for potential confounders and pooling results across cohorts, [ ...]
I was surprised at the distinction between 2-3 cups of coffee and 1-2 cups of tea, since tea typically has less caffeine than coffee. This might be the way of how they binned amount of coffee...
I was surprised at the distinction between 2-3 cups of coffee and 1-2 cups of tea, since tea typically has less caffeine than coffee. This might be the way of how they binned amount of coffee drinking, or I wonder if there are other plant compounds present in tea that promote a synergistic effect.
From cursory research, it seems that while caffeine by dry weight may be higher in tea than roasted coffee beans, the caffeine per cup of drink is almost always lower in tea due to amount used and...
From cursory research, it seems that while caffeine by dry weight may be higher in tea than roasted coffee beans, the caffeine per cup of drink is almost always lower in tea due to amount used and strength of the extraction. Around 30-70mg for 8oz of tea versus 90-120mg for coffee. Also caffeine varies with part of the tea plant you're using, more for whole leaves and less for the stems and dust in cheap bags that most people drink daily.
Then you have the "kopi" in southeast asia that use 100% robusto beans and average 100-200mg, sometimes upwards of 265mg, in an 8oz cup (plus a bunch of condensed milk and white sugar). The majority of people drink one or more cups of this rocket fuel coffee daily.
Yeah, and it's one of these difficult things where you really have to consider the dose of tea or coffee being used, the quality of the tea / loose leaf vs bag, the type of tea or coffee, how...
Yeah, and it's one of these difficult things where you really have to consider the dose of tea or coffee being used, the quality of the tea / loose leaf vs bag, the type of tea or coffee, how they're brewed/extracted, etc because things can vary widely. (I can brew up a pot of some raw pu'erh tea that will knock my socks completely off)
The video is not out yet, but Lance Hedrick did some caffeine testing doing a coffee brew on an OXO Rapid Brewer vs a Pourover, and the results he has hinted at in a live video so far put the pourover as quite a bit higher in caffeine strength, despite using the same amount of coffee for each brew. So just the extraction method alone can make a big difference (don't quote me on this as no official results have been published yet though)
It can be a little messy to nail down the most "typical" use but I'd say that's generally true just based on a (made at home in a coffee pot, not cafe) very generic "8oz of brewed regular (Arabica) coffee using typical coffee dose/strength" and "8oz of brewed (black) tea using a standard tea bag like Lipton". For that you're looking at something, very generalizing here, of like ~100-120mg for the coffee and ~50-70mg for the tea.
A single shot of espresso will be about the same as the tea, maybe averaging slightly on the higher end. But then again, let me reiterate how difficult it is to nail down specific figures- because if you look at Starbucks' Pike Place Roast, their 8oz cup of black coffee is 155 mg - 195 mg (stated directly on their site), when purchased in prepared form from their cafe, which is quite a bit more than one would expect for a coffee that size.
But this all got off on a bit of a tangent- but yeah, in general, for very typical mass produced consumer tea consumption of a black Lipton tea bag, that's 55mg for the tea, compared to 2x that for a coffee of the same size brewed at a typical strength
Quite interesting. I actually was really looking into this in Jan-Mar of 2020, just before covid hit, as I was trying to figure which had the most. None of my info was about dry anything - that...
From cursory research, it seems that while caffeine by dry weight may be higher in tea than roasted coffee beans, the caffeine per cup of drink is almost always lower in tea due to amount used and strength of the extraction. Around 30-70mg for 8oz of tea versus 90-120mg for coffee.
Quite interesting. I actually was really looking into this in Jan-Mar of 2020, just before covid hit, as I was trying to figure which had the most. None of my info was about dry anything - that really wouldn't matter to me because I wasn't using anything dry.
I know for a fact (and I have crap for memory, but I actually put it in a spreadsheet on my work laptop, as I had a lot of downtime and was being given bs intern-esque assignments) that teas generally had higher caffeine content simply because of the steeping time, whereas coffee could hit those numbers. What I remember is that coffee could surpass with some espresso roasts (and I'm not 100% sure on that data, it's been a while), the crazy-high caffeine bean types, and french pressing. But at the time I used a prepackaged bag of ground coffee and/or keurig-type drink maker, which also doubled for the teas I consumed. So the pods I believe typically gave more caffeine for coffee than tea, though ... honestly, I don't remember, and yes, I spent that much time working figuring this stuff out bwahaha.
But yeah, I am speaking as a generic American who is likely atypical simply because I drink both coffee and tea.
You keep saying tea has higher caffeine because it has "higher steeping time", but most coffee isn't brewed through "steeping". In the coffee world the term you'd use for "steeping" would be...
You keep saying tea has higher caffeine because it has "higher steeping time", but most coffee isn't brewed through "steeping". In the coffee world the term you'd use for "steeping" would be "immersion brewing", and immersion brewing is things like French Press. But most other common brewing methods don't use immersion, but instead percolation (pour over and traditional drip coffee both are percolation brews), or it uses them togetherin some combination. Percolation brewing involves forcing water through the coffee and a filter but constantly uses new clean water rather than remaining all in the same slurry, and most relevantly, percolation brews allow you to extract more (and for the coffee nerds, different) compounds from the same amount of coffee and to do so more quickly. Percolation brews can also vary in speed, which of course influences their extraction, but the fact that they're not "steeping" means that linearly comparing "steep time" makes no sense with percolation brews. It makes even less sense once you advance to brewing methods like the Moka Pot or espresso, which use pressure to force water through coffee in a way that extracts even more into a smaller amount of water in a relatively short amount of time. Of course, whether you consider a shot of espresso to have more caffeine than a cup of tea depends on whether you're comparing caffeine by volume or the total amount regardless of volume. Both are valid for their own reasons, but which you choose would drastically affect the comparison.
I'm not familiar with any source that claims that brewed tea has more caffeine than brewed coffee for any reason prior to reading your comment, and if you have the source where you learned your information, I'd be interested in it. That said, I would not trust any source that claimed it was due to "longer steep times" to have accurate information on this, as it would demonstrate a real lack of familiarity with coffee brewing whatsoever. Even if only comparing tea steeping to immersion brewing, "longer steep times" would need to be accompanied by an explanation of why the increased steep times don't instead indicate that it is more difficult to extract the relevant compounds from tea than from coffee, especially given that the number of grams per liter of water used for tea is drastically lower than for coffee brewing. And there are differences even among teas when it comes to the details on the desired time and temperature of water to be used, after all, and it cannot be taken for granted that coffee and tea may have quite different properties in that respect as well.
No, coffee typically percolates, as you mention. And I've now re-read up on the internet, and I'm wrong. I [mistakenly] thought stronger teas (black) could reach around 80 mg, but this is not what...
No, coffee typically percolates, as you mention. And I've now re-read up on the internet, and I'm wrong. I [mistakenly] thought stronger teas (black) could reach around 80 mg, but this is not what I'm seeing now... the caffeine I am drinking is not protecting my brain enough apparently. :)
And, I typically was thinking that time was the key effect - so while coffee typically can produce more caffeine, stronger caffeinated teas could compete. I do not see data for this now, so there's that.
Thanks for sharing. I posted this to the ~science group and did my due diligence there, but the taggers (thank you for your work) moved it to this group. I guess I should've just searched across...
Thanks for sharing. I posted this to the ~science group and did my due diligence there, but the taggers (thank you for your work) moved it to this group. I guess I should've just searched across the site and not a specific group.
Ah no worries! And thank you for checking first, it's nbd to repost -- there's a different energy to the comments this time, and I think it's a different study, too.
Ah no worries! And thank you for checking first, it's nbd to repost -- there's a different energy to the comments this time, and I think it's a different study, too.
I drink lots of quality coffee and tea, so, nice! I always take these things with a big grain of salt but always feels nice when you think some of your simple habits might be having a positive effect
I drink lots of quality coffee and tea, so, nice! I always take these things with a big grain of salt but always feels nice when you think some of your simple habits might be having a positive effect
I think that is the best way to do it. 18% isn't mathematically significant enough to change habits in my opinion. It's still important to know, especially for someone who may be genetically...
I think that is the best way to do it. 18% isn't mathematically significant enough to change habits in my opinion. It's still important to know, especially for someone who may be genetically predisposed or worried about future dementia.
Your morning coffee or tea could be quietly supporting your brain health. A long-term study found that moderate consumption of caffeinated coffee or tea was linked to an 18% lower risk of dementia and better cognitive performance over time. The benefits appeared strongest at 2–3 cups of coffee or 1–2 cups of tea daily—and even held true for people genetically predisposed to dementia.
Yeah I had the exact same thought. I'm wondering if it might be a survey artifact or if there is some sort of synergistic effect with compounds in tea leaves.
Yeah I had the exact same thought. I'm wondering if it might be a survey artifact or if there is some sort of synergistic effect with compounds in tea leaves.
[...] Furthermore, tea components such as epigallocatechin-3-gallate and L-theanine may provide additional benefits by enhancing relaxation and neuroprotection.
Looking at my pre-workout... probably not LOL. You've seen the way I talk about card games, I probably have some type of short term memory issue (not really but ya know)
Looking at my pre-workout... probably not LOL. You've seen the way I talk about card games, I probably have some type of short term memory issue (not really but ya know)
Disclosure: I like coffee and feel vindicated by these findings. This a pretty small effect size, but from the studies I've read it seems like caffeine is leaning more towards the bin of "good for...
Disclosure: I like coffee and feel vindicated by these findings. This a pretty small effect size, but from the studies I've read it seems like caffeine is leaning more towards the bin of "good for us".
Food for thought: let's say that there was a discovery that showed a given food or drink was unequivocally good for your health, especially as it pertains to healthy aging, but you hated the taste of it. Would you make any effort to try and "acquire" a taste, or just say screw it and take your chances with your current diet/approach?
Interesting question! For me it would come down to exactly how beneficial the food was, how much I disliked it, and what else I was already doing for my health. Personally, I've already found a...
Interesting question! For me it would come down to exactly how beneficial the food was, how much I disliked it, and what else I was already doing for my health. Personally, I've already found a decent balance of things I enjoy and things that are good for me. I wouldn't try too hard to incorporate something I didn't enjoy unless it had serious, undeniable benefits.
I spent a decade working with seniors and saw first hand how important a good diet is to aging well. Physical activity, socialization, and staying engaged mentally all play a part and can't be ignored. I'd sooner join a book club, walk laps of the local mall, or do a crossword puzzle every day than try to shoehorn another miracle food into my diet.
I'd probably try to work it in to tacobell-adjacent tacos. Or a smoothie of some sort. Or worst case as capsules of dehydrated food. And I think we have some foods like that: Basically any leafy...
I'd probably try to work it in to tacobell-adjacent tacos. Or a smoothie of some sort. Or worst case as capsules of dehydrated food.
And I think we have some foods like that: Basically any leafy green that isn't iceberg lettuce.
Personally, unless that specific food/drink was significantly better (really significant, say, reduces risk of cardiovascular disease by 90%) for my health, I wouldn't bother In my particular...
Personally, unless that specific food/drink was significantly better (really significant, say, reduces risk of cardiovascular disease by 90%) for my health, I wouldn't bother
In my particular case, there is not a single food (or combination of foods) on Earth that's going to reduce my risk of lifetime cancer (again) to a degree which is significant enough to offset the risk I'm currently exposed to, so I wouldn't even try on that front.
I still exercise, socialise, avoid unhealthy foods in large quantities and study new topics as those fall inside the category of having a significant, measurable and unequivocal short/long term effect, but "superfoods" feel like a drop in a very large bucket.
Conversely, there isn't anything I can definitely say I hate the taste of (except fish), so I'd be willing to give everything else a try
My guess is this is largely caused by increased blood flow to the brain from caffeine. Would be interesting to see a comparison with people just just took caffeine pills.
My guess is this is largely caused by increased blood flow to the brain from caffeine. Would be interesting to see a comparison with people just just took caffeine pills.
Here's the paragraph of the study talking about potential mechanisms:
Here's the paragraph of the study talking about potential mechanisms:
The neuroprotective effects of caffeine are supported by multiple potential mechanisms. Caffeine, primarily through its antagonism of adenosine A1 and A2A receptors, modulates synaptic transmission and attenuates Aβ accumulation. Experimental studies have shown that caffeine lowers Aβ levels, suppresses β- and γ-secretase activity, enhances neuronal plasticity, and stimulates mitochondrial function and prosurvival signaling pathways. In addition, caffeine may lower brain proinflammatory cytokines and mitigate neuroinflammation, which are key contributors to cognitive decline and the development of AD. The ability of caffeine to improve insulin sensitivity and reduce the risk of type 2 diabetes, which is a major risk factor for dementia, further contributes to its protective effect on cognitive health. Beyond caffeine, coffee and tea contain bioactive compounds like polyphenols, chlorogenic acid, and catechins, which offer antioxidant and vascular benefits by reducing oxidative stress and improving cerebrovascular function. Furthermore, tea components such as epigallocatechin-3-gallate and L-theanine may provide additional benefits by enhancing relaxation and neuroprotection.
Caffeine is a vasoconstrictor, so if anything it reduces blood flow to the brain. I wonder if that reduced flow could somehow have a positive impact on this type of thing?
Caffeine is a vasoconstrictor, so if anything it reduces blood flow to the brain. I wonder if that reduced flow could somehow have a positive impact on this type of thing?
Not totally out there! Ibuprofen also constricts blood vessels and there has been a link between chronic, low-dosage use and decreased risk for Alzheimer's. Also not a very strong effect if I...
Not totally out there! Ibuprofen also constricts blood vessels and there has been a link between chronic, low-dosage use and decreased risk for Alzheimer's. Also not a very strong effect if I remember correctly.
So caffeine on it's own is a vasoconstrictor and thus reduces blood flow to the brain, but I was doing some reading and found this study supporting your hypothesis but kind of in the opposite...
So caffeine on it's own is a vasoconstrictor and thus reduces blood flow to the brain, but I was doing some reading and found this study supporting your hypothesis but kind of in the opposite direction whereas when chronic caffeine consumers don't have any caffeine in their system they actually have increased blood flow to the brain - so maybe?
Great! I was going to keep drinking 2-3 cups of coffee a day regardless because it's delicious, but glad it's good.
Yea, unless its full "cigarettes cause lung cancer" bad, I don't forsee myself changing my habits. Even then....
Original paper
Works also with tea !
Ideal dose according to the study:
They seems to have adjusted the effect (i.e. reduce effect such as "rich people drink more coffee, but since they're rich they have better access to medecine"), but it's not detailled in the abstract.
I was surprised at the distinction between 2-3 cups of coffee and 1-2 cups of tea, since tea typically has less caffeine than coffee. This might be the way of how they binned amount of coffee drinking, or I wonder if there are other plant compounds present in tea that promote a synergistic effect.
I thought tea had more typically (also varies with type) than brewed coffee, though french-pressing coffee typically ramps up the steeping time.
From cursory research, it seems that while caffeine by dry weight may be higher in tea than roasted coffee beans, the caffeine per cup of drink is almost always lower in tea due to amount used and strength of the extraction. Around 30-70mg for 8oz of tea versus 90-120mg for coffee. Also caffeine varies with part of the tea plant you're using, more for whole leaves and less for the stems and dust in cheap bags that most people drink daily.
Then you have the "kopi" in southeast asia that use 100% robusto beans and average 100-200mg, sometimes upwards of 265mg, in an 8oz cup (plus a bunch of condensed milk and white sugar). The majority of people drink one or more cups of this
rocket fuelcoffee daily.Yeah, but I'm talking about more typical usages. Just an espresso or cuppa vs tea, not a Monster-esque bomb.
I can't speak for espresso, but drip coffee typically has more caffeine than tea.
Yeah, and it's one of these difficult things where you really have to consider the dose of tea or coffee being used, the quality of the tea / loose leaf vs bag, the type of tea or coffee, how they're brewed/extracted, etc because things can vary widely. (I can brew up a pot of some raw pu'erh tea that will knock my socks completely off)
The video is not out yet, but Lance Hedrick did some caffeine testing doing a coffee brew on an OXO Rapid Brewer vs a Pourover, and the results he has hinted at in a live video so far put the pourover as quite a bit higher in caffeine strength, despite using the same amount of coffee for each brew. So just the extraction method alone can make a big difference (don't quote me on this as no official results have been published yet though)
It can be a little messy to nail down the most "typical" use but I'd say that's generally true just based on a (made at home in a coffee pot, not cafe) very generic "8oz of brewed regular (Arabica) coffee using typical coffee dose/strength" and "8oz of brewed (black) tea using a standard tea bag like Lipton". For that you're looking at something, very generalizing here, of like ~100-120mg for the coffee and ~50-70mg for the tea.
A single shot of espresso will be about the same as the tea, maybe averaging slightly on the higher end. But then again, let me reiterate how difficult it is to nail down specific figures- because if you look at Starbucks' Pike Place Roast, their 8oz cup of black coffee is 155 mg - 195 mg (stated directly on their site), when purchased in prepared form from their cafe, which is quite a bit more than one would expect for a coffee that size.
But this all got off on a bit of a tangent- but yeah, in general, for very typical mass produced consumer tea consumption of a black Lipton tea bag, that's 55mg for the tea, compared to 2x that for a coffee of the same size brewed at a typical strength
Quite interesting. I actually was really looking into this in Jan-Mar of 2020, just before covid hit, as I was trying to figure which had the most. None of my info was about dry anything - that really wouldn't matter to me because I wasn't using anything dry.
I know for a fact (and I have crap for memory, but I actually put it in a spreadsheet on my work laptop, as I had a lot of downtime and was being given bs intern-esque assignments) that teas generally had higher caffeine content simply because of the steeping time, whereas coffee could hit those numbers. What I remember is that coffee could surpass with some espresso roasts (and I'm not 100% sure on that data, it's been a while), the crazy-high caffeine bean types, and french pressing. But at the time I used a prepackaged bag of ground coffee and/or keurig-type drink maker, which also doubled for the teas I consumed. So the pods I believe typically gave more caffeine for coffee than tea, though ... honestly, I don't remember, and yes, I spent that much time working figuring this stuff out bwahaha.
But yeah, I am speaking as a generic American who is likely atypical simply because I drink both coffee and tea.
You keep saying tea has higher caffeine because it has "higher steeping time", but most coffee isn't brewed through "steeping". In the coffee world the term you'd use for "steeping" would be "immersion brewing", and immersion brewing is things like French Press. But most other common brewing methods don't use immersion, but instead percolation (pour over and traditional drip coffee both are percolation brews), or it uses them togetherin some combination. Percolation brewing involves forcing water through the coffee and a filter but constantly uses new clean water rather than remaining all in the same slurry, and most relevantly, percolation brews allow you to extract more (and for the coffee nerds, different) compounds from the same amount of coffee and to do so more quickly. Percolation brews can also vary in speed, which of course influences their extraction, but the fact that they're not "steeping" means that linearly comparing "steep time" makes no sense with percolation brews. It makes even less sense once you advance to brewing methods like the Moka Pot or espresso, which use pressure to force water through coffee in a way that extracts even more into a smaller amount of water in a relatively short amount of time. Of course, whether you consider a shot of espresso to have more caffeine than a cup of tea depends on whether you're comparing caffeine by volume or the total amount regardless of volume. Both are valid for their own reasons, but which you choose would drastically affect the comparison.
I'm not familiar with any source that claims that brewed tea has more caffeine than brewed coffee for any reason prior to reading your comment, and if you have the source where you learned your information, I'd be interested in it. That said, I would not trust any source that claimed it was due to "longer steep times" to have accurate information on this, as it would demonstrate a real lack of familiarity with coffee brewing whatsoever. Even if only comparing tea steeping to immersion brewing, "longer steep times" would need to be accompanied by an explanation of why the increased steep times don't instead indicate that it is more difficult to extract the relevant compounds from tea than from coffee, especially given that the number of grams per liter of water used for tea is drastically lower than for coffee brewing. And there are differences even among teas when it comes to the details on the desired time and temperature of water to be used, after all, and it cannot be taken for granted that coffee and tea may have quite different properties in that respect as well.
No, coffee typically percolates, as you mention. And I've now re-read up on the internet, and I'm wrong. I [mistakenly] thought stronger teas (black) could reach around 80 mg, but this is not what I'm seeing now... the caffeine I am drinking is not protecting my brain enough apparently. :)
And, I typically was thinking that time was the key effect - so while coffee typically can produce more caffeine, stronger caffeinated teas could compete. I do not see data for this now, so there's that.
deleted so I don't have to hear testicle jokes.
I don't play CoD, so I don't teabag. Sorry.
Um ok.
I'm on 3-4 cups, so we're good. I need it to calculate hyperspace coordinates, anyway.
(a similar study came up a month ago and spurred some debate)
Thanks for sharing. I posted this to the ~science group and did my due diligence there, but the taggers (thank you for your work) moved it to this group. I guess I should've just searched across the site and not a specific group.
Ah no worries! And thank you for checking first, it's nbd to repost -- there's a different energy to the comments this time, and I think it's a different study, too.
It wasn't a "similar study", it was the exact same one
Ah ... apologies.
I drink lots of quality coffee and tea, so, nice! I always take these things with a big grain of salt but always feels nice when you think some of your simple habits might be having a positive effect
I think that is the best way to do it. 18% isn't mathematically significant enough to change habits in my opinion. It's still important to know, especially for someone who may be genetically predisposed or worried about future dementia.
Article summary:
It’s interesting that the optimum amount is higher for coffee than tea, even though coffee has more caffeine per cup.
Yeah I had the exact same thought. I'm wondering if it might be a survey artifact or if there is some sort of synergistic effect with compounds in tea leaves.
From the study:
And maybe have a little more fun
https://www.nih.gov/news-events/nih-research-matters/viagra-associated-reduced-risk-alzheimers-disease
with a family history of dementia/alzheimers maybe I should start drinking coffee...
It certainly seems like it wouldn't hurt unless you have crazy hypertension (like me whoops!) or if you have caffeine sensitivity syndrome.
Looking at my pre-workout... probably not LOL. You've seen the way I talk about card games, I probably have some type of short term memory issue (not really but ya know)
Disclosure: I like coffee and feel vindicated by these findings. This a pretty small effect size, but from the studies I've read it seems like caffeine is leaning more towards the bin of "good for us".
Food for thought: let's say that there was a discovery that showed a given food or drink was unequivocally good for your health, especially as it pertains to healthy aging, but you hated the taste of it. Would you make any effort to try and "acquire" a taste, or just say screw it and take your chances with your current diet/approach?
Interesting question! For me it would come down to exactly how beneficial the food was, how much I disliked it, and what else I was already doing for my health. Personally, I've already found a decent balance of things I enjoy and things that are good for me. I wouldn't try too hard to incorporate something I didn't enjoy unless it had serious, undeniable benefits.
I spent a decade working with seniors and saw first hand how important a good diet is to aging well. Physical activity, socialization, and staying engaged mentally all play a part and can't be ignored. I'd sooner join a book club, walk laps of the local mall, or do a crossword puzzle every day than try to shoehorn another miracle food into my diet.
I'd probably try to work it in to tacobell-adjacent tacos. Or a smoothie of some sort. Or worst case as capsules of dehydrated food.
And I think we have some foods like that: Basically any leafy green that isn't iceberg lettuce.
Personally, unless that specific food/drink was significantly better (really significant, say, reduces risk of cardiovascular disease by 90%) for my health, I wouldn't bother
In my particular case, there is not a single food (or combination of foods) on Earth that's going to reduce my risk of lifetime cancer (again) to a degree which is significant enough to offset the risk I'm currently exposed to, so I wouldn't even try on that front.
I still exercise, socialise, avoid unhealthy foods in large quantities and study new topics as those fall inside the category of having a significant, measurable and unequivocal short/long term effect, but "superfoods" feel like a drop in a very large bucket.
Conversely, there isn't anything I can definitely say I hate the taste of (except fish), so I'd be willing to give everything else a try
My guess is this is largely caused by increased blood flow to the brain from caffeine. Would be interesting to see a comparison with people just just took caffeine pills.
Here's the paragraph of the study talking about potential mechanisms:
Caffeine is a vasoconstrictor, so if anything it reduces blood flow to the brain. I wonder if that reduced flow could somehow have a positive impact on this type of thing?
Not totally out there! Ibuprofen also constricts blood vessels and there has been a link between chronic, low-dosage use and decreased risk for Alzheimer's. Also not a very strong effect if I remember correctly.
So caffeine on it's own is a vasoconstrictor and thus reduces blood flow to the brain, but I was doing some reading and found this study supporting your hypothesis but kind of in the opposite direction whereas when chronic caffeine consumers don't have any caffeine in their system they actually have increased blood flow to the brain - so maybe?