Ben Greenfield reacts to a viral MRI example claiming a ~40% reduction in cerebral blood flow after a single caffeinated drink. He contextualizes that finding by noting MRI is a visualization tool but emphasizing many individual factors matter (genetics, health history, coffee quality). He explains genetic variation in caffeine metabolism—naming CYP1A2 (AA = fast metabolizer; AC/CC = slow metabolizers), mentions ADORA2A and COMT variants—and links genotype to differing risks and benefits (fast metabolizers may see cognitive benefits and reduced neurodegenerative disease risk with moderate intake; slow metabolizers face higher cardiovascular risk). He summarizes coffee’s pros (polyphenols, antioxidants, increased fat mobilization, endurance, gut motility) and cons (vasoconstriction, potential to worsen hypertension/arrhythmia), and recommends genetic testing and attention to coffee sourcing and personal health when deciding intake.
All right, it is reaction video time. Somebody just sent me this bad boy. I'm kind of nervous because it looks like somebody's mad at coffee.
Let's see where I underwent two MRI brain scans. This first scan with no caffeine in my system. Then I down just one drink. Now my second mri. This was my brain before caffeine. That looks bad was after. The difference between was remarkable.
It's like a 40% drop in the blood flow to your brain. So that's a lot.
So before caffeine, with caffeine, the blood flow to my brain dropped down 40%.
40%. 40%.
Really?
She said it, he said it, they both said it. So it must be 40% I was actually familiar with. This is an old study. I'm surprised this is just now making the circulations on social media all of a sudden. Again, MRI is just a way to visualize the brain. It's a pretty accurate way to visualize the brain. And. And it doesn't surprise me what they reported. Right. Constriction of blood vessels to the brain. And that scares a lot of people who are habitual caffeine or coffee users, because cutting off blood flow to the brain could cause some potential issues. But there's a lot more to the story than this because we have no clue. This woman's genetics, her health history, the type of coffee she was drinking, how she was metabolizing the coffee. I don't think it's any secret out there that the health benefits of coffee have been championed. For example, certain people who have a certain gene. This is important. I'll get more into this gene in a second. It's called the CYP1A2AA genotype. In those people, coffee can enhance cognitive function and focus and mental alertness. It means you're a fast caffeine metabolizer. Basically, that CYP1A2 gene, in people who have that genotype, they actually respond quite favorably to coffee. And in fact, moderate coffee intake of 1 to 3 cups day per per day has been associated with a reduced risk of neurodegenerative diseases like Parkinson's and Alzheimer's, largely due to its antioxidant properties. That's not something that people who don't have that genotype frequently see. But people who do have that genotype that allows them to metabolize coffee quickly, it's not as much of an issue. Coffee is also, of course, rich in polyphenols and in antioxidants, very similar to green tea that can lower the risk of chronic disease. Like type 2 diabetes, certain cancers, caffeine stimulates adrenaline production. Now this is important. Caffeine, same thing for nicotine, for example, is a vasoconstrictive agent. That's because of what it does to cortisol and adrenaline, which then cause the vasoconstrictive effect. It also though can mobilize fatty acids for energy, increasing how much fat that you burn, it increases endurance, right? It helps to decrease your rating of perceived exertion during exercise. For those of us who like to have a cup of coffee before our morning poop, we know it supports gut motility. It's even been shown to promote the growth of beneficial gut bacteria, which can be helpful for individuals who want to support their digestive system. And coffee has a lot of good things going for it. Now here's where. If you were to go into an MRI brain scan and you were to see super scary effects like 40% loss of blood flow to the brain, this is why something like that might happen to you or other reasons that coffee might not be a good idea or at least should only be consumed in moderation. You remember that CYP1 gene I mentioned, the double A genotype? Well, people who have the AC or the CC genotype, those are slow caffeine metabolizers. It lingers in the system. And those people do not experience the same cardiovascular benefits as people who are fast caffeine metabolizers genetically. And in those people who are slow caffeine metabolizers, we see increased risk for things like hypertension and heart attacks once folks exceed one cup per day. That's why it's important to get your genes tested. Now, the restriction or the constriction, I should say, of cerebral blood vessels reducing brain blood flow is not only something you might see if you're a slow caffeine metabolizer, but you also might see that type of effect if you have poor blood flow to the brain. You're eating a diet that doesn't support good cardiovascular health, you're prone to migraines or other neurological conditions. Again, you can't take this N equals one scan that you see on Instagram and apply that to you. But it is something that can happen in some people in response to coffee. If you have a preexisting heart condition, hypertension, arrhythmia, that's another reason to be cautious with coffee, especially if you have a pre existing cardiovascular issue and you're a slow caffeine metabolizer, can increase your risk of a heart attack. Is the Coffee clean, right? We know that people have a deleterious response, including a vasoconstrictive response and an irritable response to coffee that is not clean. Sipping microwaved coffee out of a Styrofoam cup that's pumping you full of microplastics or say, drinking coffee that is full of mold and mycotoxins. A notorious issue with a lot of coffees that haven't been selected properly. To optimize your coffee intake, you need to consider the source of the coffee, how you're wired up genetically, your risk of cardiovascular disease or previous history of cardiovascular issues, electrical or otherwise, your health status, your lifestyle. I mentioned the slow versus fast caffeine metabolizer, but there are other genetic variants that can cause caffeine to result in heightened anxiety. If you get a genetic test, there's a bunch out there, there's three by four, there's self decode, one that I've been using a lot lately because I'm now working with this organization is 10x. They have one called a precision genetic test that tells you everything you need to know about how your body and your brain respond to caffeine. These would all be ways that you can test things like CYP1A2 ADORA2A C O M T variants to hey, how am I genetically hardwired to handle caffeine and would I be a candidate to switch to decaf or caffeine free herbal beverages? You might just be somebody who has to wean yourself off of coffee. Understand when you see something like this, yes, that might be a problem for you and no it might not be. Get your genes tested, look into your health, your lifestyle, your sourcing of coffee and select your coffee wisely. 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