How does coffee affect blood pressure and heart health?
“Caffeine increases blood pressure, regardless of who you are, but especially in people who aren’t used to consuming caffeine. The effect somewhat quiets once you’ve become habituated (which will probably take you around a week or less). Caffeine, in the form of coffee or tea, does not seem to be associated with increased cardiovascular disease risk, except if you consume none of it, or if you consume a lot of it (6 cups or more).” Recently, I’ve been focusing a considerable amount of attention on caffeine. I even had a subscriber joke if I had invested in a caffeine company – the answer is ‘no’, but have been focused on caffeine, because I saw surprisingly great interest in my video series on YouTube investigating the role caffeine has on performance – be it endurance or resistance training. So, I decided to hop on that train again and investigate the role caffeine has on heart health – it was a fascinating tale woven between five studies I analyzed, and while the video series was a complete flop, I’ll go ahead and tell you the story, anyway.
At first, I became intrigued by this topic, because I was afraid I was dealing with high blood pressure, myself. I thought maybe caffeine was a contributing factor, and it turns out that it was, along with unrelenting stress; but, the latter aside, I ended up reading two studies on the effect
caffeine has on blood pressure.
1. Does coffee increase blood pressure? These studies [Figure 1] indicated that caffeine may increase blood pressure, but there were some inconsistencies, because in certain populations, it didn’t seem to have an effect, and in others, it did. So, breaking this down further – looking at non-habituated caffeine consumers and habituated caffeine consumers, blood pressure was elevated in non-habituated caffeine consumers (individuals that do not regularly consume caffeine and if they do, small amounts) [Figure 2]. But, digging deeper into the details, it became clear that another effect was present – a gene difference.
2. How do genetic differences affect blood pressure? If you’ve been following my work up to now, you’ve heard me speak on this topic before – we have a genetic difference in our liver, and that genetic anomaly leads to changes in our ability to process caffeine. What’s known as a genetic variant (mutation) of a gene that holds the information for the production of our caffeine metabolizing enzyme seems to indicate other effects beyond just fast and
slow caffeine metabolism – specifically, blood pressure effects [Figure 3]. So, looking back at some of the data I analyzed, people with a fast caffeine metabolism gene (the AA variant) tended to have increases in diastolic blood pressure, but not systolic; however, people with a slow caffeine metabolism (the AC variant) experience an increase in both measures of blood pressure [Figure 4]. But, the plot thickens, because slow caffeine metabolizers also have elevated blood pressure, even before the sweet morning elixir
reaches their lips. Those that are habitual caffeine consumers with a slow caffeine metabolism enzyme have elevated blood pressure and then experience even higher blood pressure from caffeine consumption [Figure 5].
3. Does coffee hurt heart health? So, that led me to think – does caffeine, and gene difference, then correlate with cardiovascular disease (heart attack, stroke, peripheral artery disease, etc.)? To find out the answer to this query, I analyzed three more studies and here’s what I uncovered. When looking at caffeine consumption, there was a U-shaped trend – meaning, no caffeine (more specifically, coffee – which may make a difference, so I’d like to point it out) consumption was associated with more heart disease risk [Figure 6]. However, some (1-2 cups of coffee a day) caffeine consumption did not associate with heart disease risk. Finally, consuming large amounts of caffeine (6+ cups) associated even more strongly with heart disease risk.
But, what about the caffeine metabolizing effect, the gene effect? Surprisingly, the exact same trend was seen – indicating no ‘out of the ordinary’ effect of caffeine metabolism. Oddly enough, other studies did indicate a negative correlation with slow metabolizers – meaning, slower metabolism, higher heart disease risk, but more consistently, I saw data indicating no negative effect. So, what’s going on here? I think there are too many leaks in the investigation for me to plug with the short time frame I have, but researchers also seem pretty unsure about what to make of this situation. It’s possible the form the caffeine comes in may matter – coffee vs caffeine pills, for example. Conclusion But, here’s my take away: Caffeine increases blood pressure, regardless of who you are, but especially in people who aren’t used to consuming caffeine. The effect somewhat quiets once you’ve become habituated (which will probably take you around a week or less). Caffeine, in the form of coffee or tea, does not seem to be associated with increased cardiovascular disease risk, except if you consume none of it, or if you consume a lot of it (6 cups or more). I think the jury is still out on the gene effect – it’s something I’ll hope to revisit in a few years when the research is better established on the matter, but if you’re a fast metabolizer, you likely have little to worry over. However, I’d also like to point out that ‘slow’ caffeine metabolizers are labeled with an ‘AC’ caffeine metabolizing gene, but in reality, there are also individuals with a ‘CC’ gene and it’s *this* gene variant that has caused the most problems in caffeine studies I’ve read over – so, it may be an injustice to lump ‘AC’ gene variant carrying individuals (slow caffeine metabolism) with ‘CC’ gene variant carrying individuals (even slower caffeine metabolism), because any effects may get diluted by the larger sample of ‘AC’ individuals. If you would like to have full access to my investigations, exclusive content not available to the public, as well as be part of a community of science minded individuals, I recommend you join my Physionic Insiders Community.