So is coffee good for us or not? There have been troubling worries raised in the past — especially about risks involving cancer, heart disease, and the liver. But the research over the past couple of decades has flipped the script when it comes to coffee and our health. And this latest study finally puts to rest one of the most common concerns I hear all the time from my patients, especially when they’re older.
Table of Contents
Heart Health
The biggest worry most people have when it comes to coffee relates to the heart, and that’s where this recently published clinical trial comes in.
What’s the connection here?
Coffee contains caffeine, and caffeine is a stimulant. Stimulants can be super useful. Caffeine boosts alertness, increases exercise capacity, and can enhance mood. But there are some other effects that cause the worry. Specifically, caffeine can elevate heart rate and blood pressure. And we know that, when it comes to heart health, we generally want to do the opposite. So that raises the question of whether drinking coffee is good for our hearts.
It’s something doctors have been paying attention to for a long time. A review of the literature published back in 2004, for instance, warned we should be alert to potential problems. The author made the alarming claim that caffeine use could account for around 14% of deaths from heart attacks and 20% of those from strokes [1].
Claims like these caused doctors and other health experts to warn about coffee consumption — especially for those who have heart conditions like irregular heartbeats.
But evidence has been steadily building that this early assessment was wrong.
Let’s look at hypertension first. This is when blood pressure levels are too high. Since caffeine raises blood pressure, at least in the short-term, this is a key area to look at. So does regular coffee consumption increase our risks for hypertension?
A meta-analysis published in 2018 pulled together the existing evidence. Their assessment included 10 cohort studies with about 250,000 people. The findings were the opposite of what we might expect. Instead of increasing the risk of hypertension, coffee drinking was actually associated with a lower risk. Specifically, the risk of high blood pressure was cut by 2% with each additional cup of coffee per day compared with those who didn’t drink coffee [2].
But higher blood pressure in itself isn’t really the worry at the end of the day. It’s what higher blood pressure can lead to. That extra stress on the heart and blood vessels is linked to dangerous conditions like plaque buildup, heart attacks, and strokes. So we don’t want to just look at studies on hypertension. It’s also important to look at the connection between coffee and health problems like these.
And when we do that, we find some surprises. A massive cohort study in 2009 involved over 80,000 women and lasted 24 years. It looked specifically at strokes. The researchers found those who drank the most coffee had the lowest risk of having a stroke. For those who drank 2-3 cups of coffee a day, it was 19% lower than for non-coffee drinkers [3].
Another large cohort study in the U.K. published in 2022 investigated deaths from heart disease. Compared to those who didn’t drink coffee, those consuming up to 3 cups a day had a 17% lower mortality rate [4].
Even for those who had previously had a heart attack, drinking more coffee led to better outcomes. A Swedish study followed participants with a prior heart attack for 8 years. Those who drank more coffee had up to a 40% lower risk of dying from heart disease than those who drank none or just one cup a day [5].
But what about the area of irregular heartbeats? It is commonly thought that caffeine can make this more likely. One of the more worrying types of irregular heart rhythms, or arrhythmias, is atrial fibrillation. This is when the upper chambers in the heart aren’t beating in their regular rhythm. When this happens, we feel like our heart is racing, fluttering, or skipping beats. It’s like a band that’s gotten out of sync, and the members are no longer playing together. Atrial fibrillation can be dangerous because it increases the risk of developing blood clots, which can cause strokes.
A meta-analysis examined 7 observational studies involving over 100,000 people. It found that caffeine consumption wasn’t associated with a greater risk of atrial fibrillation. In fact, researchers concluded that low-dose caffeine may even help guard against the condition [6].
This finding was backed up by another meta-analysis and a large Danish cohort study that the clinical guidelines reference [7].
And here’s where we get to the brand-new study I want to talk about. It looked specifically at patients who were already diagnosed with atrial fibrillation. These are the people whom doctors have often advised to steer clear of coffee and caffeine because these patients are high risk.
If we were going to see heart problems from coffee, this is the population where we’d see it.
The people in the study were divided into two groups: daily and non-daily coffee drinkers. They kept track to see how many experienced strokes, heart attacks, heart failure, or death due to heart problems.
Here’s what they discovered. The risk for these serious health problems was 23% lower for the daily coffee drinkers [8].
You can see why I say this study adds the final nail in the coffin for worries about coffee and heart problems. This is a population where traditionally we’ve had the most concern about the effects of coffee. And this study found it actually helps.
But I want to add three important cautions.
First, the timing of our coffee intake has a huge impact on our health, as does the amount. We can certainly have too much caffeine. And I’ll come to what the right timing and amount is in a moment. So we’re not talking about unusually large intakes here. But the clinical guidelines say that, even for people who experience arrhythmias, modest amounts of caffeine appear to be safe. Even though it seems logical that coffee might cause arrhythmias, the evidence so far suggests that for most people, it doesn’t. But there will be some individuals who are especially sensitive and may need to cut back their coffee intake [9].
The second caution has to do with cholesterol. We have research of over 132,000 adults showing no association between the intake of filtered coffee and total cholesterol [10].
But “filtered” turns out to be a key qualifier here. With unfiltered coffee, we do see increases in cholesterol levels, including LDL cholesterol. Research has shown that daily ingestion of four to six cups of boiled (unfiltered) coffee for nine weeks can raise total cholesterol and LDL cholesterol [10]. Clearly, not what we want. So the research supports avoiding unfiltered coffee. That means steering clear, for instance, of a French press. It’s also worth considering filter paper if you use an espresso machine.
And the final caution is that we need to be careful about what we add to our coffee. If we use cream and sugar, we can offset coffee’s positive effects.
For instance, drinking black coffee is linked to losing weight, but adding sugar to your coffee is connected to gaining weight in a recent study [11].
Liver, Cancer
Before we look at when to drink coffee and the amount that’s best for our health, we need to look at 2 other health concerns.
Heart health is probably what most people think of first when it comes to coffee. But it isn’t the only concern. Sometimes my patients also ask about liver health and cancer. So is there anything we need to worry about in these areas?
The concern about the liver is this. Caffeine is processed and broken down by the liver. It would make sense that having too much could strain the liver, possibly leading to damage over time.
That’s the theory. What have researchers found?
A large review published in the Journal of Clinical and Experimental Hepatology notes that drinking 2 or more cups of coffee a day improves liver function. It also protects against the progression of almost all forms of liver disease [12].
A more recent analysis of nearly 500,000 participants in the UK Biobank with a median follow-up period of almost 11 years reinforces these conclusions. Researchers observed a 21% lower risk of chronic liver disease and a 49% reduction in death from this condition when comparing regular coffee drinkers to non-drinkers [13].
The authors of another meta-analysis found the connection between regular coffee consumption and liver health so strong that they even wrote that caffeine can be considered a potential drug for preventing and treating various liver diseases [14].
In other words, they said caffeine is like medicine for the liver. That’s the exact opposite of being a damaging strain on the liver.
Okay, but what about cancer? There have been some concerns about this in the past. For instance, a broad study tried to trace connections between cancer rates on a population level and the amount of coffee consumed in particular countries. The authors detected an association between higher coffee intake and pancreas, prostate, and other cancers [15].
The World Health Organization even listed coffee as “possibly carcinogenic” in 1991 [16].
But a re-evaluation of more recent evidence caused them to reverse course in 2016. They said the evidence did not show a risk of cancer [17].
More recent research has pushed things even further. Scientists recently combined the results from 28 individual meta-analyses. In other words, they looked at mountains of data.
Their conclusion? The highest quality evidence suggests that as coffee consumption goes up, the risk of developing liver or endometrial cancer goes down [18].
Furthermore, they didn’t find solid evidence that coffee causes any type of cancer.
A separate study looked specifically at coffee consumption and prostate cancer risk. Once again, a higher intake of coffee was associated with a lower risk of cancer [19].
So for all these areas — heart health, liver issues, and cancer — we see a similar story. While we used to worry about negative health impacts, more recent evidence keeps uncovering positive ones instead.
Practical Issues
But if we want to reap the benefits from coffee, we need to use it properly. This means paying attention to timing and quantity. So when should we drink coffee? And how much is safe?
You’ll find plenty of health influencers giving this advice: “Why the First Thing You Drink in the Morning Absolutely Shouldn’t Be Coffee” [20].
What’s the logic behind it?
There are two main reasons given. First, people claim it can cause an unwanted rise in cortisol levels. Cortisol plays many important roles in the body. One of them is helping you feel awake and alert. Cortisol levels naturally rise rapidly when we first wake up, peaking after about 30 minutes [21].
But having too much over the long term causes negative effects like weight gain, raised blood pressure, muscle weakness, and osteoporosis.
And yes, coffee can make your cortisol levels go up. That’s why some people think it’s better not to drink coffee right when you wake up, because your cortisol is already at its highest then.
Here’s why this logic doesn’t hold up.
Coffee loses much of its power to elevate cortisol levels once our bodies get used to it. After just 5 days of regular coffee intake, people stopped having a cortisol response to their initial cup of coffee [22].
So the first reason given to avoid an early morning coffee is flawed. It doesn’t appear to be a problem for our cortisol levels.
The second reason relates to our adenosine levels. Adenosine helps trigger sleepiness. It naturally builds up in the body during the day. Caffeine blocks adenosine, which is why it keeps us awake.
The theory here is that when we wake up, our adenosine levels are at their lowest. So caffeine won’t have much, if any, benefit because there is hardly any adenosine to block.
There are two problems here. First, blocking adenosine isn’t the only impact of coffee. So even if it isn’t as effective for this purpose first thing in the morning, it could still make sense to drink it right away. Second, caffeine stays in your system a really long time. So its effect in blocking adenosine continues long after you drink it. That means delaying it a bit isn’t going to make much difference.
In fact, this gives us a reason not to delay drinking our coffee. The average half-life of caffeine in the human body is about 5 hours [23].
That means after 5 hours, you’ll still have 50% of the caffeine in your system. After 10 hours, it would be 25%. After 15 hours, 12.5% would remain.
Since caffeine is a stimulant, it affects your sleep. Some people will say that caffeine doesn’t affect their sleep and that they can still get to sleep easily even if they have a coffee late at night. Sure, but even if you can get to sleep, caffeine affects the quality of your sleep. You likely won’t be as rested in the morning.
So it makes sense to have our coffee earlier in the day to avoid degrading our sleep quality. I tell my patients to aim to have their last cup within 4 hours of waking up.
Plus, in January of this year (2025), published in the European Heart Journal, a study of 40,725 adults suggests that drinking coffee in the morning may be more strongly associated with a lower risk of mortality than drinking coffee later in the day [24].
And a large 2024 review looked at all the current evidence regarding an ‘afternoon crash.’ It concluded that there’s no evidence of this claim [25].
So if you want to delay your first cup of coffee by a couple of hours because of what you’ve heard an influencer say, that’s entirely your call. But I wouldn’t have any more caffeine after 4 hours of waking up.
But what about quantity? What’s the right amount of coffee to gain its benefits without having too much? The U.S. Food and Drug Administration has set a level of 400 mg a day for healthy adults as an amount not generally associated with negative effects [26].
What does that translate into in terms of cups of coffee? The amount of caffeine in coffee ranges widely depending on the type, how it’s brewed, and other factors. A finer grind, for instance, releases more caffeine when brewed. A cup of coffee may have as little as 80 mg. On the other hand, a larger coffee at a coffee shop could have 400 mg or more. Most sources suggest a typical cup of coffee brewed at home has around 100 mg.
Looking at how much coffee was used in the studies and what doctors recommend, having 2-3 cups a day seems just right. At this level, for most people, we can lock in the benefits without risking side effects.
Plus, that was the intake the authors of the new study on coffee and atrial fibrillation found. 2-3 cups of coffee was associated with the lowest risk of heart attacks, strokes, and deaths [8].
Reference List
1. https://journals.lww.com/bsam/abstract/2004/01000/critical_review_of_dietary_caffeine_and_blood.10.aspx
2. https://www.nature.com/articles/s41371-017-0007-0
3. https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.108.826164
4. https://academic.oup.com/eurjpc/article/29/6/982/6512055
5. https://pubmed.ncbi.nlm.nih.gov/19249420/
6. https://pubmed.ncbi.nlm.nih.gov/24009307/
7. https://www.uptodate.com/contents/cardiovascular-effects-of-caffeine-and-caffeinated-beverages
8. https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-024-03817-x
9. https://www.uptodate.com/contents/cardiovascular-effects-of-caffeine-and-caffeinated-beverages
10. https://www.uptodate.com/contents/cardiovascular-effects-of-caffeine-and-caffeinated-beverages
11. https://www.sciencedirect.com/science/article/pii/S0002916523661702
12. https://pmc.ncbi.nlm.nih.gov/articles/PMC4862107/
13. https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-021-10991-7
14. https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2022.1030173/full
15. https://pmc.ncbi.nlm.nih.gov/articles/PMC2008583/
16. https://www.iarc.who.int/en/media-centre/pr/2016/pdfs/pr244_E.pdf
17. https://www.iarc.who.int/en/media-centre/pr/2016/pdfs/pr244_E.pdf
18. https://pmc.ncbi.nlm.nih.gov/articles/PMC7003434/
19. https://pubmed.ncbi.nlm.nih.gov/33431520/
20. https://www.wellandgood.com/coffee-first-thing-morning/
21. https://www.sciencedirect.com/science/article/abs/pii/S1087079213000518?via%3Dihub
22. https://pmc.ncbi.nlm.nih.gov/articles/PMC2257922/
23. https://www.ncbi.nlm.nih.gov/books/NBK223808/
24. https://academic.oup.com/eurheartj/article/46/8/749/7928425
25. https://pmc.ncbi.nlm.nih.gov/articles/PMC10930107/
26. https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much
