By Stephen T. Sinatra, M.D., F.A.C.C., F.A.C.N., C.N.S., C.B.T.
Coffee. If you’re like most people, it’s more than just a beverage. It’s a way of life, and one you probably can’t imagine changing.
In fact, a 2019 survey commissioned by the National Coffee Association said that 63 percent of U.S. adults reported drinking coffee “yesterday” – with 71 percent having downed a cup in the “past week,” and 79 percent at some point in the “past year.”
That’s a lot of joe.
I’m not as big a coffee drinker as I used to be, but I can relate. Without coffee to pick me up and get me focused, I probably wouldn’t have survived all those long shifts in the cardiac ward as a young doctor.
The Debate Over Coffee’s Health Benefits
With so many of us identifying as coffee drinkers—some might dare say “addicts”—you may wonder what effect it’s having on your health. Is it good for anything more than a shot of instant energy?
There are certainly plenty of studies out there that say it is. More than one published just this year has associated moderate coffee consumption, about three cups a day, with lower mortality. Other studies have linked it with lower risk for a range of problems, including type 2 diabetes, depression, and Parkinson’s disease.
The benefits of coffee are largely thought to be tied to its high concentration of polyphenols—antioxidant nutrients that help offset inflammation and protect against disease throughout the body. (Polyphenols are found in all plant foods and also happen to be part of the magic in my favorite health-promoting food, olive oil.)
Sounds good, right?
Maybe…or maybe not, depending on your cardiovascular status. Cardiologists traditionally have advised patients to stay away from coffee, on the assumption that its caffeine content could lead to cardiovascular disease, heart attacks, strokes, and other acute cardiac events.
To get a better sense of your potential risk or benefit, let’s take a closer look at some of the research around coffee’s specific effects on the heart.
7 Ways Coffee May Affect Your Heart
Risk of developing heart disease
According to two large meta-analyses—one including more than 400,000 cohort subjects, and the other more than 1 million—there is no association between drinking coffee and the long-term risk of developing heart disease. In fact, the first study found that moderate coffee consumption reduced this risk in women, and the second found that 3–5 cups of coffee a day reduced risk across the board.
This would seem to put to rest old fears that coffee has similar negative effects on the heart as smoking and heavy drinking. It also makes perfect sense when you account for the beneficial effect coffee has on some of the biggest risk factors for heart disease, like type 2 diabetes, obesity, and high blood pressure. Reduce or eliminate those issues, and there’s less wear and tear on your heart and arteries. There’s also one recent study that suggests coffee may help protect against arterial calcification—but only in nonsmokers. (Another great reason to quit!)
Risk of cardiac-related death
If coffee drinkers are less likely to develop heart disease, you’d expect them to be less likely to die of cardiovascular events, too—and that’s exactly what the research shows. However, coffee drinkers aren’t just less likely to die from heart attacks, strokes, and heart failure. They’re also less likely to die from cancer, Alzheimer’s disease, and other causes.
Where cardiovascular events are concerned, though, The Nurse’s Health Study, a long-running look at more than 80,000 women, found a specific reduction in stroke risk among women who drank 2-3 cups per week (a 19 percent reduction) and who drank 4 or more cups per week (a 20 percent reduction). Another long-running study, EPIC (European Prospective Investigation into Cancer and Nutrition) found similar outcomes after following over a half million people for an average of 16 years. Additional research has found similar results regardless of gender.
The drop in risk may be due in part to a finding by Greek researchers that coffee improves endothelial function. When the endothelial cells lining your arteries are healthy, blood flows more easily, the heart doesn’t have to work as hard, and you’re less likely to develop atherosclerosis. Another possibility is something the EPIC researchers uncovered…Women in their study were also likely to have lower levels of lipoprotein(a), CRP, and HbA1c. These factors are all associated with artery-damaging inflammation. Both possibilities are certainly worthy of further research.
Risk of arrhythmia and irregular heartbeats
Studies continue to find no connection between caffeine and risk of arrhythmia, specifically atrial fibrillation, the most common type of serious arrhythmia. However, here I have to disagree with the science and go with my experience. When I was actively seeing patients, I saw over and over that caffeine can be problematic for people with poor heart rate variability or whose hearts are compromised by disease or a previous heart attack. I advised these patients to avoid it altogether, whether in coffee, tea, or chocolate.
Caffeine is a stimulant. When it hits the bloodstream, it turns on the sympathetic nervous system and initiates a stress response. This causes blood pressure to rise, adrenaline to be released, and instantly requires that the heart beat harder and faster. If your heart function is already less than ideal, this can be a recipe for real trouble. On the other hand, if your heart is healthy, the latest research shows that regular caffeine consumption may actually have a protective effect.
We used to think that long-term caffeine consumption could increase the probability of developing high blood pressure, but multiple studies have proven that idea to be untrue. Some even suggest the opposite – that caffeine may help protect against high blood pressure.
But what if you already have high blood pressure? This is an important question given that about 1 in 3 American adults falls into this category. The science here is mixed. An Italian study that followed more than 1,200 adults, ages 18–45, with untreated mild hypertension concluded that heavy coffee drinkers (4 or more cups a day) had four times greater risk of having a cardiac event, and moderate drinkers (1–3 cups) a three times greater risk. However, subsequent research has stated that coffee consumption is probably safe—though it should be done cautiously.
My advice here would be to listen to your body, and to drink moderately and mindfully. If you have a cup of coffee and notice that your blood pressure goes up, it’s probably best if you steer clear. The same is true if you have trouble controlling your blood pressure even when you’re not drinking coffee.
Risk of unhealthy cholesterol
There is evidence that unfiltered coffee has the power to increase LDL cholesterol. Generally I don’t take issue with LDL levels unless they exceed 300 mg/dL—so if your cholesterol is extremely elevated, make sure your brew is filtered.
Risk of nutrient deficiency
Coffee will get you going—and as any avid drinker will tell you, one of the places you’ll be going is straight to the bathroom.
Caffeine is a diuretic. As such, it carries some of the same risks as more potent diuretics, including the loss of vital water-soluble nutrients like magnesium, potassium, and B vitamins. Granted, this risk is relatively small with coffee—but it’s important for patients with heart disease to be aware of it, since small deficiencies in nutrients like magnesium can have a big impact on heart function.
Risk of disturbed sleep
All coffee drinkers will probably admit to using it to stay awake at some point. Again, this is a result of caffeine’s stimulatory effect. I don’t like coffee after midday because it can linger in the body and cause restless or sleepless nights. Sleep deprivation is linked to compromised health: the body responds to it by increasing the secretion of stress hormones like cortisol, which stoke the flames of inflammation. On the other hand, research has shown that sleeping more than 7 hours a night can help you lower your risk of heart disease. If coffee is getting in the way of your being able to sleep, then I’d say it’s bad for your health.
The Sinatra Solution: Everything in Moderation
Essentially, the question of whether coffee is good or bad for you boils down to weighing the negative effects of caffeine against the protective antioxidant benefits of coffee’s polyphenols.
In my opinion, there’s nothing wrong with one or two cups of coffee a day. So if you can’t live without your daily jump start, don’t worry. Just don’t overdo it with sugar or artificial sweeteners, which can offset coffee’s benefits.
I don’t recommend too much more than that, however, since there may be some additional risk for anyone with diagnosed cardiovascular disease or a history of heart attack. The protective benefits of coffee are certainly something you want to take advantage of, but that desire needs to be weighed carefully with the downsides of caffeine.
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© 2016, 2019 Stephen Sinatra, MD. All rights reserved.