Coffee. If you’re like most people, it’s more than just a beverage. It’s a way of life, one that you probably can’t imagine changing.
Every day, coffee helps millions of folks—83 percent of U.S. adults, according to a 2013 National Coffee Association survey—get started and stay focused. I can relate, too. Without the occasional cup of joe to pick me up, I probably wouldn’t have survived my early years as a doctor, when long shifts in the cardiac ward were my norm.
The Debate Over Coffee’s Benefits
Without a doubt, we’re addicted to coffee. But is that addiction healthy or unhealthy?
Cardiologists traditionally have advised patients to not drink coffee—the assumption being that its caffeine content could promote not only the development of cardiovascular disease, but also heart attacks, strokes, and other acute cardiac events.
Recent studies, however, show that coffee may not be as problematic as once thought. Consumed in moderation, it may even be protective. Benefits are usually attributed to coffee’s high concentration of polyphenols—antioxidant nutrients that can help offset inflammatory mediators in the blood and protect against all types of disease, not just heart disease.
To get a better sense of your potential risks and/or benefits, 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. To the contrary, it may protect you so long as consumption isn’t excessive.
Risk of cardiac-related death
Coffee drinkers are less likely to die not just from heart attacks, strokes, and heart failure, but also from cancer, Alzheimer’s disease, and other causes. 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). Additional research has found similar results regardless of gender.
The drop in risk may be due in part to a separate 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. Combined, these coffee benefits greatly reduce the risk of a cardiac-related death.
Risk of arrhythmia and irregular heartbeats
On this point, I have to disagree with a study that found no connection between caffeine and arrhythmia, specifically atrial fibrillation, the most common type of serious arrhythmia. My clinical experience has shown me over and over that caffeine can indeed be problematic for people with poor heart rate variability or whose hearts are compromised by disease or a previous heart attack.
When caffeine enters the body, it stimulates the sympathetic nervous system. 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.
Risk of high blood pressure
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. However, there is one study that suggests coffee (and caffeine) may pose a risk if you already have high blood pressure.
An Italian study followed more than 1,200 adults, ages 18–45, with untreated mild hypertension. After 12 years, the researchers concluded that heavy coffee drinkers (4 or more cups a day) had a four times greater risk of a cardiac event, and moderate drinkers (1–3 cups) a three times greater risk.
The subjects in this study were all younger than typical heart patients, but it suggests to me that coffee could be bad for your health if you have a difficult time controlling your blood pressure; you may want to avoid it, regardless of your age.
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 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 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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