Coffee is a morning necessity for many people. The much-loved beverage can enhance mental focus, elevate mood and delay fatigue.
The benefits of drinking coffee go beyond its mental perks. Research suggests that if you drink enough of it, coffee can protect your long-term health.
There is a tipping point, though. Drinking too much coffee can cause unwanted side effects and, as some research suggests, may also increase the risk of heart disease.
Is coffee healthy?
Plenty of evidence suggests that drinking three to five cups of coffee a day, and in some cases more, lowers the risk of many chronic diseases. (Researchers define a cup of coffee as six or eight ounces.)
Drinking coffee, regular or decaf, has consistently been found to protect against type 2 diabetes. A large review of studies, published in 2017, reported that as coffee consumption increased from one to six cups a day, the risk of diabetes declined.
Among healthy people, coffee may also benefit heart health. Observational studies have linked drinking up to three cups a day (versus none) to a lower risk of heart disease, stroke and death from cardiovascular disease.
And according to data published this year from three long-term heart studies, drinking one or more daily cups of caffeinated coffee may reduce the risk of heart failure. Heart failure occurs when the heart muscle weakens and can’t pump enough blood fast enough to meet the needs of the body; risk factors include high blood pressure, heart attack, diabetes and obesity.
Drinking coffee has also been associated with protection from gallstones, Parkinson’s disease, liver disease and certain cancers.
Heavy coffee drinking (six or more cups a day), however, has been tied to modest increase in heart disease risk. A 2020 study also linked drinking nine or more cups of unfiltered coffee a day (for example, Turkish or French press) to an increased risk of cardiovascular death.
What’s in coffee?
Coffee contains a wide range of phytochemicals, some of which have antioxidant and anti-inflammatory properties. Compounds in coffee called diterpenes are thought to have anti-cancer effects.
Coffee also contains magnesium, a mineral that helps the body secrete and use insulin properly.
Caffeine stimulates the central nervous system, increasing alertness, and it also acts as an antioxidant. Decaffeination, therefore, reduces the antioxidant potential of coffee.
A byproduct of caffeine metabolism, paraxanthine, has been shown to slow the growth of scar tissue, which may help protect liver health.
Contrary to popular belief, drinking caffeinated coffee isn’t dehydrating. Even though caffeine is a mild diuretic (a substance that causes you to urinate), the amount of water in coffee offsets this.
Caffeine’s downside, intake guidelines
For healthy adults, Health Canada recommends no more than 400 milligrams of caffeine a day, an amount found in roughly three eight-ounce cups of brewed coffee, six one-ounce shots of espresso or 10 eight-ounce cups of tea.
Excess caffeine can cause headaches, make you irritable or anxious, interfere with sleep, upset digestion and spike blood pressure. Caffeine sensitivity varies from person to person, so some people can experience these effects with small amounts.
Women who are pregnant or breastfeeding, or planning to become pregnant, should limit caffeine intake to 300mg a day. High amounts of caffeine may increase the risk of miscarriage or low birth weight.
Kids, who are at greater risk of experiencing caffeine side effects, shouldn’t consume more than 45mg (4 to 6 years), 62.5mg (7 to 9 years) and 85mg (10 to 12 years).
It’s wise to limit caffeine if you have anxiety, difficulty controlling your blood pressure, insomnia or osteoporosis and get too little calcium from your diet.
If you have gastrointestinal reflux disease (GERD), drinking coffee – regular or decaf – can trigger or worsen symptoms.
How to cut back on coffee
If your coffee habit needs a reset, cut back gradually to help prevent withdrawal symptoms such as headache, irritability, fatigue and muscle pain.
Set a goal to eliminate caffeine after noon; replace with sparkling water, decaffeinated coffee or herbal tea.
Green or black tea have considerably less caffeine than regular coffee. So does cola, but I don’t recommend drinking it (or any soft drink). Soft drinks sweetened artificially or with sugar are highly processed beverages that should be limited.
If you buy your coffee, order half regular, half decaf to dilute its caffeine content. And consider ordering a smaller size.
How much caffeine in a cup?
Here’s how different types of coffee compare when it comes to caffeine (in milligrams):
- Coffee, roasted, ground, filter drip, 8 ounces: 179
- Coffee, instant, 8 ounces: 76 - 106
- Coffee, decaffeinated, 8 ounces: 3
- Espresso, 1 ounce: 64
- Starbuck’s Coffee, Grande, 16 ounces: 310
- Starbuck’s Coffee, Venti, 20 ounces: 410
- Starbuck’s Latte, Grande, 16 ounces: 150
- Tim Horton’s coffee, large, 20 ounces: 270
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD
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