Drinking up to 5 cups of coffee a day has no long-term dangers and could even reduce risk of chronic illness, according to a review of 95 studies on coffee-drinkers
- Coffee has long been the subject of contested science, with research touting the bean for its health benefits and decrying the adverse effects of its high caffeine content.
- The latest roundup of evidence suggests there's no reason to be concerns about health risks from coffee, and the benefits are promising.
- Coffee can be part of healthy lifestyle and may help ward off chronic illness, so it's fine to drink if you enjoy it.
Coffee, the world's most popular psychoactive substance, contains hundreds of biologically active compounds, and researchers are still working to understand just how they affect the human body.
But good news if you're one of billions of java drinkers worldwide: the latest evidence indicates coffee doesn't present any long-term risk for health or increase the likelihood of heart problems, cancer, or other illness.
In fact, coffee actually has a wealth of health benefits, including reducing the risk of chronic diseases, according to a review published July 23 in the New England Journal of Medicine.
The authors of the review — experts from several medical schools including the Harvard T.H. Chan School of Public Health — reference more than 95 different studies to assess what we currently know about the health effects of coffee.
While too much coffee can cause side effects due to caffeine, this new analysis suggests it can be part of a healthy lifestyle for people who enjoy it.
Coffee-drinkers have a slightly lower risk of obesity, heart disease, and some forms of cancer and dementia
Coffee is associated with a wide range of health benefits, including a lower risk of obesity, since the caffeine it contains can boost metabolism and intensify the calorie-burning power of the digestive system.
Caffeine can also increase mental focus and also benefit brain health, particularly as we age — caffeine appears to be linked to a decreased risk of Parkinsons. Coffee, in moderation, is also linked to a lower risk of depression and suicide.
The drink is also linked to lower risk of many chronic illnesses such as cardiovascular disease, liver disease, breast cancer, prostate cancer, and several types of skin cancer.
It's not entirely clear whether the caffeine, other compounds, or both are responsible for these effects.
Beyond caffeine, coffee contains a huge number of other compounds that could affect health, including polyphenols, which could reduce inflammation, improve gut bacteria, boost metabolism, and moderate blood sugar, according to the review.
Worldwide, coffee drinkers also have a lower risk of dying from any cause. This is true of both caffeinated and decaf coffee alike, studies have found.
According to the review, these benefits are mild. Studies suggest a strong enough association that the benefits are promising, but not so much so that medical experts recommend starting to drink coffee if you don't already.
Not all the natural compounds in coffee are beneficial, though. One phytochemical called cafestol may actually increase cholesterol, although coffee brewed with a filter contains less of this substance.
Too much caffeine can make you jittery, but coffee is generally considered to be safe
As anyone who's had one espresso too many can attest, excessive caffeine can be unpleasant and uncomfortable, causing side effects like moodiness, anxiety, rapid heart rate, and insomnia.
In extremely high doses, caffeine can be dangerous and even fatal. However, you'd need to drink dozens of ordinary cups of coffee to ingest that amount of caffeine, and overdoses typically occur from highly-concentrated caffeine supplements in pill or powder form.
And contrary to some theories, caffeine doesn't appear to be bad for your heart long-term. Multiple studies have compared caffeine and risk of cardiovascular illness, finding no association, although caffeine can temporarily affect blood pressure for people who don't regularly consume.
Pregnant women, however, are advised to limit caffeine consumption to 200 mg a day, half the typical recommended amount, since we don't fully understand how caffeine can affect a developing fetus.
For everyone else, though, coffee is generally considered to be safe to enjoy in moderation, and potentially offers a small boost to overall health and wellbeing.
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