Buzz
A recent study making headlines suggests that individuals who drink two to three cups of coffee a day tend to live longer than those who don't. But should everyone aim for two to three cups? Not exactly. Let's examine where these findings come from.
Two to three cups for a longer life, perhaps
This recent research uses data from the UK Biobank, where the average participant is 58 years old, more than half are women, and around 95% are white. The researchers tracked participants for an average of 12 years after they reported their coffee consumption habits.
When looking at death rates from all causes, people who consumed two to three cups of coffee per day exhibited the lowest risk, regardless of whether it was ground, instant, or decaf coffee. For heart disease, those who drank one cup daily had the lowest risk, while for arrhythmia (irregular heartbeat), the optimal range seemed to be four to five cups. In the case of arrhythmia, decaf coffee did not show a reduction in risk.
However, this study has its limitations if you're using it to decide how much coffee to drink. The sample of middle-aged British individuals may not reflect global coffee habits, and coffee consumption isn't random. Factors like income, social class, and perceived health risks can all influence how much coffee someone chooses to drink. Additionally, the study relied on self-reported data, assuming participants maintained consistent coffee consumption over the years without reassessing their habits.
Three to four cups for other health benefits
A review published in the BMJ analyzed numerous previous coffee studies and found that coffee drinkers tend to have lower risks of cardiovascular diseases, including strokes, certain cancers, and some liver and gastrointestinal issues. The quantity of coffee linked to a reduced risk generally ranged between three to four cups per day.
The author of this review stated that people shouldn't start drinking coffee solely based on these findings but mentioned that for those who already drink coffee, it “can be part of a healthy diet.”
One of the challenges in understanding coffee's effects is the large variety of bioactive compounds it contains, with caffeine being just one of them. The chemical composition can also vary depending on the type of beans used and the method of preparation.
Additionally, studies often don't randomly assign participants to coffee-drinking groups. Instead, they typically ask individuals how much coffee they already consume. If someone is advised by their doctor to limit caffeine due to concerns about blood pressure, for example, they would be categorized as a non-coffee drinker in the study. This means those who avoid coffee might have different health risks than regular drinkers, which isn’t always taken into account.
The authors emphasize that 'Robust randomized controlled trials are needed to understand whether the observed associations are causal [i.e., caused by coffee].'
To play it safe, four cups or fewer is the recommended limit.
According to the U.S. Dietary Guidelines, for healthy adults, the FDA has set a daily caffeine intake of 400 milligrams as a level generally not linked to harmful effects. For pregnant individuals, the recommended limit is 200 milligrams per day.
In simple terms, coffee isn’t so essential for health that experts recommend everyone drink it. But it’s also not harmful enough to set a strict limit. Instead, they provide a general guideline that is considered safe. (Extremely high doses of caffeine could be harmful, but they believe this amount is not excessively high.)
So how much coffee does this mean? Most brewed coffee contains roughly 100 milligrams of caffeine per 8 fluid ounces, though this can vary depending on the brand and brewing method. For instance, a 14-ounce cup of Dunkin coffee has 210 milligrams, while a 16-ounce cup from McDonald's has 145 milligrams. You can check the caffeine content in your preferred drink at Caffeine Informer.
Before you grab your coffee, it's important to remember that the guidelines also highlight that sweetened coffee drinks are a common source of added sugars in our diets. We should limit added sugars to less than 10% of our total calories, or around 50 grams. For example, an iced coffee from Starbucks contains 20 grams of sugar, while a caramel Frappuccino has 54 grams. Black coffee, however, contains almost no sugar at all.
