For years coffee has traveled with a small warning hanging on the cup: watch your heart. The American Heart Association now significantly debunks that suspicion. For most adults, up to 400 milligrams of caffeine per day, corresponding approximately to three to five American cups, is considered safe consumption. The mocha can stop showing up accompanied by the lawyer.
Matteo Bassetti also relaunched the news in Italy, summing up the document on social media with an enthusiastic “Long live coffee”. The summary captures the most reassuring part of the news: moderate consumption is associated with a lower risk of some cardiovascular and metabolic diseases. Inside the same cup, however, end up observational studies, a very precise clinical trial and a substance, cafestol, which deserves a decidedly less heroic role.
The reference is new scientific statement published on Circulation. The panel reviewed available research on caffeine and cardiovascular health, ranging from blood pressure to arrhythmias, from type 2 diabetes to heart failure. A scientific statement photographs what we know and the questions still open; doesn’t deliver a prescription with the coffee pot.
How many are five cups really
The number destined to remain imprinted is five. However, the AHA talks about eight-ounce American cups, about 240 milliliters, and black coffee without syrups, cream or mountains of sugar. The most useful reference remains the overall quantity of caffeine, because preparation, mixture and portion size change the content of the drink significantly.
The bill also includes tea, cola, chocolate, some medicines, supplements and energy drinks. The 400 milligrams therefore describes a general safe threshold for many healthy adults. No one has to reach it with the punctuality of someone who is completing an antibiotic therapy.
The European Food Safety Authority considers a daily intake of up to 400 milligrams from all sources to be of no particular concern in healthy adults. During pregnancy and breastfeeding the threshold drops to 200 milligrams per day.
Individual response continues to make a big difference. Genetics, age, habit, medications and health conditions influence how caffeine is metabolized. For some, an espresso after dinner is almost a herbal tea; for someone else, four in the afternoon marks the beginning of a long night spent staring at the ceiling.
Palpitations, agitation, tremors, temporary increases in blood pressure and disturbed sleep indicate that the personal dose has already been exceeded, even when the general limit still appears far away. The AHA highlights precisely this variability: a quantity tolerated without problems by one person may be excessive for another.
What changes for heart, stroke and diabetes
Overall, regular and moderate consumption of caffeinated coffee is associated with a lower risk of type 2 diabetes, coronary heart disease and stroke. For heart failure, the most favorable outcomes are mainly concentrated on low or moderate quantities; beyond four cups a day, some research observes a possible increase in risk.
The word to keep close is “associated”. Most studies follow the habits of very large groups over time and compare the health of those who drink coffee with that of those who avoid it. This allows us to observe consistent links, while it remains more difficult to attribute the benefit directly to the drink.
Coffee drinkers may have different diets, physical activity, habits and social conditions. All variables capable of slipping between the cup and the result. The AHA itself recognizes that the majority of available evidence is observational and calls for more randomized clinical trials.
Coffee also contains hundreds of compounds in addition to caffeine. Some have antioxidant and anti-inflammatory properties and could contribute to the observed effects. Establishing how much depends on caffeine and how much on the rest of the bean is still complicated: they all arrive in the drink together, without an identification tag.
The surprise concerns atrial fibrillation
One of the most interesting findings concerns atrial fibrillation, a heart rhythm disorder for which coffee has long been considered a possible trigger. The most recent analyzes do not show a general increase in risk with moderate consumption. One clinical trial even observed fewer relapses among patients who continued drinking it.
The study, published on JAMAinvolved 200 adults with persistent atrial fibrillation, or atrial flutter accompanied by previous fibrillation, who successfully underwent electrical cardioversion. The average age was 69 years and 71% of the sample was men.
For six months, half of the participants were asked to drink at least one cup of caffeinated coffee a day; the other half had to avoid coffee and other sources of caffeine. Relapses were recorded in 47% of the first group and 64% of the second: a relative risk reduction of 39%. Average consumption was approximately one cup daily.
That 39% concerns people with a specific arrhythmia, after a specific cardiac procedure. It does not extend to any “heart problem” and does not turn coffee into a therapy. However, it shows that the old advice to eliminate it automatically in the presence of atrial fibrillation deserves a little more data and a little less reflection.
The cardiac rhythm retains its complications. The trials reviewed by the AHA link coffee to a lower risk of atrial fibrillation recurrence and, at the same time, to a possible increased frequency of premature ventricular contractions, early beats that start from the lower chambers of the heart. The same drink can interact differently with different arrhythmias.
Cafestolo is not the hero of the story
In Bassetti’s post we read that the positive effects would concern traditional coffee because it preserves a natural substance called cafestol. The AHA document assigns a very different role to this compound: in clinical trials cafestol is associated with an increase in LDL cholesterol.
It is found in both caffeinated and decaffeinated coffee and is especially present in unfiltered preparations, such as espresso, French press, Turkish coffee and boiled coffee. The paper filter retains most of it, while in instant coffee the levels are very low. For those who need to control cholesterol, the preparation method can weigh more than the innocent gesture of pressing a button suggests.
The possible benefits observed probably depend on the set of compounds present in coffee and the habits of those who drink it. Cafestol, alone, can therefore leave its cloak and soundtrack to others.
Energy drinks remain out
The conclusions about coffee cannot be transferred to energy drinks. These products can concentrate a lot of caffeine in small volumes and add other substances capable of modifying its absorption and effects. The energy shot they can contain three or four times more caffeine per milliliter than normal filtered coffee.
High doses have been associated with sudden increases in blood pressure and heart rhythm disturbances, even in young adults considered to be at low cardiovascular risk. The evidence comes mostly from clinical reports and specific research remains limited, but the AHA urges avoiding high concentrations.
The new document therefore frees moderate coffee from several accusations accumulated over the years. For many adults it can remain at breakfast, during breaks and even during the day of those living with certain heart conditions, when the doctor does not identify any personal contraindications. Bassetti’s “Viva il caffè” can survive. Cafestolo, however, would do better not to take all the applause.
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