Drinking up to five cups of caffeinated coffee a day is generally safe for most adults and may be associated with a reduced risk of several cardiovascular diseases, according to a new scientific statement from the American Heart Association (AHA).
The document was published on July 20, 2026, in the scientific journal Circulation. Its authors analyzed the results of studies on the effects of caffeine on blood pressure, cholesterol levels, heart rhythm, and the risk of stroke, coronary heart disease, heart failure, and type 2 diabetes.
For most adults, consuming up to 400 mg of caffeine per day is considered safe. This corresponds to approximately three to five standard cups of black coffee, each about 240 ml. However, the actual caffeine content can vary significantly depending on the type of coffee beans and the method of preparation.
According to the AHA, drinking two to four cups of coffee a day is associated with a lower risk of heart disease, stroke, and heart failure. In some studies, the lowest risk of coronary heart disease was observed in people who drank two to three cups a day.
Regular consumption of coffee without sugar, syrups, or cream is also associated with a reduced risk of developing type 2 diabetes. However, researchers emphasize that the benefits may be due not only to caffeine but also to other bioactive compounds in coffee that possess antioxidant and anti-inflammatory properties.
Adding large amounts of sugar, sweet syrups, cream, and other additives can reduce the beverage’s potential benefits. The authors of the review also do not recommend extending the findings about coffee to energy drinks. High doses of caffeine and the additional ingredients in energy drinks can raise blood pressure and increase the risk of heart rhythm disturbances.
The method of coffee preparation also matters. Unfiltered coffee—including espresso, French press coffee, and Turkish coffee—contains cafestol, which may contribute to an increase in levels of so-called “bad” cholesterol. When a paper filter is used, the content of this substance is significantly reduced.
However, experts do not consider five cups to be a one-size-fits-all recommendation for everyone. The response to caffeine depends on age, genetics, metabolic rate, medications taken, and overall health. For some people, even a small amount of coffee can cause a rapid heartbeat, anxiety, high blood pressure, or sleep disturbances.
Most of the data analyzed comes from observational studies, so while they show an association, they do not prove that coffee itself directly prevents disease. The American Heart Association notes the need for additional randomized controlled trials.
Source: ScienceAlert
A new study from the National University of Singapore has shown that caffeine can restore impairments in social memory following sleep deprivation by acting on a specific circuit in the hippocampus. The study was published in the journal Neuropsychopharmacology.
The scientists studied the CA2 region of the hippocampus, which is important for social memory—the ability to recognize familiar people or, in the experiment, familiar mice. In a laboratory model, after five hours of sleep deprivation, mice exhibited impaired synaptic plasticity and deficits in social memory, and caffeine helped restore these measures.
The researchers explain the effect by the fact that caffeine blocks the signaling pathways of adenosine receptors, which accumulate during wakefulness and inhibit brain activity. At the same time, the authors emphasize that their work does not concern a general “brain boost,” but rather a quite specific mechanism in a particular memory-related circuit.
As for the broader effects of coffee, literature reviews do link regular coffee consumption to a lower risk of Parkinson’s disease, while the data on Alzheimer’s disease appear less clear-cut: some reviews and meta-analyses point to a possible protective association, but the authors typically note that a causal relationship has not been definitively proven.
The authors’ main conclusion remains cautious: caffeine may temporarily mitigate certain cognitive effects of sleep deprivation, but it is no substitute for sleep. Sleep itself remains the foundation of normal memory and healthy brain function.
