One filter coffee for breakfast, two more in the office, an espresso after noon and at 4 pm a cappuccino: statistically speaking, every adult in Germany drinks around 162 liters of coffee a year. Researchers have argued for years how healthy the black broth is. Recently, several studies indicated that moderate coffee consumption can even have a positive effect on health. But what is moderate?

Australian researchers now want to have found an answer to that: According to less than six cups of filter coffee per day harmless, at least when it comes to the risk of cardiovascular disease, they report in the journal "The American Journal of Clinical Nutrition".

The researchers had evaluated data from more than 347,000 people aged between 37 and 73 years, who are stored in a biobank in the UK. It contains information about dietary habits, diseases and the genome of the subjects. Participation in the study was voluntary.

From six cups of coffee increases the risk

Using the information, researchers from the University of South Australia investigated whether coffee consumption and hypertension are related. High blood pressure is considered a risk factor for many diseases such as heart attacks, heart failure and strokes. The most important findings:

  • Compared to people who drank one to two cups of coffee a day, non-coffee drinkers had an eleven percent higher risk of cardiovascular disease. That supports previous studies, which indicate that coffee could even be beneficial to health.
  • Those who drank decaffeinated coffee had an average seven percent higher risk.
  • However, from six cups of coffee per day, the risk of cardiovascular disease increased dramatically, averaging 22 percent.

"Based on our data, six cups were the turning point from which caffeine increases the risk of cardiovascular disease," says study author and epidemiologist Elina Hyppönen. Those who want to protect their heart and avoid high blood pressure should therefore drink less than six cups of coffee a day. From the data, however, it is not clear how big the cups were and in what way the coffee was prepared.

The (bio) chemistry in the food

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Even if the higher risk of cardiovascular disease is due solely to coffee consumption, the study does not answer. There are many factors that can favor the diseases. It is therefore almost impossible to attribute a heart attack to excessive coffee consumption, no matter how large the data base is.

It would be conceivable, for example, that just those who drink a lot of coffee, who have a lot of stress, little sleep and thus become ill. With the coffee, the disease would have nothing to do then.

In the end, coffee is the same as many things in life, argues Hypponen. "If you overdo it, your health will pay for it."