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What does science think about coffee?

Written by: Svenja Schindler



Time to read 3 min

We asked ourselves: How much coffee is actually healthy and why do we wake up from our midday slump after a delicious cup of coffee? We clarify conflicting information and explain the current scientific studies on the effects of coffee.

The most important facts about coffee at a glance

  • Coffee has many proven positive effects on the healthy adult body
  • Intake of up to 400 mg of caffeine daily or 2-5 cups of coffee per day is not a problem
  • Coffee is an important source of phytochemicals
  • Caffeine cannot compensate sleep deficit

What does science think about coffee?

Anyone who starts the sentence "coffee makes..." on the Internet will receive additional search suggestions such as "tired", "sick" or "nice". We find this quite confusing. However, this information on the Internet also shows that there is a lot of misinformation and contradicting information about coffee.

For many years coffee was warned of and many myths about harmful effects on health were told. However, new and recent studies say otherwise and have thoroughly improved the coffee's image. They even certify that regular, but of course not excessive, coffee consumption has a health-promoting effect.

Recent studies have shown that coffee has a similar health-promoting effect as other types of vegetables and fruits. Plant-based foods contain health-promoting phytochemicals. Coffee is a plant product and has secondary plant substances comparable to tea, vegetables or fruit, so it is no less healthy. Coffee stands out in one respect: among regular coffee drinkers, coffee is the most important dietary source of phytochemicals such as phenolic acids and polyphenols, even compared to green tea in Japan1.

A 2015 study linked high coffee consumption to a 20% lower risk of skin cancer. Specifically, the lower risk was found in participants who drank 4 or more cups of coffee per day. The protective effect appeared to increase with higher consumption, from 1 cup or less to 4 cups or more2.

What is the health-promoting amount of coffee?

For a healthy adult, an intake of up to 400 mg of caffeine is distributed throughout the day, i.e. approx. 4 cups of coffee, safe3. This corresponds to either 4 cups of coffee, 5 cups of espresso or 8 cups of black tea. Studies have shown that consuming 1 to 5 cups of coffee per day is associated with a lower mortality rate in non-smokers4.

Now in detail, the important ingredient caffeine!

Important studies show the positive effects of coffee on the human body. To better understand these studies, let's take a look at how coffee is absorbed into the body.

Coffee helps us feel more alert and focused when we wake up in the morning, before an important meeting, or after lunch. Caffeine in particular plays an important role in this. Caffeine is a natural chemical compound found in coffee and cocoa beans or tea leaves, among other things. When taken orally with caffeinated beverages or foods, it is quickly and completely absorbed by the human body. Caffeine usually takes effect 15 to 30 minutes after ingestion and can last for several hours.

Caffeine is the subject of numerous studies and has many effects on the human body. Studies have shown positive effects on attention and the speed of thought processes5. Caffeine leads to an acceleration of heart activity, metabolism and respiration. In addition, blood pressure and body temperature rise slightly. The blood vessels dilate and the blood flow to all organs increases. When tired, caffeine has a stimulating and short-term positive effect on alertness and performance. However, caffeine cannot compensate for a sleep deficit6.

Our conclusion …

The effects of coffee and caffeine are diverse and, according to many speculations, not harmful to health. According to the precautionary principle, current science recommends a maximum intake of around 400 mg caffeine daily or consider 2-5 cups of coffee a day to be unproblematic6.