What does science think about coffee?
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 contradictory 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
- An 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 secondary plant substances
- Caffeine cannot compensate for sleep deficit
What does science think about coffee?
If you enter the beginning of the sentence “Coffee makes…” on the Internet, you will receive additional search suggestions such as “tired”, “sick”, or “beautiful”. We find this quite confusing. However, this information on the Internet also shows that there is a lot of misinformation and contradictory advice about coffee.
There have been warnings about coffee for many years and many myths about harmful health effects have been told. However, new and recent studies say otherwise and have thoroughly improved coffee's image. They even attest that regular, but of course not excessive coffee consumption has health-promoting effects.
Recent studies have shown that coffee has a similar health-promoting effect as other vegetables and fruits. Plant-based foods contain health-promoting secondary plant substances. Coffee is a plant-based product and has comparable phytochemicals to tea, vegetables or fruit, so it is no less healthy. Coffee stands out in one respect: among people who drink coffee regularly, 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 or fewer cups to 4 cups of coffee or more2.
What is the health-promoting amount of coffee?
For a healthy adult, up to 400 mg of caffeine is consumed 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 lower mortality rates among non-smokers4.
Now in detail, the important ingredient caffeine!
Important studies prove 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.
When we get up in the morning, before an important meeting or after lunch, coffee helps us feel more awake and focused. Caffeine in particular plays an important role. Caffeine is a natural chemical compound that occurs, among other things, in coffee and cocoa beans or tea leaves. When drinks or foods containing caffeine are taken orally, it is quickly and completely absorbed by the human body. The effects of caffeine usually begin 15 to 30 minutes after ingestion and can last for several hours.
Caffeine has been 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 cardiac activity, metabolism and breathing. In addition, blood pressure and body temperature increase slightly. The blood vessels expand and blood flow to all organs increases. When you are tired, caffeine has a stimulating and short-term positive effect on your state of 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, are not harmful to health. According to the precautionary principle, current science recommends a maximum intake of around 400 mg of caffeine daily or consider 2-5 cups of coffee per day to be unproblematic6.
