Caffeine is found in varying amounts in over a hundred plants, but only coffee beans, cocoa, cola nuts and tea leaves contain a lot of it. The caffeine content in a cup of coffee is influenced by several factors:

• Roast level of the beans: more roasted (darker) beans, such as those used for espresso, produce less caffeine;
• The type of coffee used: Robusta beans contain more caffeine than Arabica beans;
• The method of preparing coffee: the less contact the coffee has with water, the less caffeine, so a cup of espresso, which is prepared in 28 seconds, contrary to popular belief, contains less caffeine.

It should be remembered that caffeine has almost no effect on the taste of coffee, so it is a mistake to associate the bitterness of coffee with the presence of caffeine in it. Bitter coffee does not mean strong, and vice versa - strong does not mean bitter! The bitter taste is given to the drink by complex organic substances - tannins. To neutralize them, milk or cream is added to coffee, they bind tannins, and the drink loses its bitterness. Caffeine is considered a moderate stimulant, affecting the central nervous system through parts of the brain.

Coffee not only invigorates a person, but also helps to overcome drowsiness. It helps to increase his working activity. The alkaloid caffeine improves reaction speed, helps to concentrate attention.

Caffeine, by stimulating the heart muscle, increases the heart's blood output, accelerates breathing and metabolism throughout the body. It promotes the dilation of blood vessels, thus improving the blood supply to all organs. At the same time, the brain vessels, on the contrary, narrow, which leads to a short-term increase in blood pressure.

Since 1958, coffee has been on the list of drinks and products recognized by the World Health Organization as safe for human health. Caffeine is completely eliminated from the body. A healthy adult can safely drink 2-3 cups of coffee a day (this is even considered a therapeutic dose for a healthy person.

  Caffeine content in food products.