Always opt for those that do not contain stimulants and are not unnecessarily aggressive in taste. Commonly preferred are chamomile, fennel, lemon balm, fruit teas with a lower acid content, or rooibos.
This warning is general and particularly applies in practice to the long-term consumption of stronger infusions; you may encounter this phenomenon, especially in more sensitive individuals. Consider one cup of tea before bed as a completely safe approach.
The longer you steep the herb, the more substances are released into the liquid; this is a general rule. The fact is that with the duration of steeping tea leaves, not only caffeine is released into the water but also tannins, which do not neutralize the effects of caffeine but complicate its release in the body. This means that the tea will contain a lot of caffeine and tannins, and due to the presence of tannins, caffeine will be absorbed more slowly in the digestive tract, making its effects in the body more gradual and long-lasting (on the order of hours). When preparing tea, it is up to you which method you prefer concerning the goal you aim to achieve by consuming the tea.
Vitamin C is sensitive to oxidation and breaks down even at low temperatures (although decomposition increases with rising temperatures). In relation to increased temperatures, it remains stable up to 190 degrees Celsius, at which point its structure disintegrates—meaning that boiling itself does not significantly destroy it, it merely releases into the surroundings. This is advantageous in tea production, where cold brewing extracts less vitamin C than at higher temperatures.
Questions answered by
Mgr. Martin Jelinek
Lecturer and author of the educational system
Nutrition educator, lecturer, and author of the educational system and the ZOF learning application.
Mgr. Martin Jelínek has been systematically involved in nutrition education since 1999. He is the founder of ATAC, the educational company behind NutriCourses, and the author of an educational system focused on nutrition, healthy lifestyle, and the practical application of nutrition knowledge.
He graduated from the Faculty of Science at Masaryk University in Brno. Throughout his professional career, he has combined nutrition, education, and the practical application of acquired knowledge. His educational system also includes the ZOF (Zone of Optimal Functioning) learning application, where students turn theory into practical work with meal plans.
In 2007, he launched the first intake of a six-month course focused on the education of nutrition advisors. Over time, this course became the foundation for the further development of the educational system and a range of specialised courses.