Caffeine metabolism

Caffeine metabolismGenetic testing and caffeine metabolism

Caffeine is a natural alkaloid and is the main ingredient of coffee. It is the most common stimulant, which also causes dependence. That’s why so many people feel they cannot function if they don’t drink their morning cup of coffee. Caffeine affects the secretion of adrenaline and thus acts as a stimulant and raises the level of energy. People who often drink coffee feel tired, weak, and have headaches if they miss their cup of coffee in the morning. Caffeine also may have other negative effects, such as increasing blood pressure. Coffee has a greater effect on people who metabolize caffeine more slowly. The reason for this is that our genetic makeup, which determines the activity of the enzyme CYP1A2, is important for the metabolism of caffeine. The aforementioned enzyme doesn’t work adequately in some people, so the daily dose of coffee has to be adapted to this deficiency.

More details about caffeine metabolism

Caffeine is one of the alkaloids with the chemical name 1,3,7-trimetilksantin. In its pure form it is a crystalline powder that has a slightly acidic flavour. It is found in over 60 plant species and in different parts of them: coffee and cacao grains, certain nuts and even tea leaves - where together with tannins they form a complex, called tein. It is a mild stimulant that has its effect on the central nervous system and the heart. In addition, it acts as a weak diuretic, meaning it speeds up the excretion of urine. It has a psychological effect (excitement, anxiety, better mood), as well as physiological (less fatigue, accelerated metabolism, increased blood pressure, greater alertness). A cup of coffee contains up to 200 mg of caffeine, a cup of tea up to 80 mg tein, and coca cola somewhere between 40 and 70 mg of caffeine. Excessive quantities of coffee can also cause unpleasant side effects such as restlessness, tremors and problems with blood pressure. One cup of coffee per day shouldn't affect our health, according to scientific research. However, we must be careful when consuming larger amounts of coffee. Because of the potentially ineffective CYP1A2 enzyme's activity, some people can have problems after 2-3 cups of coffee per day. These people are slower caffeine metabolizers, which can cause problems with high blood pressure, and can also lead to heart attack.

Process of caffeine metabolism

When we consume coffee it takes approximately 5 minutes for caffeine to be absorbed into the blood. The final effect is achieved after 30 minutes and its effect is present for a few hours. Caffeine is not accumulated in our body, but degraded, and after about 24 hours excreted from our organism. Caffeine is metabolized in the liver by the initial dimetilation process through an enzyme called cytochrome P4501A2 (CYP1A2). This enzyme is responsible for 95 percent of the metabolism process for caffeine. CYP1A2 is characterized by a high variability in its activity, which is also a consequence of differences in our genetic makeup. Therefore, changes in the DNA sequence have a significant impact on its efficiency and thus greatly determine the rate of caffeine metabolism for the individual. Replacement of the A nucleotide with a C nucleotide in a specific region within the CYPI1A2 gene results in reduced enzyme activity, which was determined by scientists through the measuring of the relationship between plasma or urine and the amount of metabolites of caffeine after consuming a certain amount of coffee.

Coffee has a stronger effect on people who have at least one C variant of CYP1A2 gene, than on the people who have two copies of a gene present in the A variant. A stronger caffeine effect is not necessarily favourable, because an ultimate effect of caffeine may be increased blood pressure. If one consumes more caffeine, or if the caffeine is present during a longer period in our system, it can considerably increase the blood pressure. Researchers have shown through several studies that people who metabolize caffeine more slowly, when ingesting large quantities of coffee, are much more susceptible to complications associated with high blood pressure and have an increased risk of heart attack. Given the results of previous research, slow caffeine metabolizers should not drink more than one cup of coffee a day.