Caffeine - Should We Be Careful?

Caffeine and its psychostimulant effects have been known to mankind for many centuries. It is because of this effect, it is consumed today all over the world in the form of one or another drink. It is mostly isolated from the leaves and beans of coffee, but is also found in tea and cocoa, as well as in a number of other plants. It, as well as its derivatives such as theophylline and theobromine, are also introduced into a variety of energy drinks.

It is the subject of many years of research on the mechanism of its action, its effect on health, the impact on drug metabolism and more. Unlike other psychoactive substances, reasonable consumption is considered safe and its content in food and beverages is not observed by law.
As already mentioned, caffeine is a stimulant of the central nervous system. Consumed through coffee, tea or energy drinks, it keeps a person awake, increases his efficiency, allows the thought to flow quickly and smoothly, increases the overall tone.

Normally, up to 45 minutes after consumption, it is completely absorbed from the gastrointestinal tract, and the elimination half-life is about 3-4 hours. The latter is significantly affected by the use of drugs - such as oral contraceptives, diseases such as those leading to liver failure, or certain physiological conditions such as pregnancy. In these cases, its elimination from the body is delayed to one degree or another and its consumption should be reduced. On the contrary - in heavy smokers, its level decreases rapidly.

Caffeine itself is a competitive inhibitor of adenosine, including its receptors in nervous tissue. Inhibition of adenosine leads to increased levels of the neurotransmitters dopamine, adrenaline, noradrenaline, serotonin. They stimulate the sympathetic nervous system - increase heart rate, blood pressure, blood flow to muscles and restrict it to the skin and internal organs, raise blood sugar, and serotonin causes positive mood swings. By altering the activation of some enzymes, on the other hand, caffeine alters the metabolism of some adrenaline-like drugs (ephedrine) such as amphetamines, methamphetamines and methylphenidate, and others.

Other effects of the alkaloid are renal vasodilation and increased glomerular filtration, respectively, and diuresis. Caffeine also activates proton pumps in the cells that produce hydrochloric acid in the stomach and raises the pH of its contents.
It is also used in medical practice in the fight against physical fatigue, unusual weakness or drowsiness. It is often used in combination with medicines to potentiate their effects, such as analgesics or ergotamine, used for migraines, as well as to eliminate the side effects of antihistamines prescribed for allergies.

The main reason to consume coffee, tea, cola or energy drinks is to overcome fatigue and maintain our ability to work for longer. However, everyone has a different sensitivity to the effects of caffeine, which depends on both the body and the person's habits in consuming such products. The average content of caffeine in a cup of coffee is between 40 and 85 mg, depending on the method of preparation, for a cup of tea - between 20 and 40 mg for different types, and in cocoa-containing beverage - less than 10.

Many people are considered addicted and not they can start the day without the morning dose of coffee, and at any sign of fatigue they also reach for it. Others simply enjoy its taste, its aroma, or its consumption becomes a habit, but not a necessity.

Whether or not addiction can be debated for a long time, but there is definitely tolerance as well as a withdrawal effect. It has been proven that regular intake of caffeine in one form or another leads to adaptation of the body by increasing the number of adenosine receptors and increasing their sensitivity. This on the one hand reduces the effect of caffeine, and on the other hand when the sudden cessation of its consumption, the body is under the high influence of adenosine, which is expressed in certain symptoms.

Tolerance develops quickly in people who seriously consume coffee, for example - about 400 mg of caffeine three times a day for about a week are enough. Headache and nausea due to dilatation of the vessels of the brain, irritability, difficulty concentrating, fatigue, drowsiness, due to reduced levels of catecholamines, even depression at lower levels have been reported when stopping daily consumption (the most common regular form of caffeine intake). of serotonin. Decreased stomach acidity manifests itself as stomach pain. Some of the complaints occur in the first 24 hours, reach their maximum by the 48th and last up to five days until the level of adenosine receptors in the brain normalizes - the increase of which is the main reason for the described phenomenon of withdrawal.

What is the effect of caffeine on memory and performance? Clinical trials have found that taking 100 mg of caffeine causes a change in the activity of areas in the frontal lobe of the brain responsible for working memory, as well as the frontal cingulum, an area of ​​the brain that controls attention and concentration. The opposite is true of short-term memory and causes the phenomenon of 'on the tip of the tongue' to occur frequently.

There is much debate about the place of caffeine in heart disease, and more specifically, coronary heart disease. However, a number of clinical studies have shown no link between them. Some protection has been reported in caffeine users regarding coronary heart disease, but not in hypertensive patients. The only effects on the cardiovascular system are a momentary increase in heart rate, in some cases arrhythmias perceived by the patient as skipping, or a certain increase in blood pressure. They are more common when consuming energy drinks, as well as people who do not regularly use caffeine-containing products. They occur depending on the sensitivity of each organism.
Another association often made with caffeine is bone loss. There is no clinical evidence that moderate intake of the alkaloid (up to 300 mg per day), most often through coffee and tea in postmanopausal women, can cause osteoporosis, especially in the presence of adequate calcium-containing foods in the diet.

Caffeine is often added to weight loss products. Its role in these cases is to increase catecholamines, increase energy expenditure and suppress appetite, as well as lipolytic of one of its products - paraxanthine. However, the clinical significance for weight loss is insignificant. The safety and efficacy of caffeinated products for this purpose are usually unproven.

The consumption of caffeinated beverages during pregnancy occupies a special place. There is no evidence that they can harm the fetus or cause premature birth. However, experts warn that during this period it is desirable for a woman not to overdo it and to limit herself to a maximum of two cups of coffee a day. Moreover - it has already been said that its elimination during pregnancy is delayed 2-3 times.

What about caffeinated beverages and their consumption in children? In the first place here comes the problem of replacing useful and nutritious products with unsuitable for growing organisms soft drinks. On the other hand, caffeine in children causes changes in behavior such as restlessness, overactivity and violentness, often combined with difficulty concentrating. The described withdrawal phenomena are also observed in them, even with minimal intake of caffeine every day (less than 30 mg).

Caffeine overconsumption, especially for a short period of time, can cause the so-called. "Caffeine". It includes nervousness, irritability, anxiety, muscle twitching and tremor, insomnia, headache, palpitations. Regular overuse can also lead to gastroesophageal reflux disease, gastric ulcers, erosive gastritis.
Caffeine intoxications have also been reported, most commonly through the intake of pure caffeine through the nose, similar to drugs. It manifests itself in agitation, tremor, arrhythmias, disturbance of the thought process, increased diuresis and gastrointestinal problems. The lethal dose of caffeine for humans is between 150 and 200 mg / kg body weight, equivalent to about a single intake of 80-100 coffees. It is difficult to die through coffee, but it is possible to abuse caffeine tablets, causing ventricular fibrillation.

As a pleasure, habit or necessity, caffeine is part of the daily lives of many people, whether the choice is coffee, tea, chocolate or energy drink. How the body absorbs it is a matter of sensitivity, intake regime, body weight, but also stress factors. In moderation, it should not cause any harm. However, if the daily intake is over 500-600 mg, complaints will occur. In these cases, as well as in severe hypersensitivity, it is desirable to limit or avoid caffeine-containing products in the presence of sleep problems.