Caffeine is a substance belonging to the alkaloid family, a group of compounds widespread in plants.
Caffeine, as well as the other alkaloids (atropine, nicotine, strychnine, morphine, etc.) is physiologically active on animals even at very low concentrations and is probably used by the plant as a defense mechanism from herbivores.
Caffeine (mainly extracted from coffee, Coffea arabica, Rubiaceae family), belongs to the group of purine alkaloids such as theophylline (from tea, Camellia sinensis, fam. Theaceae), and theobromine (from cocoa, Theobroma, family Sterculiaceae).
Caffeine is not only contained in coffee but is also found in other plants and foods. This is the case, for example, of coca cola, yerba mate, chocolate, Cola-based energy drinks, herbal products such as guarana, not to mention analgesics, anti-cellulite cosmetics or drugs for diseases. from cooling. It is curious to note, for example, how tea leaves have a caffeine content about double (2-4%) compared to coffee seeds (1-2%); however, due to the different extraction method, the infusion it contains approximately four times less caffeine than leachate.
Caffeine in Food
Effects of caffeine
Caffeine is the most used psychoactive drug in the world, its chemical conformation makes it suitable for interacting with specific biological receptors that regulate the functionality of the cardiovascular, endocrine and nervous systems.
The intestinal tract absorbs caffeine very quickly and plasma concentration peaks are observed after about one "hour from its ingestion. However, its metabolism is rapid and much higher than other stimulants such as amphetamines. Already 3-6 hours after" intake plasma levels of caffeine are reduced by 50%.
Being lipophilic, caffeine has the ability to quickly pass the blood-brain barrier (a kind of virtual wall present in the brain, designed to prevent the passage of many molecules carried by the blood).
Caffeine also crosses the placenta and can be present in breast milk. During pregnancy and breastfeeding it is therefore advisable to strongly reduce the intake of coffee and other foods rich in caffeine.
Although the effects of this substance are numerous (as we will see in detail in a few lines), most of them are due to the stimulating effects that caffeine exerts on the whole organism.
NERVOUS SYSTEM:
excitability, improvement of reflexes and the ability to concentrate, analgesic action,
ACTION MEDIATED BY "INTERACTION WITH BIOLOGICAL RECEPTORS (cardiovascular and respiratory system):
thanks to its action as a competitive antagonist against adenosine receptors, caffeine promotes the release of two hormones called adrenaline and noradrenaline.
Catecholamines favor the increase in body metabolism, heart rate, blood pressure and the number of respiratory acts (thus increasing blood oxygenation)
ADDITIONAL FUNCTIONS:
increased gastric acid synthesis, increased diuresis;
if applied to the skin with specific cosmetics (creams, gels and patches), it is useful in the treatment of localized adiposity.
Caffeine, sport and doping
If taken within the maximum permitted levels, caffeine has a positive effect on the performance of most athletes. Even moderate doses (200-400 mg) ingested one hour before the competition improve attention, concentration and endurance. Considering the great individual variability, it is however advisable to experiment with its use in training before taking it in competition.
An athlete tests positive for doping controls when the concentration of caffeine in his urine exceeds 0.012 mg / ml (= 12 mcg / ml). It is not easy to establish exactly what dose of intake is capable of exceeding this threshold. Generally it is recommended not to have more than 6-8 cups of espresso or two three cups of traditional coffee, in the three hours before the competition.
Caffeine and weight loss
By virtue of their high caffeine content, tea and coffee are often recommended to promote weight loss (in association with a correct diet). Several studies have confirmed this property, which finds a logical explanation in its stimulatory effect on the basal metabolism. In particular, 500 mg of caffeine (the equivalent of 5 or 6 coffees) increase the basal metabolism by 10-15%. Translated into simpler and more immediate terms, a similar level of intake allows you to consume 100-500 more calories per day ( in relation to the body size and above all to the muscle mass of the subject).
Caffeine is a characteristic ingredient of cosmetics to treat cellulite and localized adiposity; applied to the skin, it promotes the mobilization of triglycerides from the subcutaneous adipose tissue mediated by lipolytic lipase.
OTHER USEFUL INFORMATION: chewing 1-2 coffee beans helps purify the breath after a large meal. Coffee does not promote digestion, on the contrary, if taken with a lot of sugar or even worse with cream or alcohol, it slows it down. The stimulating effects some caffeine can still give the feeling of apparently better digestion.
Negative effects of caffeine
Coffee reduces the absorption and bioavailability of some substances:
riboflavin or vitamin B2
calcium (reduce consumption in the presence of osteoporosis and bone fractures)
iron
creatine
A caffeine intoxication caused by the massive intake of this substance (over 500-1000 mg in relation to individual sensitivity) causes excessive excitement, nervousness, insomnia and tachycardia
Caffeine should therefore be taken in moderation in case of:
esophagitis and gastroesophageal reflux (in addition to increasing the damaging power of gastric juices, caffeine relaxes the esophageal sphincter, a kind of valve that prevents the gastric contents from rising into the "esophagus)
stomach ulcer
anemia
hypertension
tachycardia, arrhythmias and heart problems in general
osteoporosis
Prolonged use of caffeine tends to dampen the beneficial effects seen previously and, if taken at high doses, accentuates the collateral effects (acidosis, pulmonary edema, hallucinations).
Several studies have described the presence of a mild withdrawal syndrome.
