Caffeine: benefits, dosage, contraindications
Other name(s)
1,3,7-trimethylxanthine or methyltheobromine
Scientific name(s)
1,3,7-trimethylxanthine
Family or group:
Phytochemicals
Indications
Scoring methodology
EFSA approval.
Migraine ✪✪✪✪✪
Oral intake of 100 to 260 mg of caffeine in combination with 500 to 2,000 mg of acetaminophen, 500 mg of aspirin, and/or 50 to 100 mg of sumatriptan is effective for treating migraines. Some evidence shows that caffeine combined with aspirin and acetaminophen may be more effective than sumatriptan for treating a migraine attack. Oral caffeine in combination with analgesics is approved by the United States Food and Drug Administration (FDA) to treat migraines and tension-type headaches.
Posologie
Oral
100 - 250 mg
Oral sumatriptan for acute migraine.
Treatment of menstruation-associated migraine with the nonprescription combination of acetaminophen, aspirin, and caffeine: results from three randomized, placebo-controlled studies.
Efficacy and safety of acetaminophen, aspirin, and caffeine in alleviating migraine headache pain: three double-blind, randomized, placebo-controlled trials.
reatment of severe, disabling migraine attacks in an over-the-counter population of migraine sufferers: results from three randomized, placebo-controlled studies of the combination of acetaminophen, aspirin, and caffeine.
Concentration ✪✪✪✪✪
The consumption of 100 to 600 mg of caffeine can improve alertness after prolonged sleep deprivation, but generally does not affect mental performance or accuracy. Drinking coffee containing 100 mg of caffeine before a cognitive performance test improves reaction time in people who have recently had poor-quality sleep and in those with adequate sleep.nn
Posologie
Oral
100 - 600 mg
The effects of L-theanine, caffeine and their combination on cognition and mood.
The effects of a low dose of caffeine on cognitive performance.
The effects of black tea and other beverages on aspects of cognition and psychomotor performance.
Influence of caffeine ingestion on perceived mood states, concentration, and arousal levels during a 75-min university lecture.
Type 2 Diabetes ✪✪✪✪✪
Consumption of caffeine from beverages such as coffee or tea is associated with a lower risk of developing type 2 diabetes. This effect is dose-dependent.nnFurthermore, it is not known whether caffeine is beneficial in adults with diabetes. A few small studies show that caffeine consumption may further reduce insulin sensitivity in patients with type 2 diabetes, gestational diabetes, or in subjects at risk of developing diabetes.nn
Posologie
Oral
200 - 500 mg
Caffeinated and decaffeinated coffee consumption and risk of type 2 diabetes: a systematic review and a dose-response meta-analysis.
The relationship between green tea and total caffeine intake and risk for self-reported type 2 diabetes among Japanese adults.
Coffee and tea consumption and risk of type 2 diabetes.
Does long-term coffee intake reduce type 2 diabetes mellitus risk?
Hypotension ✪✪✪✪✪
Preliminary clinical research shows that the consumption of beverages containing caffeine increases blood pressure in elderly people with postprandial hypotension. nn
Posologie
Oral administration
Memory ✪✪✪✪✪
A single oral dose of 65 to 200 mg of caffeine per day appears to improve memory in some people, such as students and those with an extroverted personality. nn
Posologie
Oral administration
65 - 200 mg
Obesity ✪✪✪✪✪
Caffeine combined with ephedrine appears to promote loss of fat mass when intake is accompanied by a low-fat diet and physical exercise. Indeed, taking 192 mg of caffeine in combination with 20 to 90 mg per day of ephedra for 6 months appears to cause a slight weight loss (5.3 kg) in people with a body mass index between 25 and 40 kg/m. nn
Posologie
Oral administration
192 mg
Randomised comparison of diets for maintaining obese subjects' weight after major weight loss: ad lib, low fat, high carbohydrate diet v fixed energy intake.
The acute and chronic effects of ephedrine/caffeine mixtures on energy expenditure and glucose metabolism in humans.
Sports performance ✪✪✪✪✪
Caffeine stimulates muscular power, adrenaline, blood flow, and heart rate. It thus enhances sports performance. Caffeine is one of the most commonly used stimulants by athletes. Caffeine consumption is permitted by the National Collegiate Athletic Association (NCAA) within certain limits. Urine concentrations above 15 mcg/mL are prohibited in competition. It takes 500 mg of caffeine, about 6 to 8 cups of coffee consumed 2 to 3 hours before competition, for most people to reach this urine concentration.
Posologie
Oral
3 - 6 mg/kg
Effect Of Ambient Temperature On Caffeine Ergogenicity During Endurance Exercise
Metabolic Effects Of Caffeine Ingestion And Physical Work In 75-year Old Citizens. A Randomized, Double-blind, Placebo-controlled, Cross-over Study
The Influence Of A CYP1A2 Polymorphism On The Ergogenic Effects Of Caffeine
Asthma ✪✪✪✪✪
Caffeine supplementation appears to improve respiratory function in cases of mild to moderate asthma for up to 4 hours.
Posologie
Oral
9 mg/kg
Parkinson's disease ✪✪✪✪✪
It is not clear whether caffeine improves certain symptoms of Parkinson's disease, because clinical research results are conflicting. A large retrospective study found that caffeine consumption greater than 300 mg per day for 18 months in combination with dopaminergic treatment did not slow the progression of Parkinson's disease. Furthermore, caffeine does not appear to be useful in reducing the risk of tardive dyskinesia. In addition, large-scale epidemiological studies have shown that people who consume caffeine-containing beverages, such as coffee, tea, and cola, have a lower risk of developing Parkinson's disease. Indeed, men consuming 3 to 4 cups of caffeinated coffee per day, equivalent to 421 to 2,716 mg of total caffeine, appear to have the lowest risk of developing this disease.
Posologie
Oral administration
124 - 2716 mg
Fatigue ✪✪✪✪✪
During physical exercise, athletes experienced less physical fatigue with caffeine supplementation. In addition, clinical research has shown that consuming 500 ml of an energy drink providing 1 gram of taurine and other ingredients, including caffeine and B vitamins, reduces exercise-related fatigue. It is possible that this effect is due to the combination of ingredients rather than taurine alone.
Posologie
Oral administration
240 - 300 mg
Synergies
Properties
Cardiovascular
Caffeine can influence cardiovascular reactivity to stress, either by enhancing the stress response itself or by increasing the response during stress. Caffeine can cause a slight decrease in heart rate after consumption and appears to increase blood pressure. This effect is probably due to the vasoconstrictive action of caffeine and to inhibition of adenosine receptors and adenosine-induced vasodilation. Moreover, large amounts of caffeine, greater than 10 mg/kg/day, can cause tachycardia and premature ventricular contractions. However, clinical research shows that long-term caffeine consumption leads to a reduction in its effects on blood pressure over time.
Usages associés
Neurological
Caffeine stimulates the central nervous system (CNS), the heart, the muscles and possibly the pressor centers that control blood pressure. Possible mechanisms include blockade of adenosine receptors and inhibition of phosphodiesterase. Caffeine reduces cerebral blood flow by vasoconstriction due to blockade of adenosine receptors. By blocking adenosine receptors (A1 and A2), caffeine can induce dopamine release and produce stimulant effects on the CNS. The stimulant effects of caffeine on the CNS are thought to improve alertness and psychomotor performance. On the other hand, caffeine may protect the brain's dopaminergic neurons from degeneration and prevent Parkinson's disease. This effect appears to be related to modulation of adenosine receptors.
Usages associés
Digestive effect
Caffeine increases the secretion of gastric acid, which facilitates digestion.
Metabolic
Some clinical evidence shows that acute caffeine consumption causes a dose-dependent increase in plasma levels of free fatty acids and ketones, 4 hours after ingestion.
Usages associés
Respiratory effect
Caffeine has been used to combat respiratory disorders such as asthma and neonatal apnea. Indeed, caffeine decreases airway resistance and stimulates breathing via blockade of adenosine receptors and inhibition of phosphodiesterase. In addition, it stimulates the respiratory center of the brain, increases the responsiveness of peripheral chemoreceptors to carbon dioxide, and increases diaphragmatic activity. Caffeine also reduces fatigue of the respiratory muscles.
Analgesic
Caffeine blocks pain mediators, such as adenosine receptors, and the activity of certain enzymes, notably cyclooxygenase-2.
Usages associés
Anti-inflammatory
The effects of caffeine on the inflammatory response are contradictory. In healthy adults, a single dose of caffeine reduced plasma markers of inflammation. In theory, caffeine may have anti-inflammatory effects by inhibiting phosphodiesterases. However, clinical research in preterm infants suggests that serum caffeine levels ≥ 20 mcg/mL are associated with a pro-inflammatory state with increased cytokines.
Effect on fertility
Caffeine slows the breakdown of cyclic AMP in cells and increases sperm motility and longevity.
Safe dosage
Adults aged 18 years and older: 400 mg
Daily caffeine intake of 400 mg is not associated with significant cardiovascular, bone, behavioral, or reproductive adverse effects in healthy adults, nor with an increased risk of major chronic diseases such as cardiovascular disease. This amount of caffeine is similar to the amount of caffeine found in about 4 cups of coffee. Acute use of high doses, generally exceeding 400 mg per day, has been associated with significant adverse effects such as tachyarrhythmias and sleep disturbances. Chronic consumption, especially in large amounts, can lead to tolerance, habituation, psychological dependence, and other adverse effects.
Interactions
Médicaments
Adenosine : moderate interaction
Caffeine is a competitive inhibitor of adenosine and may reduce its vasodilatory effect in humans.
Antiplatelet agents/Anticoagulant : moderate interaction
Caffeine appears to have antiplatelet properties. Its concomitant use with medications of this type could increase the risk of bleeding.
Antidiabetic : minor interaction
Caffeine may have blood glucose-modulating properties and interfere with the effects of antidiabetic medications.
Carbamazepine : moderate interaction
Caffeine intake may reduce the anticonvulsant effect of carbamazepine and increase the risk of epileptic seizures.
Cimetidine : moderate interaction
Cimetidine reduces the elimination of caffeine and could promote its accumulation in the blood.
Oral contraceptives : minor interaction
Contraceptives slow the elimination of caffeine and increase its adverse effects.
Cytochrome P450 substrate : minor interaction
Caffeine is metabolized by CYP1A2. Theoretically, drugs that inhibit CYP1A2 may decrease the clearance rate of caffeine and increase caffeine levels.
Diuretics : moderate interaction
The diuretic effects of caffeine could add to those of substances that already have this property.
Ephedrine : strong interaction
The combination of caffeine and ephedrine carries serious risks of hypertension, seizures, and cardiac arrest.
Plantes ou autres actifs
Caffeine: moderate interaction
Co-administration of caffeine and melatonin can increase melatonin levels by approximately 142%; this effect is more pronounced in non-smokers.
Caffeine: moderate interaction
Caffeine has a diuretic effect. If stopped abruptly, this could alter lithium clearance and increase its side effects.
Precautions
Pregnant women aged 18 years and older: use with caution
Caffeine intake should be monitored during pregnancy because caffeine crosses the human placenta, but it is not considered teratogenic and fetal blood and tissue levels are similar to maternal concentrations. Moderate consumption has not been associated with clinically significant fetal adverse effects. Caffeine intake should be kept below 300 mg per day during pregnancy. This is similar to the amount of caffeine contained in about 3 cups of coffee or tea.
Children: use with caution
Daily caffeine consumption at doses below 2.5 mg/kg per day is not associated with significant adverse effects in children and adolescents.
Breastfeeding women: use with caution
When used orally in large amounts, it can have negative effects on the infant of a breastfeeding woman. Caffeine is excreted slowly in infants and can accumulate. Caffeine may cause sleep disturbances, irritability, and increased intestinal activity in breastfed infants exposed to caffeine.
Contraindications
Allergies : prohibited
Do not use in people allergic to caffeine.
