Categories
Uncategorized

Caffeine

Coffee and tea are among the most popular beverages in the world and contain significant amounts of caffeine.
Caffeine is the most widely consumed psychoactive agent.
Caffeine is consumed regularly by over 80% of the US population.
The average daily caffeine intake in the US is about 186-226 mg/D, well below the very conservative limit of 400 mg per day cited in safety reviews.
Many plants contain caffeine in their seeds, fruits, and leaves: Cacao beans yerba matte leaves, and guarana berries.
85% of adults consume caffeine daily, and an average caffeine intake is 135 mg per day, equivalent to about 1 1/2 standard cups of coffee.
Coffee is the predominant source of caffeine ingested by adults, whereas soft drinks and tea and more important sources of caffeine ingested by adolescents.

1,3,7-trimethylxanthine, a natural purine alkaloid.

An adenosine receptor antagonist, that accounts for its stimulant action.

Caffiene molecular structure is similar to adenosine, and allows it to bind to adenosine receptors, block adenosine, and inhibit its effects.

The cumulation of adenosine in the brain inhibits arousal and increases drowsiness, and in moderate doses caffeine can antagonize the effects of adenosine and reduce fatigue, increase alertness and reduce reaction time.

Caffeine improves vigilance during tasks of long duration such as working on an assembly line or long distance driving and flying aircraft.
Caffiene cannot compensate for the decline in performance after long-term sleep deprivation, but its mental benefits are most pronounced in sleep deprived states.
Caffeine consumption later in the day can increase sleep latency and reduce the quality of sleep.
Caffeine can induce anxiety, particularly in doses of 200 mg or greater, and  in sensitive persons including those with anxiety or bipolar disorders.

It spreads throughout the body and crosses the blood-brain barrier.

A stimulant that can influence neuronal control pathways in the central and peripheral nervous systems.

A bio-active ingredient found in commonly consumed beverages such as coffee, tea, and sodas.

Short-term physiological effects of caffeine include increased blood pressure and sympathetic nerve outflow.

It is safe in the low-dose and moderate dose is present in beverages.

In excessive doses it can be harmful.

Can be synthesized and added to foods and beverages including soft drinks, energy drinks, energy shots and to tablets market for reducing fatigue.
It is widely used for treatment for apnea of prematurity in infants and caffeine and analgesic agents are used together in pain medications.

Caffeine intake can contribute to pain relief when added to analgesic agents.

Habitual consumption of caffeine may inhibit physiological short-term effects.

Caffeine is known to shortly increase blood pressure, whereas long term consumption could decrease blood pressure.

Consumption of caffeine increases parasympathetic activity in habitual caffeine consumers.

Capable of increasing work capacity while individuals perform strenuous tasks, likely due to caffeine’s ability to increase sympathetic nerve outflow.

Has tendency to inhibit parasympathetic activity in non-habitual consumers.

The parasympathetic activity increases in the supine position.

Caffeine may influence autonomic activity differently for individuals who are more active or elderly.

Probably most frequently consumed drug in the world.

Most frequently ingested psychoactive substance.

Approximately 80% of caffeine consumed is in the form of coffee.

Common beverages coffee, tea, soft drinks, cocoa, chocolate containing foods, pain medications, and stimulants are important sources.

For typical servings caffeine content is highest in coffee, energy drinks, and caffeine tablets, intermediate in tea, and lowest in soft drinks.

Energy drinks contain between 70 and 200 mg of caffeine per 16 ounce serving.

An 8 ounce cup of coffee contains 110-150 mg for drip, 65-125 mg for percolated, and 40-80 mg for instant coffee.

Soft drinks contain 10-16 mg per 100 gm, coffee 35-75 mg per 100 gm and black tea contains about 22 mg per 100 gm.

Caffeinated beverages contain 50-100 mg of caffeine.

An ergogenic compound that raises heart rate and blood pressure.

Has short term cardiovascular effects, including increased plasma renin levels, peripheral vasoconstriction, increased blood pressure, and cardiac

arrhythmias.

A bio-active ingredient found in commonly consumed beverages such as coffee, tea, and sodas.

Short-term physiological effects of caffeine include increased blood pressure and sympathetic nerve outflow.

Habitual consumption of caffeine may inhibit physiological short-term effects.

Consumption of caffeine increases parasympathetic activity in habitual caffeine consumers.

Capable of increasing work capacity while individuals perform strenuous tasks, likely due to caffeine’s ability to increase sympathetic nerve outflow.

Has tendency to inhibit parasympathetic activity in non-habitual consumers.

The effects on parasympathetic activity may vary depending on the position of the individual when autonomic responses are measured.

The seated position inhibits autonomic activity after caffeine consumption, explaining why some caffeine consumers do not experience short-term effects of caffeine if their routine requires many hours in a seated position.

Binds to the adenosine class of G protein coupled receptors on the heart muscle surface, which begins a second messenger system in the cyclic adenosine monophosphate system inside the cells and mimics epinephrine (Piirainen H at al).

Increases the rate of glycolysis, which increases ATP available for muscle contraction and relaxation and can cause positive Inotropy and chronotropy, with an associated stronger and faster heartbeat.

Exposure increases blood pressure and prayerful vascular resistance immediately, in part because of sympathetic stimulation.

It is metabolized by cytochrome P-450, especially CYP1A2.
Caffeine metabolites include: paraxanthine, theophylline and theobromine, which are further metabolized to uric acid and eventually is excreted with urine.
The half-life of caffeine in adults is 2.5-4.5 hours, but there is large variation from person to person.
The half-life in newborns is about 80 hours due to limited capacity to metabolize caffeine.
The capacity for caffeine metabolism per kilogram of body weight remain stable after 5-6 months of age.
Smoking accelerates caffeine metabolism, reducing the half life by 50%, whereas oral contraceptive use doubles the half-life of caffeine.
Pregnancy reduces caffeine metabolism, especially in the third trimester, when half life of caffeine can be up to 15 hours.
Metabolizing enzymes of caffiene is a partly inherited manifestation.
Some individuals have genetically determined slower caffeine metabolism and compensate by having lower habitual caffeine intake than persons without this genetic predisposition.
Medications including quinolone antibiotics, cardiovascular drugs, bronchodilators, and anti-depressant agents can slow caffeine clearance and increase its half-life, because they are metabolized by the same liver enzymes.
Caffeine, alternatively can affect the action of various drugs.

A variant in the gene encoding CYP1A2 is associated with higher plasma caffeine levels and a lower ratio paraxanthine to caffeine and a lower caffeine intake

May increase arterial stiffness.

May increase urine output.

No association between caffeine consumption and breast cancer risk (Ishitani).

Coffee intake is associated with a lower incidence of diabetes and favorable effects on the endothelial function.

Consumption associated with better mood in women (Kawachi I).

Inverse association between coffee drinking and depression and suicide.

Adverse effects manifest with ingestion with doses higher than 200 mg of caffeine and is associated with insomnia, nervousness, headache, tachycardia, arrhythmias, and nausea.

Meta-analyses show the consumption of caffeine does not demonstrate association with ventricular premature contractions or ventricular arrhythmias.

In a random clinical trial short term affects of high does caffeine in patients with heart failure at increased risk for arrhythmic events showed no significant effect on the frequency of ventricular or superventricular ectopies even doing physical stress or a treadmill test (Zuchinali P et al).

The above study challenges the perception that caffeine intake should be limited in patients with heart disease at risk for arrhythmia.

It is an effective ergogenic aid for endurance in athletes.

It is on the list of banned substances by the International Olympic Committee.

Oral absorption is rapid waves peak plasma concentrations after 29.8 minutes.

Mobilizes fat stores and stimulates muscles to use fat delaying depletion of muscle glycogen and allows for prolonged exercise (Laurent D et al).

Has essentially complete bioavailability with oral intake and a plasma half-life varying from 2.7-9.9 hours ( Blanchard J).

In a longitudinal study of 50,739 US women with a mean age of 63 years free of depression and followed, the depression risk decreased with increasing caffeinated coffee consumption (Lucas M et al).

Caffeine containing products have a great association with severe adverse events compared with non-caffeine containing products.
Caffeine containing products can be divided into 4 categories: energy products, pre-workout products, coffee, tea, or soda, and weight loss products.
The caffeinated products most likely to be associated with the most severe adverse events including death were caffeine containing pre-workout and weight loss products.
 
More females are identified with caffeine adverse events.
Caffeine containing products including multi ingredient pre-workout supplements, energy products, and weight loss products or common sources of caffeine.
These caffeine containing products increase energy, metabolic activity, and alertness, while reducing sensations of tea or hunger.
Caffiene containing products contain labels stealing Concentrations, ranging from 60-400 mg per serving: discrepancies exist however from the true caffeine content as labeled.
Energy drinks tend to primarily contain caffeine, vitamins, herbs and amino acids.
High concentration of caffeine in these products makes them more susceptible to misuse.

Leave a Reply

Your email address will not be published. Required fields are marked *