Introduction:
1,3,7-trimethyl xanthine - Caffeine is the world's most consumed psychoactive drug. Adults consume 200 mg of caffeine daily. A cup of coffee accounts for 85 milligrams, making it over 2 cups per day.
Caffeine metabolism:
With a plasma half-life of about 2-12 hours, it is mainly excreted as uric acid derivatives, dimethylxanthines, and 2.4% as caffeine.
Physiological responses:
It stimulates the central nervous system and improves alertness, performance, and vigilance by activating various systems. This includes the dopaminergic system, and blocking the adenosine receptors (found to induce sleep). Optimum doses enhance activity and excitement.
Caffeine in your brew:
A scarcity of information on caffeine content in specialty coffees led to a number of studies and assessments of daily brews sold at popular coffee shops. These included Starbucks, Hampden Café, Einstein Bros, and Dunkin' Donuts. The results are mind-boggling.
The caffeine content of the same caffeine beverage (Starbucks breakfast blend) has varied from 259 mg to about 565 mg in 16 ounces purchased from the same outlet for six consecutive days. Possible factors include the type of coffee bean, roasting method, water-coffee proportion, and particle size. Evidently, highly consistent methods used in coffee preparation at specialty outlets also show huge variation.
Refrence:
By Vanaja Kholgade.
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