niedziela, 15 września 2013


Coffee, tea and chocolate all naturally contain varying amounts of caffeine, while colas often have different amounts of caffeine added to them. This guide to the caffeine levels outlines how much caffeine is in each of these drinks, including decaf coffee / tea, low-caffeine drinks and caffeine-free "herbal teas" (or tisanes).

Caffeine is a bitter, white crystalline xanthine alkaloid and a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants, as well as enhancing the reward memory of pollinators. It is most commonly consumed by humans in infusions extracted from the seed of the coffee plant and the leaves of the tea bush, as well as from various foods and drinks containing products derived from the kola nut. Other sources include yerba maté, guarana berries, guayusa, and the yaupon holly.

In humans, caffeine acts as a central nervous system stimulant, temporarily warding off drowsiness and restoring alertness. It is the world's most widely consumed psychoactive drug, but unlike many other psychoactive substances, it is legal and unregulated in nearly all parts of the world. Beverages containing caffeine, such as coffee, tea, soft drinks, and energy drinks, enjoy great popularity. In North America, 90% of adults consume caffeine daily.

Part of the reason caffeine is classified by the Food and Drug Administration as GRAS (generally recognized as safe) is that toxic doses (over 1 gram for an average adult) are much higher than typically used doses (less than 500 milligrams). Ordinary consumption can have low health risks, even when carried on for years – there may be a modest protective effect against some diseases, including Parkinsons Disease, and certain types of cancer. Caffeine can have both positive and negative effects on anxiety disorders.[citation needed] Some people experience sleep disruption if they consume caffeine, especially during the evening hours, but others show little disturbance and the effect of caffeine on sleep is highly variable.

Evidence of a risk to pregnancy is equivocal, but some authorities have concluded that prudent advice is for pregnant women to limit consumption to the equivalent of two cups of coffee per day or less. The American Congress of Obstetricians and Gynecologists (ACOG) concluded in 2010 that caffeine consumption is safe up to 200 mg per day in pregnant women. Caffeine has pressor and mild diuretic effects when administered to people who are not used to it, but regular users develop a tolerance to this effect, and studies have generally failed to support the common notion that ordinary consumption contributes significantly to dehydration. With heavy use, tolerance develops rapidly to autonomic effects such as elevated heart rate and muscle twitching, but not to the cognitive or arousal effects of caffeine. The degree to which caffeine can produce clinically significant dependency and addiction remains a subject of controversy in the medical literature.

                                Type of coffee                                  
Espresso, restaurant-style
30 ml
40-75 mg
Espresso, restaurant-style, decaffeinated
30 ml
0-15 mg
Generic brewed
240 ml
95-200 mg
Generic brewed, decaffeinated
240 ml
2-12 mg
Generic instant
240 ml
27-173 mg
Generic instant, decaffeinated
240 ml
2-12 mg
McDonald's brewed
480 ml
100 mg
McDonald's Mocha Frappe
480 ml
125 mg
Starbucks Latte
480 ml
150 mg
Starbucks Pike Place brewed
480 ml
330 mg
Starbucks Pike Place brewed, decaffeinated
480 ml
25 mg

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