According to Chinese legend, the Chinese emperor Shennong, reputed to have reigned in about 3000 BCE, inadvertently discovered tea when he noted that when certain leaves fell into boiling water, a fragrant and restorative drink resulted. [247] Shennong is also mentioned in Lu Yu's Cha Jing, a famous early work on the subject of tea. [248] Shen JG, Brooks MB, Cincotta J, Manjourides JD (February 2019). "Establishing a relationship between the effect of caffein

Theobromine (12%): Dilates blood vessels and increases urine volume. Theobromine is also the principal alkaloid in the cocoa bean ( chocolate). Both the time it took all three groups to fall asleep and the time they spent awake at night increased significantly ( 18).One large study looked at the effects of high caffeine intake on incontinence in more than 65,000 women without incontinence.

Caffeine is excreted into breast milk. Consult with your health care provider about the risks of using caffeine while you are breast-feeding. Caffeine may cause side effects in your baby. Interestingly, cortisol levels were similar between regular and less frequent caffeine consumers, suggesting the compound may have the same effect on stress levels regardless of whether you drink it habitually ( 12). Caffeine is also a common ingredient of soft drinks, such as cola, originally prepared from kola nuts. Soft drinks typically contain 0 to 55 milligrams of caffeine per 12 ounce (350mL) serving. [232] By contrast, energy drinks, such as Red Bull, can start at 80 milligrams of caffeine per serving. The caffeine in these drinks either originates from the ingredients used or is an additive derived from the product of decaffeination or from chemical synthesis. Guarana, a prime ingredient of energy drinks, contains large amounts of caffeine with small amounts of theobromine and theophylline in a naturally occurring slow-release excipient. [233] Other beverages Some beverages combine alcohol with caffeine to create a caffeinated alcoholic drink. The stimulant effects of caffeine may mask the depressant effects of alcohol, potentially reducing the user's awareness of their level of intoxication. Such beverages have been the subject of bans due to safety concerns. In particular, the United States Food and Drug Administration has classified caffeine added to malt liquor beverages as an "unsafe food additive". [246]Be aware that ‘legal highs’ and controlled drugs often contain caffeine. This is a problem as you do not know how much caffeine you are taking, and it could also increase the harms of some. One study of 6 ‘legal high’ products found that some contained around 90% caffeine. This means that taking one gram of the product would be like taking around 13 litres of cola, 3.75 litres of energy drink, or 12-15 cups of coffee. A detailed review suggests that although caffeine triggers certain brain chemicals similarly to the way cocaine and amphetamines do, it does not cause classic addiction the way these drugs do ( 30). This is more likely to cause side effects, as a full key down/key up is generated. It's included for compatibility with older systems which might need this The average cup of coffee contains 150-200 milligrams (mg) of caffeine per cup, while a cup of tea will have about 60 mg of caffeine. Cola products have about 30-40 mg of caffeine, and most energy drinks have about 60-70 mg. Be sure to account for any dietary caffeine that is consumed.