HIGH ENERGY DRINKS
Generally high energy drinks include methylxanthines (including caffeine), B vitamins, and herbs. Other common ingredients in high energy drinks are guarana (see below), which has a natural high caffeine content, taurine, plus various forms of ginseng, maltodextrin, Carbonated water, inositol, carnitine, creatine, glucuronolactone and ginkgo biloba. Some contain high levels of sugar, and many brands also offer artificially-sweetened diet or low carb versions.
The central ingredient in most energy drinks is caffeine, the same stimulant found in coffee or tea, often in the form of guarana or yerba mate. The average 237 milliliter (8 fluid ounce) energy drink has about 80 mg of caffeine, with 480 ml (16 fl. oz.) drinks containing around 150 mg, although more recently, drinks containing as much as 400 mg of caffeine have been marketed.
HISTORY OF GUARANA
The word guarana comes from the Portuguese guaraná, which has its origins in the Satere-Maue word for the plant, warana.
Guarana plays an important role in Tupi and Guarani Brazilian culture. According to a myth attributed to the Sateré-Maué tribe, guarana's domestication originated with a diety killing a beloved village child. In order to console the villagers, a more benevolent god plucked the left eye from the child and planted it in the forest, resulting in the wild variety of guarana. The god then plucked the right eye from the child and planted it in the village, giving rise to domesticated guarana.
The Guaranís would make a tea by shelling and washing the seeds, followed by pounding them into a fine powder. The powder is kneaded into a dough and then shaped into cylinders. This product is known as guarana bread or Brazilia coke, which would be grated and then immersed into hot water along with sugar.
As guarana is rich in caffeine, it is of interest for its potential effects on cognition. In rats, guarana increased memory retention and physical endurance when compared with a placebo
A 2007 human pilot study assessed acute behavioral effects to four doses (37.5 mg, 75 mg, 150 mg and 300 mg) of guarana extract. Memory, alertness and mood were increased by the two lower doses, confirming previous results of cognitive improvement following 75 mg guarana.