Energy Drinks

               Energy drinks are considered to be beverages that contain caffeine as well as other ingredients like taurine, guarana, and B vitamins. The term energy drink was coined by the beverage industry, and despite the common place term the United States Food and Drug Administration (FDA) and the United States Department of Agriculture (USDA) do not recognize it.   

Literature is limited on the effects of energy drinks and it is not yet known if the reported effects such as improved mental and physical performance, driving ability when tired, and decreased mental fatigue during long periods of concentration. It is not yet known if these are due to the caffeine in the energy drinks or the combination of caffeine and other additives in energy drinks.

A recent study determined that if the average adult consumes less than or equal to 400mg of caffeine a day no adverse effects are shown. However it is easy to go over that amount considering that in an 8 fluid oz serving of coffee ranges from 134-240mg, tea ranges from 48-175mg, and soda ranges from 22-46mg. Most people drink more than one 8 fluid oz. serving of either one of these and then add an energy drink in later in the day and another 72 -150mg of caffeine is also added. However that number is also for one serving. Many energy drink cans contain 2-3 servings, which raises the mg of caffeine to about 294mg per can. Start your morning off with a can of monster or full throttle and later in the day you have some soda with your lunch and perhaps even dinner and you’re already well over the 400mg of caffeine without even adding any coffee or tea to your day. At risk groups, which are women of reproductive age and children are recommended to limit their consumption to less than 300mg and children to less than 2.5mg of caffeine per kg of body weight. Adolescents have been recommended to consume less than 100mg per day due to associated elevated blood pressure. Another thing to keep in mind when paying attention to caffeine content are the extra additives in the energy drinks. These additives are there to enhance the effects of caffeine and some like guarana contain caffeine (1g guarana = 40mg caffeine). The adverse effects of consuming more than 400mg of caffeine in a day, “include nervousness, irritability, sleeplessness, increased urination, abnormal heart rythms (arrhythmia), decreased bone levels, and stomach upset” (Heneman 1). 

Caffeine is considered an ergogenic aid and is known to increase endurance and has been banned by the International Olympic Committee. Research has shown that consumption of caffeine before heavy exercise is safe, however the effects of consuming caffeine along with the other additives in energy drinks before heavy exercise is not yet known and is not recommended at any age. 

Resources
Bakker, Anthony J. & Berg, Helen M.  (2002). "Effect of Taurine on Sarcoplasmic Reticulum Function and
     force in Skinned Fast-twitch Skeletal Muscle Fibres of the Rat."  Journal of Physiology. 10: 1113.