The Amazon is a dangerous place, with jaguars, anacondas and piranhas in constant search for their next meal, but you would not have anything to fear from guarana. It isn’t a predator, it’s a woody vine that climbs through the trees, growing up to 30 feet long. It produces bright red berries that split open when ripe, revealing a shiny black seed partially embedded in a thin white pulp. From a distance, the split berries look disturbingly like eyes staring down from the leafy canopy. The name “guarana” reflects this connection, deriving from the native words “guara” for “human,” and “na” for “like.”Â
Amazonian natives had discovered the invigorating effects of guarana long before Europeans ever arrived in South America. Traditionally they ground the dried seeds into a paste that was then formed into sticks. Grating the dried sticks into water produced a beverage that was mainly used as a stimulant. And did it ever stimulate! No great surprise there for the simple reason that guarana is a rich source of caffeine and also contains theobromine and theophylline, stimulants very similar to caffeine. Sometimes the three stimulants are collectively referred to as guaranine.Â
On a weight-per-weight basis, guarana seeds contain about twice as much caffeine as a coffee bean! Indeed, in South America, most of the caffeine used in beverages and pills is extracted not from coffee beans, but from guarana seeds. Extracts of the berries are also used to flavour soft drinks which are extremely popular in Brazil. Besides looking for a stimulant effect, Brazilians also consume guarana in the form of candies, syrups and various herbal tonics with hopes of “purifying the blood,” preventing premature ageing and reducing the appetite. While caffeine does have an appetite suppressing effect, the other claims are pure whimsy.  Â
Guarana has now wended its way to North America where it is most likely to be found as a component of “energy drinks” that claim to provide consumers with, what else, extra energy. That energy comes from a good jolt of caffeine, a hefty dose of which comes from guarana, but carnitine, glucuronolactone, inositol, ginseng, hydroxy citric acid, taurine and yohimbine are also commonly added in various combinations with claims ranging from improving endurance and suppressing appetite to boosting sexual performance and promoting the excretion of toxins.  Â
The stimulant effect of caffeine is of course very real, but the other claims lack scientific evidence. While modest amounts of caffeine do not pose a problem, and may indeed help with mental alertness and exercise endurance, some of the energy drinks contain as much as 300 mg of caffeine per bottle. That’s more than double the amount found in the strongest cup of coffee. Such a dose can not only make one jittery, it can affect blood pressure, cause palpitations, and in rare cases, even seizures. Doctors at St. Joseph’s Hospital and Medical Center in Phoenix report a series of four young patients who had seizures on multiple occasions following heavy consumption of energy drinks. Once they were told to abstain from the beverages, the seizures ceased.  Because the drinks contain multiple components it is not possible to say with certainty that caffeine is the culprit, but it is the most likely candidate. The seizures were most common when the drinks were consumed on an empty stomach.  Â
There is also concern about consuming guarana in any form together with alcohol. Guarana, because of its high caffeine content, produces a sensation of alertness which may cause imbibers to overlook the debilitating effects of intoxication. A recent study reports that consuming alcohol with energy drinks leads to a reduced feeling of intoxication while having no effect on objective measures of motor coordination and reaction time. This means that someone who has consumed alcohol and guarana may feel that they can drive because they don’t feel drunk.  But they may well be. Guarana berries may look like they're looking at you, but they are not looking out for you.
