Guarana: A Stimulating Beverage
Although primarily used in South America, guarana—called "Zoom" by some due to its familiar stimulating effects—has infiltrated the American health food market in the last few years. This herb derives its name from the Guaranis, South American Indians, who used the preparation in various foods, much in the same way we use chocolate. Seeds from guarana are shelled and dry-roasted, coarsely powdered, mixed with water and/or cassava, and kneaded into a paste. The paste is then shaped into cylindrical masses and dried. These resultant "sticks", which have little smell and an astringent, bitter taste (like chocolate without its oiliness), are then grated into water. Today, Brazil’s soft drink industries use the same preparation, with the addition of carbonation. Guarana is also sometimes mixed with alcohol to make a more intoxicating beverage.
Historically, the stems, leaves, and roots of guarana are used as a fish-killing drug in Central and South America. In Africa it is used in the treatment of dysentery and as a sexual stimulant. The Guaranis also used guarana as a preventative and curative for "bowel complaints". Because of its astringent properties, guarana was once used therapeutically for recovery from diarrhea and leukorrhea, but other herbs have since supplanted guarana for these purposes.
Eclectic doctors in the early 1900s describe guarana’s indications as weak pulse, pale complexion, and migraine and menstrual-related headaches, while current use of guarana is primarily for nervous headaches, mental fatigue, and heat exhaustion. Smaller doses are reported to be more efficacious than larger ones, a medium dose being 10 drops of tincture or 1 "oo" capsule. Contraindications include neuralgia, chronic headaches, heart palpitations, and high temperatures.
In a recent scientific study, a water extract of guarana was shown to inhibit platelet aggregation in rabbits following either intravenous or oral administration.
Guarana has practically the same chemical composition as coffee and has the same physiological actions, thus its use for mental fatigue and heat exhaustion. In fact, some authors argue that its main component, guaranine is simply caffeine. It contains up to 7% of guaranine or caffeine (as compared to about 2% in coffee), with theobromine, theophylline, xanthine, and other xanthine derivatives, as well as an appreciable amount of tannins (approximately 12%, including d-catechin), and saponins, starch, fats, choline, and pigments.
Guarana’s appetite-suppressing qualities are due to its caffeine content, which is also responsible for the rush of energy felt by people taking guarana tablets (thus, the name "Zoom"). Guarana is included as an ingredient in some weight-reducing products but should be used cautiously by people suffering from cardiovascular disease. There are no published toxic effects from taking guarana, but those sensitive to caffeine could expect similar side effects from it, such as gastrointestinal and central nervous system irritation.
Guarana is considered to be an ideal crop to supplement the incomes of small peasant farmers in the Amazon basin. As a rapidly-growing perennial, guarana can be planted in the midst of manioc crops. Hand-processing of guarana causes a higher quality finished product. The Indians’ concern is to avoid oxidation of the phenolic compounds in the seed, since this can cause guarana to turn dark, become bitter in taste, and irritate the gastrointestinal tract. The short-term medicinal effects of guarana are thought to result from the high caffeine content, as well as from tannins. Future research may prove saponins to also be important, especially in guarana’s long-term activity as a general tonic and prophylactic.
To summarize, guarana (Paullinia cupana) is a large climbing woody-shrub native to Brazil, and it has been used for headache, for excess mental work, for fatigue from hot weather, and more recently for weight loss.