Rich in caffeine, guarana (Paullinia cupana) is renowned for its stimulating effects on energy, concentration and metabolism. Used in herbal medicine, it helps to reduce fatigue, improve cognitive performance and support weight loss. Find out more about its benefits, its uses and the precautions to take for optimum consumption.
What are the main pharmacological properties of Guarana seeds?
Guarana seeds are rich in methylxanthines, including mainly caffeine (around 3 to 5%), sometimes called guaranine, as well as other alkaloids such as theophylline and theobromine. They also contain catechins and polyphenols. Known as a stimulant psychotropic, guarana is traditionally used in indigenous South American medicine as a tonic, anti-diarrhoeal and anti-neuralgic. It is also recommended for slimming diets. Historically, various pre-Columbian tribes, such as the Andira and Satéré-mawé, used it in phytotherapy to treat a wide range of ailments. The Amerindians transform the roasted and shelled seeds into a paste, then dry and grate it to prepare çapo, a traditional drink. Renowned for its aphrodisiac properties, this drink acts on the encephalic nerve centres to stimulate erogenous activity.
A physical and mental stimulant
The plant’s traditional use to boost physical capacity and reduce fatigue is linked to the properties of guaranine, also known as caffeine. This alkaloid, a member of the methylxanthine family, has a positive inotropic and negative chronotropic effect and stimulates respiration in the bulbar centres. It increases blood pressure and muscle blood flow (but does not alter cerebral vascular flow), and improves oxygen supply to the muscles. It mobilises intracellular calcium, and reduces coagulation time, platelet aggregation and thromboxane synthesis.
By antagonising adenosine, caffeine reduces the feeling of tiredness.
Guarana also stimulates cognitive capacity in vivo, particularly memory capacity. It promotes the release of acetylcholine in the hippocampus and cortex. The positive psychostimulant effects of guarana have been proven in humans. These include improved memory, perception,learning,attention, alertness, intellectual capacity and coordination. In 2007, a double-blind, placebo-controlled study was conducted on 26 patients. They were given different doses of guarana for 6 days. The results showed an improvement in cognitive capacity and mood. These improvements were measured using two tools.
The authors of this study noted a dose-dependent improvement in memory, mental alertness and feelings of satisfaction. In addition to the known psychostimulant effect of caffeine, they suggest that other components contained in guarana could also explain the positive effects described.
Neuroprotective properties
In vivo and in vitro, after exposure to methyl mercury, guarana has protective effects on survival,locomotor activity, sleep and behaviour, while reducing inflammatory changes.
Guarana also protects the SH-SY5Y human dopaminergic neuroblastoma cell line against rotenone-induced cytotoxicity in vitro. This neuroprotective effect on dopaminergic neurons paves the way for its possible use in Parkinson’s disease.
In addition, a 2018 study demonstrated that chronic administration of ethanolic extract of P. cupana decreases the formation of insoluble amyloid β (Aβ) protein aggregates in a Caenorhabditis elegans model of Alzheimer’s disease via activation of the heat shock protein (HSP) response, thereby preventing behavioural deficits and oxidative damage associated with Aβ toxicity.
A study from the same year used a hydroalcoholic extract of guarana on C. elegans models. This study targeted Alzheimer’s and Huntington’s diseases. The results showed an increase in antioxidant activity and a modulation of proteostasis. This led to a longer lifespan and increased proteasome activity. The study also observed a reduction in intracellular reactive oxygen species (ROS). In addition, there was a reduction in the accumulation of autophagosomes. Expression of superoxide oxidase 3 (SOD-3) and heat shock protein 16.2 (HSP-16.2) increased. These results suggest that guarana could be therapeutic against amyloidogenic diseases. It could also be useful against other age-related neurodegenerative diseases.
Regulation of satiety
A clinical study shows that guarana slows down digestion. This increases the duration of satiety. However, its effect on weight loss is unclear. Studies suggest that the caffeine in guarana may speed up metabolism. But these effects are limited. A large quantity of guarana would be needed for significant weight loss.
Weight loss depends on a number of factors. These include diet, exercise, genetics and lifestyle. To lose weight healthily, a balanced diet and regular exercise are essential.
It’s important to remember that there is no miracle solution to weight loss. A balanced diet is essential for a healthy weight. Regular physical activity is also crucial. Healthy lifestyle habits play an important role. This includes getting adequate sleep and avoiding alcohol and tobacco. These factors are key to achieving and maintaining an ideal weight. It is advisable to consult a health professional. He or she can create a personalised eating plan.
Metabolic properties
Guarana is traditionally used as an adjunct to slimming diets. An epidemiological study conducted in 2011 in the Amazon among people aged over 60 showed a better metabolic status among regular guarana users: lower waist circumference, less obesity and arterial hypertension, lower LDL cholesterol levels (in women).
Clinical studies on obese subjects have shown that caffeine or guarana combined with other plants have a significant effect on weight loss and weight stabilisation after dieting, on reducing body fat, on energy expenditure in healthy subjects, on improving basal metabolic rate (10%), and on increasing thermogenic activity (as demonstrated after ingestion of a single dose of guarana) (measurable by an increase in the respiratory quotient, which reflects lipid oxidation). These metabolic effects are nevertheless attributed to caffeine, which has been shown to have an effect on energy balance and increase daily energy expenditure.
