Effect of Guarana (Paullinia cupana) on Cognitive Performance: A Systematic Review and Meta-Analysis

Abstract

The plant extract guarana is known for its caffeine content and other bioactive ingredients, which purportedly may improve cognitive performance. Recent reviews have examined the effects of chronic supplementation of guarana in clinical populations; however, the acute effects of guarana on cognitive tasks, while of interest, have produced mixed results. Whether acute guarana ingestion improves human cognitive performance was assessed by performing a systematic review coupled with a meta-analysis. Eight placebo-controlled studies were identified and met the inclusion criteria providing data on 328 participants. The dose of guarana (37.5 to 500 mg) with reported caffeine content (4.3 to 100 mg) varied. Effect sizes (ESs) were calculated as the standardized mean difference and meta-analyses were completed using a random-effects model. The ESs for guarana averaged across a variety of cognitive measures and outcome variables were less than trivial (Hedge’s g = 0.076, p = 0.14). Using a subgroup meta-analysis (Q = 12.9, p < 0.001), ESs indicating a faster response time for guarana vs. a placebo (g = 0.202, p = 0.005) differed from the accuracy measures (g = −0.077, p = 0.4) which were non-significant. For response time, guarana ingested in a capsule (g = 0.111) tended to differ (Q = 2.96, p = 0.085) compared to guarana when dissolved in liquid (g = 0.281). Meta-regression of the study ESs of overall cognitive task performance was not related to the guarana dose (R2 < 0.001) or to the time allowed prior to cognitive testing (R2 < 0.001). Acute guarana ingestion had a small effect on the response time (faster performance) during a variety of cognitive tasks without affecting the accuracy. Whether the changes were linked to the caffeine content or other bioavailable substances in guarana is unknown. Additional studies that directly compare matched doses of caffeine versus guarana are needed to understand its effects on cognitive performance.

Effects of Acute Guarana (Paullinia cupana) Ingestion on Mental Performance and Vagal Modulation Compared to a Low Dose of Caffeine

“…In this present study, the lack of discernible differences between treatments in the Simon and 2N-Back Tasks indicates that GUA had no beneficial effects on the respective response inhibition and working memory parameters assessed under either the normal or physically fatigued states. This conflicts with other individual studies compiled earlier [ 27 ] which found that a single dose of 37.5 mg and 75 mg Guarana increased the secondary memory accuracy of activities in Cognitive Drug Research (CDR) Computerized Assessment Battery among healthy young adults [ 28 ]. In relation to memory improvements, another study [ 29 ] also found that participants who took 75 mg of Guarana displayed improved scores in secondary memory activities of the CDR Computerized Assessment Battery at 150 min after ingestion compared to the placebo.…”

“…This present study failed to align with some research findings that the benefits obtained after consuming Guarana are associated with greater cognitive performance improvements than the caffeine content alone might suggest [ 43 ]. An earlier meta-analysis [ 27 ] from our group indicated that acute Guarana ingestion may influence specific response time outcomes with a small magnitude of effect, but not the accuracy in various cognitive performance assessments. In contrast, the present study found no difference in RT among treatments in cognitive measures involving attention and working memory.…”

“…Faster response times (RT) in a Go/No-go Task were found with Guarana (GUA) compared to caffeine (CAF) [ 25 ]; but in another study, no differences were found between GUA and CAF for RT during a Simon Task [ 26 ]. Furthermore, a meta-analysis of eight placebo-controlled studies indicated that GUA slightly improves RT in cognitive tests without affecting performance accuracy [ 27 ]. Moreover, other individual studies have revealed the potential of GUA to enhance alertness, secondary memory accuracy, and working memory, as measured by different cognitive and mood assessments [ 28 , 29 ].…”

Comment on Hack et al. Effect of Guarana (Paullinia cupana) on Cognitive Performance: A Systematic Review and Meta-Analysis. Nutrients 2023, 15, 434

“…We have read the recent systematic review and meta-analysis by Hack et al [1] entitled "Effect of Guarana (Paullinia cupana) on Cognitive Performance: A Systematic Review and Meta-Analysis" with great interest and we appreciate the authors' contribution to this emerging field. We would like to draw the authors and reader attention to recently published data [2] which may support and strengthen their overall conclusions.…”

Reply to Gurney, T.; Ronca, F. Comment on “Hack et al. Effect of Guarana (Paullinia cupana) on Cognitive Performance: A Systematic Review and Meta-Analysis. Nutrients 2023, 15, 434”

“…We thank Dr. Gurney for his interest and comment [1] on our recent systematic review and meta-analysis quantifying the effect of Guarana on cognitive performance [2]. Our paper compared the acute effect of Guarana ingestion versus a placebo on a variety of cognitive tasks without the additional influence of exercise.…”