scholarly journals The effects of Guarana (Paullinia cupana) supplementation on the cognitive performance of young healthy adults – a Systematic Review

2019 ◽  
Vol 2 (2) ◽  
pp. 171-182
Author(s):  
Fanaras Konstantinos ◽  
Reinhard Heun

AbstractObjectivesGuarana (Paullinia cupana) from the Sapindaceae family, native to the Amazon basin, is a natural stimulant herb that can be found in popular energy drinks, pharmaceutical shops or local herb shops. With the use of natural health products increasing, guarana has gained a fair amount of popularity in the past years. In this systematic review, we examined the effects of guarana supplementation on cognitive performance. A secondary objective was to compare guarana with caffeine on cognitive performance.MethodsSearches were made in PubMed using the terms ‘Guarana’ or ‘Paullinia cupana’. Filters focused on Controlled Clinical trials. Inclusion criteria were met by studies using interventions with guarana, while focusing on guarana’s effects on cognition. Participants needed to be young, healthy adults. Studies not published in English or Greek were excluded. The last date of our search was March 7, 2019.ResultsA total of 29 studies were identified and screened. After screening, 17 studies were excluded. The remaining 12 studies were found eligible for data extraction. After reading the full text of the 12 studies, 3 studies were excluded. In the end, 9 studies were found eligible for our systematic review (n = 369 participants). In these studies, guarana showed to improve reaction time and accuracy of performance at cognitive tasks. No significant differences were found when comparing guarana with caffeine.ConclusionGuarana seems to improve reaction time and accuracy of performance at tasks, but no significant effects were found when compared with caffeine. High quality randomized controlled clinical trials with a low risk of bias are needed to further study the herb.

2021 ◽  
Vol 15 ◽  
pp. 175346662110280
Author(s):  
Roberto Ariel Abeldaño Zuñiga ◽  
Ruth Ana María González-Villoria ◽  
María Vanesa Elizondo ◽  
Anel Yaneli Nicolás Osorio ◽  
David Gómez Martínez ◽  
...  

Aims: Given the variability of previously reported results, this systematic review aims to determine the clinical effectiveness of convalescent plasma employed in the treatment of hospitalized patients diagnosed with COVID-19. Methods: We conducted a systematic review of controlled clinical trials assessing treatment with convalescent plasma for hospitalized patients diagnosed with SARS-CoV-2 infection. The outcomes were mortality, clinical improvement, and ventilation requirement. Results: A total of 51 studies were retrieved from the databases. Five articles were finally included in the data extraction and qualitative and quantitative synthesis of results. The overall risk of bias in the reviewed articles was established at low-risk only in two trials. The meta-analysis suggests that there is no benefit of convalescent plasma compared with standard care or placebo in reducing the overall mortality and the ventilation requirement. However, there could be a benefit for the clinical improvement in patients treated with plasma. Conclusion: Current results led to assume that the convalescent plasma transfusion cannot reduce the mortality or ventilation requirement in hospitalized patients diagnosed with SARS-CoV-2 infection. More controlled clinical trials conducted with methodologies that ensure a low risk of bias are still needed. The reviews of this paper are available via the supplemental material section.


2021 ◽  
Author(s):  
Roberto Ariel Abeldaño Zuñiga ◽  
Ruth Ana María González Villoria ◽  
María Vanesa Elizondo ◽  
Anel Yaneli Nicolás Osorio ◽  
Silvia Mercedes Coca

AbstractGiven the variability of previously reported results, this systematic review aims to determine the clinical effectiveness of convalescent plasma employed in the treatment of hospitalized patients with diagnosis of COVID-19.We conducted a systematic review of controlled clinical trials assessing treatment with convalescent plasma for hospitalized patients with a diagnosis of SARS-CoV-2 infection. The outcomes were mortality, clinical improvement, and ventilation requirement.A total of 50 studies were retrieved from the databases. Four articles were finally included in the data extraction, qualitative and quantitative synthesis of results. The meta-analysis suggests that there is no benefit of convalescent plasma compared to standard care or placebo in the reduction of the overall mortality and in the ventilation requirement; but there could be a benefit for the clinical improvement in patients treated with plasma.We can conclude that the convalescent plasma transfusion cannot reduce the mortality or ventilation requirement in hospitalized patients diagnosed with SARS-CoV-2 infection. More controlled clinical trials conducted with methodologies that ensure a low risk of bias are still needed.


Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 868
Author(s):  
Jorge Lorenzo Calvo ◽  
Xueyin Fei ◽  
Raúl Domínguez ◽  
Helios Pareja-Galeano

Cognitive functions are essential in any form of exercise. Recently, interest has mounted in addressing the relationship between caffeine intake and cognitive performance during sports practice. This review examines this relationship through a structured search of the databases Medline/PubMed and Web of Science for relevant articles published in English from August 1999 to March 2020. The study followed PRISMA guidelines. Inclusion criteria were defined according to the PICOS model. The identified records reported on randomized cross-over studies in which caffeine intake (as drinks, capsules, energy bars, or gum) was compared to an identical placebo situation. There were no filters on participants’ training level, gender, or age. For the systematic review, 13 studies examining the impacts of caffeine on objective measures of cognitive performance or self-reported cognitive performance were selected. Five of these studies were also subjected to meta-analysis. After pooling data in the meta-analysis, the significant impacts of caffeine only emerged on attention, accuracy, and speed. The results of the 13 studies, nevertheless, suggest that the intake of a low/moderate dose of caffeine before and/or during exercise can improve self-reported energy, mood, and cognitive functions, such as attention; it may also improve simple reaction time, choice reaction time, memory, or fatigue, however, this may depend on the research protocols.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Melina von Wernsdorff ◽  
Martin Loef ◽  
Brunna Tuschen-Caffier ◽  
Stefan Schmidt

AbstractOpen-label placebos (OLPs) are placebos without deception in the sense that patients know that they are receiving a placebo. The objective of our study is to systematically review and analyze the effect of OLPs in comparison to no treatment in clinical trials. A systematic literature search was carried out in February 2020. Randomized controlled trials of any medical condition or mental disorder comparing OLPs to no treatment were included. Data extraction and risk of bias rating were independently assessed. 1246 records were screened and thirteen studies were included into the systematic review. Eleven trials were eligible for meta-analysis. These trials assessed effects of OLPs on back pain, cancer-related fatigue, attention deficit hyperactivity disorder, allergic rhinitis, major depression, irritable bowel syndrome and menopausal hot flushes. Risk of bias was moderate among all studies. We found a significant overall effect (standardized mean difference = 0.72, 95% Cl 0.39–1.05, p < 0.0001, I2 = 76%) of OLP. Thus, OLPs appear to be a promising treatment in different conditions but the respective research is in its infancy. More research is needed, especially with respect to different medical and mental disorders and instructions accompanying the OLP administration as well as the role of expectations and mindsets.


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