Introduction: The use of dietary supplements is increasing among athletes, year after year. Related to the high rates of use, unintentional doping occurs. Unintentional doping refers to positive anti-doping tests due to the use of any supplement containing unlisted substances banned by anti-doping regulations and organizations, such as the World Anti-Doping Agency (WADA). The objective of this review is to summarize the presence of unlabeled doping substances in dietary supplements that are used in sports. Methodology: A review of substances/metabolites/markers banned by WADA in ergonutritional supplements was completed using PubMed. The inclusion criteria were studies published up until September 2017, which analyzed the content of substances, metabolites and markers banned by WADA. Results: 446 studies were identified, 23 of which fulfilled all the inclusion criteria. In most of the studies, the purpose was to identify doping substances in dietary supplements. Discussion: Substances prohibited by WADA were found in most of the supplements analyzed in this review. Some of them were prohormones and/or stimulants. With rates of contamination between 12 and 58%, non-intentional doping is a point to take into account before establishing a supplementation program. Athletes and coaches must be aware of the problems related to the use of any contaminated supplement and should pay special attention before choosing a supplement, informing themselves fully and confirming the guarantees offered by the supplement.
The consumption of nutritional ergogenic aids is conditioned by laws/regulations, but standards/regulations vary between countries. The aim of this review is to explore legislative documents that regulate the use of nutritional ergogenic aids intended for sportspeople in a Spanish/European framework. A narrative review has been developed from official websites of Spanish (Spanish Agency of the Consumer, Food Safety, and Nutrition) and European (European Commission and European Food Safety Authority) bodies. A descriptive analysis of documents was performed. Eighteen legislative documents have been compiled in three sections: (1) Advertising of any type of food and/or product; (2) Composition, labeling, and advertising of foods; (3) Nutritional ergogenic aids. In spite of the existence of these legal documents, the regulation lacks guidance on the use/application of nutritional ergogenic aids for sportspeople. It is essential to prevent the introduction or dissemination of false, ambiguous, or inexact information and contents that induce an error in the receivers of the information. In this field, it is worth highlighting the roles of the European Food Safety Authority and the World Anti-Doping Agency, which provide information about consumer guidelines, prescribing practices, and recommendations for the prudent use of nutritional ergogenic aids.
REFERENCELos autores originales no han revisado ni verificado la traducción del manuscrito al español, y no necesariamente están de acuerdo con su contenido.
Objective
This living systematic review aims to provide a timely, rigorous and continuously updated summary of the evidence available on the role of vitamin C in the treatment of patients with COVID-19.
Data sources
We will conduct searches in PubMed/Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), grey literature and in a centralised repository in L OVE (Living OVerview of Evidence). L OVE is a platform that maps PICO questions to evidence from Epistemonikos database. In response to the COVID-19 emergency, L OVE was adapted to expand the range of evidence it covers and customised to group all COVID-19 evidence in one place. The search will cover the period until the day before submission to a journal.
Eligibility criteria for selecting studies and methods
We adapted an already published common protocol for multiple parallel systematic reviews to the specificities of this question.
We will include randomised trials evaluating the effect of vitamin C, as monotherapy or in combination with other drugs, versus placebo or no treatment in patients with COVID-19. Randomised trials evaluating vitamin C in infections caused by other coronaviruses, such as MERS-CoV and SARS-CoV, and non-randomised studies in COVID-19 will be searched in case no direct evidence from randomised trials is found, or if the direct evidence provides low- or very low-certainty for critical outcomes.
Two reviewers will independently screen each study for eligibility, extract data, and assess the risk of bias. We will pool the results using meta-analysis and will apply the GRADE system to assess the certainty of the evidence for each outcome.
A living, web-based version of this review will be openly available during the COVID-19 pandemic. We will resubmit it every time the conclusions change or whenever there are substantial updates.
Ethics and dissemination
No ethics approval is considered necessary. The results of this review will be widely disseminated via peer-reviewed publications, social networks and traditional media.
PROSPERO Registration
Submitted to PROSPERO (awaiting ID allocation).
Keywords
COVID-19, severe acute respiratory syndrome coronavirus 2, Coronavirus Infections, Systematic review, vitamin c, ascorbic acid.
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