Many studies have found that some dietary supplement product labels do not accurately reflect the actual ingredients. However, studies have not been performed to determine if ingredients in the same dietary supplement product vary over time. The objective of this study was to assess the consistency of stimulant ingredients in popular sports supplements sold in the United States over a 9-month period. Three samples of nine popular sports supplements were purchased over the 9-month period. The 27 samples were analyzed for caffeine and several other stimulants (including adulterants). The identity and quantity of stimulants were compared with stimulants listed on the label and stimulants found at earlier time points to determine the variability in individual products over the 9-month period. The primary outcome measure was the variability of stimulant amounts in the products examined. Many supplements did not contain the same number and quantity of stimulants at all time points over the 9-month period. Caffeine content varied widely in five of the six caffeinated supplements compared with the initial measurement (–7% to +266%). In addition, the stimulants—synephrine, octopamine, cathine, ephedrine, pseudoephedrine, strychnine, and methylephedrine—occurred in variable amounts in eight of the nine products. The significance of these findings is uncertain: the sample size was insufficient to support statistical analysis. In our sample of nine popular sports supplements, the presence and quantity of stimulants varied over a 9-month period. However, future studies are warranted to determine if the variability found is significant and generalizable to other supplements.
Selasi Attipoe, Pieter A. Cohen, Amy Eichner and Patricia A. Deuster
Suelen Galante Inácio, Gustavo Vieira de Oliveira and Thiago Silveira Alvares
Caffeine and creatine are ingredients in the most popular dietary supplements consumed by soccer players. However, some products may not contain the disclosed amounts of the ingredients listed on the label, compromising the safe usage and the effectiveness of these supplements. Therefore, the aim of this study was to evaluate the content of caffeine and creatine in dietary supplements consumed by Brazilian soccer players. The results obtained were compared with the caffeine content listed on the product label. Two batches of the supplement brands consumed by ≥ 50% of the players were considered for analysis. The quantification of caffeine and creatine in the supplements was determined by a high-performance liquid chromatography system with UV detector. Nine supplements of caffeine and 7 supplements of creatine met the inclusion criteria for analysis. Eight brands of caffeine and five brands of creatine showed significantly different values (p < .05) as compared with the values stated on the label. There were no significant differences between the two batches of supplements analyzed, except for one caffeine supplement. It can be concluded that caffeine and creatine dietary supplements consumed by Brazilian soccer players present inaccurate values listed on the label, although most presented no difference among batches. To ensure consumer safety and product efficacy, accurate information on caffeine and creatine content should be provided on all dietary supplement labels.
Michal Kumstát, Silvie Rybářová, Andy Thomas and Jan Novotný
The nutritional intake of elite open water swimmers during competition is not well established, and therefore this case study aims to provide new insights by describing the feeding strategies adopted by an elite female swimmer (28 yrs; height; 1.71 m; body mass: 60 kg; body fat: 16.0%) in the FINA open water Grand Prix 2014.Seven events of varying distances (15–88 km) and durations (3–12 hrs) were included. In all events, except one, feeds were provided from support boats. Swimmer and support staff were instructed to track in detail all foods and beverages consumed during the events. Nutritional information was gathered from the packaging and dietary supplements labels and analyzed by nutrition software. Mean carbohydrate (CHO) and protein intake reached 83 ± 5 g·h-1 and 12 ± 8 g·h-1, respectively. Fat intake was neglected (~1 g·h-1). Mean in-race energy intake reached 394 ± 26 kcal·h-1. Dietary supplements in the form of sport beverages and gels, containing multitransportable CHO, provided 40 ± 4 and 49 ± 6% of all CHO energy, respectively. Caffeine (3.6 ± 1.8 mg·kg-1 per event) and sodium (423 ± 16 mg·h-1) were additionally supplemented in all events. It was established that continuous intake of high doses of CHO and sodium and moderate dose of caffeine were an essential part of the feeding strategy for elite-level high intensity ultra-endurance open-water swimming races. A well scheduled and well-prepared nutrition strategy is believed to have ensured optimal individual performance during Grand Prix events.