Performance enhancement with supplements: Incongruence between rationale and practice

School of Life Sciences, Faculty of Science, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey, KT1 2EE, UK. .
Journal of the International Society of Sports Nutrition (Impact Factor: 1.91). 11/2007; 4(1):19. DOI: 10.1186/1550-2783-4-19
Source: PubMed

ABSTRACT Athletes are expected to consider multiple factors when making informed decision about nutritional supplement use. Besides rules, regulations and potential health hazards, the efficacy of different nutritional supplements in performance enhancement is a key issue. The aim of this paper was to find evidence for informed decision making by investigating the relationship between specific performance-related reasons for supplement use and the reported use of nutritional supplements.
The 'UK Sport 2005 Drug Free Survey' data (n = 874) were re-analysed using association [chi2] and 'strength of association' tests [varphi] to show the proportion of informed choices and to unveil incongruencies between self-reported supplement use and the underlying motives.
Participants (n = 520) reported supplement use in the pattern of: vitamin C (70.4%), creatine (36.1%), whey protein (30.6%), iron (29.8%), caffeine (23.8%), and ginseng (8.3%) for the following reasons: strength maintenance (38.1%), doctors' advice (24.2%), enhancing endurance (20.0%), ability to train longer (13.3%), and provided by the governing body (3.8%). Of thirty possible associations between the above supplements and reasons, 11 were predictable from literature precedents and only 8 were evidenced and these were not strong (varphi < .7). The best associations were for the ability to train longer with creatine (reported by 73.9%, chi2 = 49.14, p < .001; varphi = .307, p < .001), and maintaining strength with creatine (reported by 62.6%, chi2 = 97.08, p < .001; varphi = .432, p < .001) and whey protein (reported by 56.1%, chi2 = 97.82, p < .001; varphi = .434, p < .001).
This study provided a platform for assessing congruence between athletes' reasons for supplement use and their actual use. These results suggest that a lack of understanding exists in supplement use. There is an urgent need to provide accurate information which will help athletes make informed choices about the use of supplements.

Download full-text


Available from: Declan Naughton, Jan 08, 2014
25 Reads
  • Source
    • "The overall percentage of NS users in sports ranges from 60% to 93% (Braun et al., 2009; Dascombe et al., 2010; Heikkinen et al., 2011; Huang et al., 2006; Petroczi and Naughton, 2008; Ronsen et al., 1999; Striegel et al., 2006). Yet NS are only effective if they are properly consumed and it is known that the excessive use of NS and polypharmacy has been connected to serious health problems (Borrione et al., 2008; Petroczi et al., 2007). Consequently, authors have already noted the need to assess athletes' knowledge of these issues (Zenic et al., 2010; Kondric et al 2011). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Nutrition and doping issues are rarely studied in the sport of tennis. The aims of this investigation were to determine knowledge on doping (KD) and knowledge on sport nutrition (KSN), and corresponding socio-demographic-, sport-, and sport-nutrition- and doping-factors among an international sample of high-level tennis players of both sexes (43 females; 22 years old on average). In the first phase of the investigation, the KSN and KD questionnaires were studied for their reliability and validity. The consumption of NS is found to be very high, with almost of all the females and 80% of the males using NS at least occasionally. The athletes showed a low tendency regarding future doping usage, although most of them are convinced that doping does exist in tennis. Since athletes declared that their coaches are their main source of information about NS and doping, future studies should investigate what coaches actually know about such problems. KSN has been found to be protective against potential doping behavior in the future. Males are found to be more prone to doping than females. Therefore, in order to prevent doping behavior in tennis we strongly suggest intensive educational programs on sports nutrition and doping-related problems. Key PointsThe incidence of nutritional supplementation use among the tennis players is found to be very high, especially among the females.Although most of the subjects are of the opinion that the doping behavior is present in tennis circuit, we have found a low tendency regarding future doping usage, and high levels of athletes' trust in their coaches with regard to nutritional supplementation and doping.There are indices that the knowledge about nutrition is protective factor against potential doping behavior. It clearly reinforces the need to include a wide educational program on sports nutrition in tennis, but also in other sports.
    Journal of sports science & medicine 10/2013; 12(2):290-7. · 1.03 Impact Factor
  • Source
    • "Vitamin C is a reducing agent with antioxidant properties important for human health. Although vitamin C is the most commonly consumed supplement by competitive athletes [4]; there is little evidence to support its use as an ergogenic aid [5]. In fact, vitamin C supplementation may actually block training efficiency in athletes by mediating oxidative stress, thereby preventing some necessary cellular adaptations to exercise [6]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective: Moderate energy restriction and exercise are recommended for effective weight loss. Obese individuals oxidize less fat and report a higher perceived exertion during exercise, characteristics that may negatively influence exercise behavior. Because vitamin C status has been linked to fatigability, we compared the effects of vitamin C supplementation on self-reported fatigue and on the respiratory exchange ratio and the Ratings of Perceived Exertion scale during moderate exercise in healthy obese adults adhering to a hypocaloric diet. Methods: Twenty adults (4 men and 16 women) were stratified and randomly assigned to receive 500 mg of vitamin C (VC) or placebo (CON) daily for 4 wk while adhering to a vitamin C-controlled, calorie-restricted diet. Feelings of general fatigue as assessed by the Profile of Mood States questionnaire were recorded on a separate day from the exercise session at weeks 0 and 4. Participants walked on a treadmill at an intensity of 50% predicted maximal oxygen consumption for 60 min at weeks 0 and 4, and heart rate, respiratory exchange ratio, and Ratings of Perceived Exertion were recorded. Results: After 4 wk, the two groups lost similar amounts of weight (≈ 4 kg), and the respiratory exchange ratio was not altered by group. Heart rate and the Ratings of Perceived Exertion during exercise were significantly decreased in the VC versus the CON group (-11 versus -3 beats/min, P = 0.022, and -1.3 versus +0.1 U, P = 0.001, respectively), and the general fatigue score was decreased 5.9 U for the VC group versus a 1.9 U increase for the CON group (P = 0.001). Conclusion: These data provide preliminary evidence that vitamin C status may influence fatigue, heart rate, and perceptions of exertion during moderate exercise in obese individuals.
    Nutrition 06/2012; 29(1). DOI:10.1016/j.nut.2012.01.021 · 2.93 Impact Factor
  • Source
    • "Similarly, a study made with adolescent athletes in central Nebraska reported only 27% of the athletes having used supplements in the past [21]. These rates of supplementation are considerably lower than percentages of supplementation made with older athletes [4,6,8,10,11,15]. In our study, it was also found that in 2002 athletes in age group of 21-24 years were most frequent DS users, whereas in 2009 athletes in the oldest age group (over 24 years) were more likely to use supplements. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to assess the frequency of use of dietary supplements (DS) among large sample of elite Finnish athletes and to describe possible changes in dietary supplement use between the years 2002 and 2009. A prospective follow-up study was conducted on Olympic athletes. The first survey was conducted on Olympic athletes in 2002 (N = 446) and the follow-up study was conducted between May 2008 and June 2009 (N = 372). In 2002, a total of 81% of the athletes used dietary supplements (a mean of 3.37 ± 3.06 DS per user) and in 2009, a total of 73% of the athletes (a mean of 2.60 ± 2.69 per DS user) used them. After adjusting for age-, sex- and sport type, the OR (95% confidence interval, CI) for use of any dietary supplement was significantly less in 2009 as compared with 2002 results (OR, 0.62; 95% CI, 0.43-0.90). Decrease in DS use was observed in all supplement subgroups (vitamins, minerals, nutritional supplements). Athletes in speed and power events and endurance events reported use of any dietary supplement significantly more often than team sport athletes both in 2002 and 2009. In year 2009, the frequency of all dietary supplement use increased when athlete's age increased and the increase was significant in older age groups: of the athletes under 21 years 63%, 21-24 years 83% and over 24 years 90% consumed nutritional supplements. Based in our study, there seems to be a lowering trend of dietary supplement use among elite Finnish athletes although differences between sport subgroups and age groups are considerable.
    Journal of the International Society of Sports Nutrition 02/2011; 8(1):1. DOI:10.1186/1550-2783-8-1 · 1.91 Impact Factor
Show more