appropriate source of carbohydrate. This is an important consideration since there are a wide variety of supplemental and real food carbohydrate sources available to the athlete. Specific supplemental carbohydrate sources produced for athletes include drinks, gels, and chews/sweets, while real food options
Kirsty M. Reynolds, Tom Clifford, Stephen A. Mears, and Lewis J. James
Anna Baylis, David Cameron-Smith, and Louise M. Burke
Many athletes report using a wide range of special sports foods and supplements. In the present study of 77 elite Australian swimmers, 99% of those surveyed reported the use of these special preparations, with 94% of swimmers reporting the use of non-food supplements. The most popular dietary supplements were vitamin or mineral supplements (used by 94% of the group), herbal preparations (61%), and creatine (31%). Eighty-seven percent of swimmers reported using a sports drink or other energy-providing sports food. In total, 207 different products were reported in this survey. Sports supplements, particularly supplements presented as pills or other non-food form, are poorly regulated in most countries, with little assurance of quality control. The risk of an inadvertent “positive doping test” through the use of sports supplements or sports foods is a small but real problem facing athletes who compete in events governed by anti-doping rules. The elite swimmers in this survey reported that information about the “doping safety” of supplements was important and should be funded by supplement manufacturers. Although it is challenging to provide such information, we suggest a model to provide an accredited testing program suitable for the Australian situation, with targeted athlete education about the “sports safety” of sports supplements and foods.
Michael C. Scally and Andrew Hodge
Prior to presentation, two physically fit adults, a 39-year-old male and 40-year-old female, began supplementation with an over-the-counter thyroid preparation marketed as a metabolic accelerator and fat loss aid, tiratricol. Both participants took the supplement for 5 weeks (3000–4000 mcg/d) and 3 weeks (6000 mcg/d), respectively. At presentation, both complained of lethargy, loss of appetite, and muscle weakness. Upon initial laboratory evaluation, results revealed low thyroid stimulating hormone with profoundly elevated T3 values in both patients. After an extensive review of the literature, the cause of the problem was found to be the nutritional supplement they consumed contained tiratricol. After discontinuation of the supplement, thyroid levels slowly returned to baseline 40 days and 5 months later, respectively.
Melissa J. Crowe, Donna M. O’Connor, and Joann E. Lukins
This study aimed to investigate the effects of 6 wk oral supplementation of ß-hydroxy- ß-methylbutyrate (HMB) and HMB combined with creatine monohy-drate (HMBCr) on indices of health in highly trained athletes. Elite, male rugby league players (n = 28) were allocated to 1 of 3 groups: a control group (n = 6), a HMB group (3 g/d; n = 11), or a HMBCr group (3 g/day HMB, 3 g/d Cr; n = 11). Testing prior to, and immediately following, supplementation included a full blood count, plasma testosterone and cortisol, blood electrolytes, lipids, urea and glucose, sperm count and motility, and assessment of psychological state. A 3 X 2 factorial ANOVA revealed no effect of HMB or HMBCr on any of the measured parameters except minor changes in blood bicarbonate and blood monocyte and lymphocyte counts. Blood bicarbonate was significantly decreased in the HMB post-supplementation sample compared to the control and HMBCr groups. Blood monocyte and lymphocyte counts showed no within-group changes for HMB or HMBCr supplementation but were significantly different from the control. However, the majority of these readings remained within normal range. HMB and HMBCr were concluded to have no adverse effects on the parameters evaluated in this study when taken orally by highly trained male athletes over a 6-wk period.
Victor Lun, Kelly A. Erdman, Tak S. Fung, and Raylene A. Reimer
Dietary supplementation is a common practice in athletes with a desire to enhance performance, training, exercise recovery, and health. Supplementation habits of elite athletes in western Canada have been documented, but research is lacking on supplement use by athletes across Canada. The purpose of this descriptive study was to evaluate the dietary supplementation practices and perspectives of high-performance Canadian athletes affiliated with each of the country’s eight Canadian Sport Centres. Dietitians administered a validated survey to 440 athletes (63% women, 37% men; M =19.99 ± 5.20 yr) representing 34 sports who predominantly trained ≥16 hr/wk, most competing in “power” based sports. Within the previous 6 months, 87% declared having taken ≥3 dietary supplements, with sports drinks, multivitamin and mineral preparations, carbohydrate sports bars, protein powder, and meal-replacement products the most prevalent supplements reported. Primary sources of information on supplementation, supplementation justification, and preferred means of supplementation education were identified. Fifty-nine percent reported awareness of current World Anti-Doping Agency legislation, and 83% subjectively believed they were in compliance with such antidoping regulations. It was concluded that supplementation rates are not declining in Canada, current advisors on supplementation for this athletic population are not credible, and sports medicine physicians and dietitians need to consider proactive strategies to improve their influence on supplementation practices in these elite athletes.
Dietary supplements encompass a wide range of products, including essential nutrients (vitamins, minerals, proteins, amino acids, etc.), herbals and botanicals, and specific products with potential for maintenance of health and optimisation of performance. The use of dietary supplements is
Edgar J. Gallardo and Andrew R. Coggan
contain articles extolling the virtues of BRJ supplementation as an ergogenic aid, and a large number of BRJ supplements in various forms (i.e., powders, mixed drinks, concentrates, bulk juice) are now marketed to athletes. However, the NO 3 − content of beets or BRJ depends heavily on a number of
Jozo Grgic, Sandro Venier, and Pavle Mikulic
The acute ergogenic effects of caffeine supplementation on exercise performance are well established. 1 – 3 Traditionally, the effects of caffeine on exercise performance are explored by testing the subjects after they ingest caffeine on one occasion and placebo on another occasion. In such a
Neil D. Clarke and Darren L. Richardson
firing rates, pain suppression, reduced fatigue, and improved neuromuscular performance ( Davis & Green, 2009 ; Graham, 2001 ). However, there has been a long-standing paradigm that habitual caffeine intake may influence the ergogenicity of caffeine supplementation ( Sökmen et al., 2008 ), and thus
Harry Pope, Max Davis, M. Begona Delgado-Charro, Oliver J. Peacock, Javier Gonzalez, and James A. Betts
for dietary phosphate supplementation to improve physical function (i.e., performance). Almost 40 years ago, Cade et al. ( 1984 ) first reported that phosphate loading for 4 days can increase both maximal oxygen uptake by 6%–12% and resting erythrocyte 2,3-diphophoglycerate (RBC 2,3-DPG) from 13.00 to