, with or without carbohydrate ( Howatson & van Someren, 2008 ). In terms of efficacy, mixed results have been reported for amino acid–based interventions ( Jackman et al., 2010 ; White et al., 2008 ). Hence, evidence is equivocal that amino acid supplementation alone provides an effective strategy for
Jordan D. Philpott, Chris Donnelly, Ian H. Walshe, Elizabeth E. MacKinley, James Dick, Stuart D.R. Galloway, Kevin D. Tipton and Oliver C. Witard
Nancie H. Herbold, Bridget K. Visconti, Susan Frates and Linda Bandini
This study examined the traditional (single and multivitamin/mineral supplements) and nontraditional supplement (herbals, botanicals, and other biologic and nutrient supplements) use by female athletes. Frequency, reasons for use, and sources of supplement information were assessed with a self-report questionnaire. Participants were 162 collegiate female varsity athletes. More than half of all athletes used some type of supplement at least once a month (65.4%). Thirty-six percent (n = 58) of the sample used a multivitamin and mineral with iron. Twelve percent (n = 19) reported amino acid/protein supplement use and 17% (n = 29) used an herbal/botanical supplement. The most frequently cited reason for supplement use was “good health” (60.1%). A major source of information on supplements reported was family (53%). With the general rise in supplement use, nutrition education on the use of traditional and non-traditional supplements is warranted.
Eric T. Trexler and Abbie E. Smith-Ryan
Nutritional supplementation is a common practice among athletes, with creatine and caffeine among the most commonly used ergogenic aids. Hundreds of studies have investigated the ergogenic potential of creatine supplementation, with consistent improvements in strength and power reported for exercise bouts of short duration (≤30 s) and high intensity. Caffeine has been shown to improve endurance exercise performance, but results are mixed in the context of strength and sprint performance. Further, there is conflicting evidence from studies comparing the ergogenic effects of coffee and caffeine anhydrous supplementation. Previous research has identified independent mechanisms by which creatine and caffeine may improve strength and sprint performance, leading to the formulation of multi-ingredient supplements containing both ingredients. Although scarce, research has suggested that caffeine ingestion may blunt the ergogenic effect of creatine. While a pharmacokinetic interaction is unlikely, authors have suggested that this effect may be explained by opposing effects on muscle relaxation time or gastrointestinal side effects from simultaneous consumption. The current review aims to evaluate the ergogenic potential of creatine and caffeine in the context of high-intensity exercise. Research directly comparing coffee and caffeine anhydrous is discussed, along with previous studies evaluating the concurrent supplementation of creatine and caffeine.
Paulo Sugihara Junior, Alex S. Ribeiro, Hellen C.G. Nabuco, Rodrigo R. Fernandes, Crisieli M. Tomeleri, Paolo M. Cunha, Danielle Venturini, Décio S. Barbosa, Brad J. Schoenfeld and Edilson S. Cyrino
evaluate the additive effect of protein supplementation on RT-induced adaptations ( Finger et al., 2015 ; Miller et al., 2014 ; Morton et al., 2018 ; Naclerio & Larumbe-Zabala, 2016 ; Pasiakos et al., 2015 ; Thomas, Quinn, et al., 2016 ). However, there is substantially less information on the topic
Paula J. Ziegler, Judy A. Nelson and Satya S. Jonnalagadda
The present study examined the prevalence of dietary supplement use among elite figure skaters, gender differences in supplement use, and differences in nutrient intake of supplement users versus non-users. Male (n = 46) and female (n = 59) figure skaters completed a supplement survey and 3-day food records. Descriptive analysis, chi-square test, and independent t tests were used to analyze the data. Sixty-five percent of male (n = 30) and 76% of female (n = 45) figure skaters reported use of supplements. Forty-seven percent of males and 55% of females reported daily use of supplements. Multivitamin-mineral supplements were the most popular dietary supplements consumed by figure skaters. Significant gender differences were observed in the use of multivitamin-mineral supplements (61% males vs. 83% females, p < .05). Echinacea and ginseng were popular herbal supplements used by these skaters. The 3 main reasons given by male figure skaters for taking supplements were: to provide more energy (41%), to prevent illness or disease (34%), and to enhance performance (21%). Among female figure skaters, the 3 main reasons given were: to prevent illness or disease (61%), to provide more energy (39%), and to make up for an inadequate diet (28%). Significant differences (p < .05) were observed in protein, total fat, saturated fat, polyunsaturated fat intakes, and % energy from carbohydrate and total fat of male supplement users versus non-users, with supplement users having higher intakes except for percent energy from carbohydrate. Sodium was the only nutrient significantly different (p < .05) among female supplement users versus non-users, with supplement users having lower intakes. Given the popularity of dietary supplements, it is important to understand the factors influencing athletes’ use of supplements, their knowledge and attitudes regarding supplements, dosage of supplements used, and the effectiveness of these dietary supplements in meeting the goals of the athletes.
Jason P. Brandenburg and Luisa V. Giles
altering afferent input to the central nervous system, which may depress central drive to the working muscles ( Reid, 2016 ). Given the involvement of oxidative stress in fatigue, a potential strategy to enhance performance is to augment the endogenous antioxidant defenses via dietary supplementation
Alistair R. Mallard, Rebecca T. McLay-Cooke and Nancy J. Rehrer
Effects of protein versus mixed macronutrient supplementation on total energy intake (TEI) and protein intake during an ad libitum diet were examined. Trained males undertook two, 2-week dietary interventions which were randomized, double blinded, and separated by 2 weeks. These were high-protein supplementation (HP: 1034.5 kJ energy, 29.6 g protein, 8.7 g fat and 12.3 g CHO) and standard meal supplementation (SM: 1039 kJ energy, 9.9 g protein, 9.5 g fat, and 29.4 g CHO) consumed daily following a week of baseline measures. Eighteen participants finished both interventions and one only completed HP. TEI (mean ± SD) was not different between baseline (11148 ± 3347 kJ) and HP (10705 ± 3143 kJ) nor between baseline and SM (12381 ± 3877 kJ), however, TEI was greater with SM than HP (923 ± 4015 kJ p = .043). Protein intake (%TEI) was greater with HP (22.4 ±6.2%) than baseline (19.4 ± 5.4%; p = .008) but not SM (20.0 ± 5.0%). No differences in absolute daily protein intake were found. Absolute CHO intake was greater with SM than HP (52.0 ± 89.5 g, p = .006). No differences in fat intake were found. Body mass did not change between baseline (82.7 ± 11.2 kg) and either HP (83.1 ± 11.7 kg) or SM (82.9 ± 11.0 kg). Protein supplementation increases the relative proportion of protein in the diet, but doesn’t increase the absolute amount of total protein or energy consumed. Thus some compensation by a reduction in other foods occurs. This is in contrast to a mixed nutrient supplement, which does not alter the proportion of protein consumed but does increase TEI.
Lothar Rokitzki, Enno Logemann, Georg Huber, Elfriede Keck and Josef Keul
This study was undertaken to evaluate the effects of 5 months of α-tocopherol supplementation on physical performance during aerobic exercise training in 30 top-class cyclists. Antioxidative effects of supplementation were also studied. Plasma α-tocopherol concentration increased significantly in the vitamin E-supplemented group, whereas the placebo group showed a trend toward decrease. Physical performance did not improve in the α-tocopherol-supplemented group compared to the placebo group. Heart rates were also not significantly different. Lactate concentrations at the aerobic threshold and the anaerobic threshold were identical. Thus, there was no performance improvement in the α-tocopherol-supplemented group. However there was a significant reduction in CK in serum of the E-supplemented group. A trend toward decrease in GOT, GPT, and LDH was observed with α-tocopherol supplementation. Moreover, significantly reduced malondialdehyde serum levels were measured in the E-supplemented group. The findings indicate a protective effect of α-tocopherol supplementation against oxidative stress induced by strenuous exercise.
Angela de Silva, Yasas Samarasinghe, Dhammika Senanayake and Pulani Lanerolle
Intake of dietary supplements is widespread among athletes in developed countries. This study evaluated the use of dietary supplements in athletes from a developing country. Dietary supplementation practices of 113 national-level athletes age 15–35 yr in Sri Lanka were assessed. All athletes from track-and-field, badminton, football, swimming, cycling, and karate squads who consented to participate in the study were administered an anonymous questionnaire by an interviewer. Information on number of supplements taken, frequency of use, nature of product, rationale, sources of advice, and reasons for taking supplements was obtained. Most athletes (94%) consumed dietary supplements. On average, 3.7 products/day were consumed. Footballers had significantly lower intake of supplements than other athletes (footballers 71%, others 98%; p < .05). They also consumed fewer products per day (footballers 0.7, others 3.5; p < .05). Popular supplements included multivitamins, vitamin E, calcium, energy foods and drinks, and creatine. Multiple supplement use was common, with 29% athletes taking 4 products/day. The athletes sought advice on supplement use from sports doctors (45%), team coaches (40%), or friends (15%). Most took supplements to improve performance (79%), and 19% claimed to take supplements to improve their overall health status. Dietary supplement use is widespread among national-level Sri Lankan athletes. The ad hoc use of supplements indicates that educational intervention in the sporting community is essential.
Ronald J. Maughan
In May 2017, the Medical and Scientific Commission of the International Olympic Committee assembled a panel of experts at their offices in Lausanne, Switzerland, to discuss the role of dietary supplements in the life of the high-performance athlete. Participants were selected because of their