Prevalence and patterns of dietary supplement use in elite Spanish athletes

Tribulus terrestris and Sport Performance: A Quantitative and Qualitative Evaluation of Its Advertisement and Availability via Online Shopping in Six Different Countries

Dietary supplements are commonly used among athletes, and the Internet may be an easy source of these products. Tribulus terrestris is an herbal supplement with multiple properties. Of interest to athletes are reports that its consumption can lead to muscle mass gain and a faster recovery process. The objective of this cross-sectional study was to determine the availability of Tribulus terrestris via the Internet in six countries (Canada, Puerto Rico, Russia, Spain, Ukraine, and the United States of America) via a specifically designed computer program. The characteristics of the websites selling this substance, the country from which it can be purchased, the route of administration, and recommendations for its use were analyzed. The results of the study show that this supplement is marketed mainly in Russia, Ukraine, and Spain on many websites that are mostly dedicated to sports products. Just over half of the webpages (59.14%) identified only distribute this supplement within the same country. The main claims for its consumption refer to sports performance benefits, but there are also claims that it may improve male hormone levels and sexual function. Athletes should be encouraged to seek professional advice prior to ingesting this supplement to ensure that it is suitable for their specific training and sports objectives.

Effects of CurraNZ, a New Zealand Blackcurrant Extract during 1 Hour of Treadmill Running in Female and Male Marathon des Sables Athletes in Hot Conditions: Two Case Studies

Four weeks before competition in the 2023 Marathon des Sables, a 6-stage, ~250 km running event in the Sahara Desert, we examined the effects of a 7-day intake of New Zealand blackcurrant extract (210 mg anthocyanins per day) on 1 h treadmill running-induced physiological and metabolic responses in the heat (~34 °C, relative humidity: ~30%) in non-acclimatized amateur female and male athletes (age: 23, 38 yrs, BMI: 24.2, 28.4 kg·m-2, body fat%: 29.2, 18.8%, V˙O2max: 50.1, 52.1 mL·kg-1·min-1). During the 1 h run at 50%V˙O2max (speed female: 7.3, male: 7.5 km·h-1), indirect calorimetry was used, and heart rate was recorded at 15 min intervals with core temperature monitoring (0.05 Hz). The 1 h runs took place 3 h after a light breakfast and 2 h after intake of the final dose of New Zealand blackcurrant extract with water allowed ad libitum during the run. The New Zealand blackcurrant extract had no effects on the female athlete. The respiratory exchange ratio (RER) of the female athlete in the non-supplement control condition was 0.77 ± 0.01, indicating an existing ~77% contribution of fat oxidation to the energy requirements. In the male athlete, during 1 h of running, fat oxidation was higher by 21% (p < 0.01), carbohydrate oxidation was 31% lower (p = 0.05), RER was 0.03 units lower (p = 0.04), and core temperature was 0.4 °C lower (p < 0.01) with no differences for heart rate, minute ventilation, oxygen uptake, and carbon dioxide production for the New Zealand blackcurrant condition compared to the non-supplement control condition. Seven-day intake of New Zealand blackcurrant extract (210 mg anthocyanins per day) provided beneficial physiological and metabolic responses during exertional heat stress by 1 h of indoor (~34 °C) treadmill running in a male Marathon des Sables athlete 4 weeks before competition. Future work is required to address whether New Zealand blackcurrant provides a nutritional ergogenic effect for Marathon des Sables athletes during long-duration running in the heat combined with personalized nutrition.

No additive effect of creatine, caffeine, and sodium bicarbonate on intense exercise performance in endurance-trained individuals

BACKGROUND

Athletes commonly use creatine, caffeine, and sodium bicarbonate for performance enhancement. While their isolated effects are well-described, less is known about their potential additive effects.

METHODS

Following a baseline trial, we randomized 12 endurance-trained males (age: 25 ± 5 years, VO2max: 56.7 ± 4.6 mL kg-1 min-1; mean ± SD) and 11 females (age: 25 ± 3 years, VO2max: 50.2 ± 3.4 mL kg-1 min-1) to 5 days of creatine monohydrate (0.3 g kg-1 per day) or placebo loading, followed by a daily maintenance dose (0.04 g kg-1) throughout the study. After the loading period, subjects completed four trials in randomized order where they ingested caffeine (3 mg kg-1), sodium bicarbonate (0.3 g kg-1), placebo, or both caffeine and sodium bicarbonate before a maximal voluntary contraction (MVC), 15-s sprint, and 6-min time trial.

RESULTS

Compared to placebo, mean power output during 15-s sprint was higher following loading with creatine than placebo (+34 W, 95% CI: 10 to 58, p = 0.008), but with no additional effect of caffeine (+10 W, 95% CI: -7 to 24, p = 0.156) or sodium bicarbonate (+5 W, 95% CI: -4 to 13, p = 0.397). Mean power output during 6-min time trial was higher with caffeine (+12 W, 95% CI: 5 to 18, p = 0.001) and caffeine + sodium bicarbonate (+8 W, 95% CI: 0 to 15, p = 0.038), whereas sodium bicarbonate (-1 W, 95% CI: -7 to 6, p = 0.851) and creatine (-6 W, 95% CI: -15 to 4, p = 0.250) had no effects.

CONCLUSION

While creatine and caffeine can enhance sprint- and time trial performance, respectively, these effects do not seem additive. Therefore, supplementing with either creatine or caffeine appears sufficient to enhance sprint or short intense exercise performance.

Snack and Nutrient Intake Status of Top-Level Female University Athletes: A Cross-Sectional Study

Ensuring proper energy, nutrient intake, and sleep is vital for athlete health and competitiveness. Despite previous studies investigating the nutrient intake among top-level collegiate female athletes in Japan, the status of snack consumption remains unclear. This study addressed this gap by surveying 70 top-level female university athletes. The survey included a self-administered diet history questionnaire, a qualitative food intake frequency survey, and a survey on snack and dietary supplement use. The results revealed a low frequency of snack intake (2.1 ± 2.3 days/week), with 55.7% of athletes reporting snack consumption. The energy intake in the snack-intake group was significantly higher than that in the without-snack-intake group (31.5 ± 10.0 vs. 26.6 ± 9.92 kcal/kg of BM, p = 0.047). Similarly, carbohydrate intake was significantly higher in the snack-intake group than in the without-snack-intake group (4.84 ± 1.71 vs. 3.96 ± 1.65 g/kg of BM/day, p = 0.035). However, neither group reached the recommended value of 5-8 g/kg of BM/day during the medium training period. Overall, this study emphasizes inadequate energy intake even among athletes with a high snack intake frequency, highlighting the necessity to enhance overall food consumption and underscoring the importance of nutritional education for incorporating appropriate complementary meals to improve performance.

Differences in Consumption Behaviour of Dietary Supplements in Competitive Athletes Depends on Sports Discipline

BACKGROUND

The consumption of dietary supplements (DS) is widespread among the general population and competitive athletes. However, only a few competitive athletes seek information from experts about the effects and use of DS. Furthermore, it is currently unknown whether certain sports have a higher affinity for DS than others.

METHODS

This study aimed to identify differences between different sports categories and subgroups that may have a very high affinity for DS. For this purpose, competitive athletes were surveyed. The survey included the type of sport, the training frequency, the number of competitions, the consumption behaviour of five DS categories (general health, regeneration promotion, performance enhancement, booster, and weight loss) as well as personal data such as biological sex and age. Subsequently, correlations, configural frequencies (CFA), and multiple correspondence analyses (MCA) were used to identify subgroups with a high affinity of consumption behaviour.

RESULTS

A total of 409 questionnaires could be evaluated. It was found that all DS categories except weight loss were related. In addition, it was observed that in sports from the power category and from the endurance category, there was even higher consumption behaviour than in other sports categories. Male power athletes in particular have a higher affinity for consuming DS than other subgroups.

CONCLUSIONS

This study shows that there is a clear different consumption behaviour depending on the type of sport. Male power athletes in particular are the subgroup with the greatest consumption behaviour and therefore require special education on the effects and use of DS. This subgroup in particular should receive increased attention in counselling on DS to minimise the possible risks of DS use.

Personality Determinants Related to the Use of Selective and Effective Dietary Supplements by Elite Polish Team Sport Athletes

INTRODUCTION

The purpose of this research was to analyse relationships between personality traits and the use of selected dietary supplements among Polish athletes training in team sports. This subject matter has not been explored in prior research.

MATERIAL AND METHODS

This research was carried out among a group of 213 athletes (men) in the 18-36 age range, with the implementation of a proprietary validated questionnaire for the use of dietary supplements and the NEO-PI-R inventory (Neuroticism-Extraversion-Openness Personality Inventory-Revised). Statistical analyses were performed with the Kruskal-Wallis and Mann-Whitney tests, assuming the following level of significance: α = 0.05.

RESULTS

It was shown that athletes who periodically and regularly consumed isotonic drinks, as well as energy bars and gels, were characterised by a lower level of neuroticism than those who did not consume them. Athletes who periodically took multivitamin preparations were characterised by a lower level of extraversion and openness, and those periodically using multimineral preparations were characterised by a higher level of agreeableness than those who did not use these agents. Athletes not taking creatine were characterised by the lowest level of conscientiousness among the study participants. The use of protein nutrients, probiotics and caffeine was not associated with any personality traits in the athletes.

CONCLUSIONS

Further relationships of the Big Five personality traits were demonstrated with the use of effective dietary supplements by athletes; the most unambiguous correlations were described for neuroticism and conscientiousness in such a way that the use of isotonic drinks, as well as energy bars and gels, was connected with a low level of neuroticism, while the use of creatine was connected with high conscientiousness.

Analysis of Sports Supplement Consumption in 1688 Federated Road Cyclists

The widespread use of sports supplements (SS) to enhance athletic performance extends to cyclists, although little research has been conducted on this subject within this sport. This descriptive and cross-sectional study involved 1688 federated road cyclists, aiming to analyse the pattern of SS consumption concerning the degree of scientific evidence and different categories. This study categorised SS based on the groups and subgroups established by the Australian Sport Institute (AIS, 2023) based on the level of evidence. Our results showed that 62.5% of the sample cyclists used SS, with an average of 12.2 ± 8.6 supplements consumed per participant. Health status (78.2%), pharmacies (62.5%), and medical doctors (45.7%) were the main reasons, purchase sites, and sources of information for SS consumption, respectively. The most prevalent SS consumed were Sports Gels (94%), Sports Bars (89.3%), and Sports Drinks (73.8%). Notably, 80% of the top ten most consumed SS belonged to the group with the highest level of evidence according to the AIS, with an average of 6.9 ± 3.2 supplements per participant. However, 23.3% of the total SS consumers used prohibited substances. In conclusion, while the prevalence of SS consumption among road cyclists is considerable and the primary sources for purchasing SS and obtaining advice are reliable, there is a notable prevalence of prohibited substance use within the sample.

Betalains Alleviate Exercise-Induced Oxidative Stress, Inflammation, and Fatigue and Improve Sports Performance: an Update on Recent Advancement

PURPOSE OF REVIEW

Beetroot juice is a popular natural food supplement commonly consumed for its health and ergogenic benefits. It contains an abundance of phytochemical compounds, which have been shown to enhance sports endurance and recovery. Among them, nitrate is well-studied and known for improving performance during exercise. On the other hand, betalains, the bioactive pigment, have shown various biological activities including antioxidant, anti-inflammatory, and anti-hypertensive, which may improve exercise performance and post-exercise recovery. Additionally, free radical scavenging activities of betalains could increase nitric oxide availability in the blood, thereby improving blood flow and oxygen supply during strenuous exercise. This review article provides a critical discussion of the non-pathological conditions induced by prolonged or strenuous exercise and betalains' potential in reducing such conditions including muscle damage, inflammation, and fatigue. Additionally, the real-time application of betalains as an ergogenic compound in competitive athletes has been discussed. Finally, future directions and conclusions on the potential of betalains as a natural ergogenic aid in sport endurance are outlined.

RECENT FINDINGS

Betalains in beetroot are the major water-soluble nitrogen-containing pigment possessing high antioxidant, anti-inflammatory, and anti-fatigue activities. Betalain supplementation could alleviate exercise-induced oxidative stress, inflammation, and fatigue in competitive athletes. Betalains have the potential to become a natural ergogenic aid or nutraceutical compound for sports people during exercise and competitive performance.

A Behaviourally Informed Approach to Reducing the Risk of Inadvertent Anti-doping Rule Violations from Supplement Use

For many reasons, athletes' use of supplements is highly prevalent across sports and competitive levels, despite the risk of these products containing a substance on the World Anti-Doping Agency Prohibited List. Contravening anti-doping rules through supplement use could have serious consequences for competitive athletes (e.g., ineligibility from major competitions, loss of medals and funding) due to the principle of strict liability. Indiscriminate supplement use also poses a risk to athlete health. To reduce the possibility of ingesting a supplement containing prohibited substances, independent quality assurance and certification programs have been established (e.g., Informed Sport). However, these programs do not completely eliminate risk, leading to some anti-doping organisations promoting a 'just say no' to supplements stance. Yet, this approach can be problematic as a small number of supplements may be necessary for athletes to consume, in certain situations. Recognising that athletes will continue to use these heavily marketed products, this narrative review describes a theoretically underpinned and systematic approach to preventing inadvertent doping by considering the barriers to and enablers of athlete adherence to risk minimisation supplement use guidelines (RMSUG). By outlining a conceptual shift towards a behaviourally informed approach, this review serves to stimulate the development of multifaceted interventions to prevent inadvertent doping through supplement use. Recognising that risk-minimised supplement use involves a myriad of behaviours, the problem of inadvertent doping through supplement use is framed, and research appraised, through the lens of the Behaviour Change Wheel.

Are Supplements Consumed by Middle-Distance Runners Evidence-Based? A Comparative Study between Level of Competition and Sex

BACKGROUND

Middle-distance running events have special physiological requirements from a training and competition point of view. Therefore, many athletes choose to take sport supplements (SS) for different reasons. To date, few studies have been carried out that review supplementation patterns in middle-distance running. The aim of the present study is to analyze the consumption of SS in these runners with respect to their level of competition, sex and level of scientific evidence.

METHODS

In this descriptive cross-sectional study, data was collected from 106 middle-distance runners using a validated questionnaire.

RESULTS

Of the total sample, 85.85% responded that they consumed SS; no statistical difference was found regarding the level of competition or sex of the athletes. With respect to the level of competition, differences were observed in the total consumption of SS (p = 0.012), as well as in that of medical supplements (p = 0.005). Differences were observed between sexes in the consumption of medical supplements (p = 0.002) and group C supplements (p = 0.029).

CONCLUSIONS

Higher-level athletes consume SS that have greater scientific evidence. On the other hand, although the most commonly consumed SS have evidence for the performance or health of middle-distance runners, runners should improve both their sources of information and their places of purchase.

Use of ergogenic aids among Brazilian athletes: a cross-sectional study exploring competitive level, sex and sports

Was investigated ergogenic aids (EAs) used by Brazilian athletes and their association with performance, sex, sports classification, and modality. It identified the main purposes of EAs and their prescription.

Methods

239 athletes of 15 modalities, ranging from regional to international level, answered a survey online.

Results

Highly competitive athletes consumed nutritional and mechanical aids more (OR = 1.96 CI 95% [1.28-2.9]; OR = 1.79 CI 95% [1.29-2.47]), while the use of psychological EAs decreased [OR = 1.66 95% CI (1.18-2.94); p = 0.001]. Male athletes [OR = 1.44 CI 95% (1.11-2.88)] and individual sports practitioners [OR = 1.78 CI 95% (1.02-3.11)] used nutritional aids more. Triathlon athletes had higher nutritional EA use, while soccer athletes had lower. Combat sports athletes had higher pharmacological EA use.

Conclusion

Athletes use nutritional and pharmacological aids more to improve performance and gain lean body mass. Mechanical aids were used for recovery and psychological aids for motivation. Self-prescription is common, especially for pharmacological aids.

The associations between anthropometric characteristics and nutritional parameters in male elite rugby union players

The objective was to analyse the associations between anthropometric characteristics and diet in male rugby players according to the playing position. A cross-sectional study was developed. The forwards had higher body weight (107 kg) and fat mass (FM; 12%) than the backs (87.8 kg and 8.47%, respectively) (p < 0.05). The quality of diet needs to improve (KIDMED value of 5.87 and 6.36 for forwards and backs, respectively). Nutritional imbalances, such as deficits in carbohydrates, fibre, calcium, magnesium and vitamin D, and excess of fats, saturated fatty acid, cholesterol and sugars were found. Carbohydrates and proteins intake were significant associated (p < 0.05) with a minor FM. Forwards with a KIDMED index of less than 8 had a significantly higher FM than those who maintained an optimal diet (p < 0.05). The diet of rugby players should be more in line with dietary recommendations and take into account the player position to optimise sports performance.

Type of Diet and Sports Supplements in Padel Players According to Level of Competition and Sex

Padel is the world's fastest growing racket sport. However, the analysis of the intake of sports supplements in padel players is scarce. The aim of this research was to analyse and compare the type of diet and the use of sports supplements in padel players according to their competition level and sex. A total of 123 players (94 men and 29 women) participated in the study. Subjects were divided according to their sex and competition level. All participants completed an anonymous questionnaire on diet type and nutritional supplement intake. There were differences found in diet type between competition levels. Regarding players' sex, differences in the number of supplements consumed were reported (p < 0.01). Relationships were found between the number of supplements ingested and the perceived effectiveness of supplements with frequency and time of training (p < 0.05). Creatine in men (≈15%) and vitamin complexes (≈10%) in women were the most used supplements. Lower level padel players do not adapt their diet to the physical demands of padel. Male padel players use a greater number of supplements than female padel players. It is important that nutrition specialists advise players to control diets and supplement.

The Effects of Arginine-Based Supplements on Fatigue Levels following COVID-19 Infection: A Prospective Study in Romania

The purpose of this study was to examine the effects of two arginine-based supplements on the fatigue level of patients following the COVID-19 infection. This is a prospective study of the SARS-CoV-2-infected patients divided into two groups (according to family physicians' prescriptions, Group 1 of patients were treated with Astenor Energy^® containing arginine aspartate, B6 vitamin, biotin and magnesium, and Group 2 of patients were treated with Astenor Forte^® containing L-arginine and malic acid). The patients visited their family physicians from October 2021 to January 2022, complaining of physical and/or mental fatigue following the COVID-19 infection. We recorded 505 patients (146 patients in Group 1 and 359 patients in Group 2) and analyzed the fatigue level using the Fatigue Assessment Scale (FAS) through its total (FAS-T), mental (FAS-M) and physical (FAS-P) scores, at baseline and after three months of treatment. There was no difference between the two groups in terms of age (p = 0.265), but more men were included in Group 1 than in Group 2 (p = 0.001). The patients from Group 2 were significantly more likely to be treated at home than those included in Group 1 (89.7% vs. 65.1%, p < 0.0001) because of the lower severity of the COVID-19 infection (asymptomatic or mild: 82.5% vs. 48.7%, p < 0.0001). After 3 months of treatment, patients indicated no fatigue in the higher percentage compared to than at the baseline (68.7% vs. 27.7%), and the fatigue level significantly decreased both in Group 1 (median baseline 33.0 vs. follow-up 17.00, p < 0.0001) and Group 2 (median baseline 25.0 vs. follow-up 17.00, p < 0.0001). These findings suggest that supplements with L-arginine may be proposed as a remedy to restore physical and mental performance affected by the fatigue burden in people with COVID-19 or following the COVID-19 infection.

Do Spanish Triathletes Consume Sports Supplements According to Scientific Evidence? An Analysis of the Consumption Pattern According to Sex and Level of Competition

Background: The use of sports supplements (SS) to improve sports performance is very common in athletes. In the case of triathletes, the physiological characteristics of the sport may require the use of certain SS. Although the consumption of SS is widespread in this sport, very few studies have investigated it thus far. The aim is to analyze the pattern of SS consumption by triathletes according to sex and the competitive level. Methodology: This is a descriptive cross-sectional study on the consumption and habitual use of SS of 232 Spanish-federated triathletes. Data were collected through a validated questionnaire. Results: Overall, 92.2% of the athletes consumed SS, but no significant differences were found in terms of competition level or sex. Yet, significant differences were found regarding the level of competition for total SS (p = 0.021), the total number of Group A supplements from the AIS classification (p = 0.012), and for the ergogenic aids (p = 0.003). The most-consumed SS were bars, sports drinks, sports gels, and caffeine (83.6%, 74.1%, 61.2%, and 46.6%, respectively). Conclusions: The consumption of SS by triathletes is high, and the number of SS consumed rises from the regional to the national and international levels. The four SS most consumed were included in category A of the AIS (greatest scientific evidence).

Dietary supplements and beverages: Knowledge, attitudes, and practices among semi-professional soccer players in KwaZulu-Natal, South Africa

Background

The ingestion of dietary supplements and beverages is prevalent in soccer, at the amateur and professional level. The absence of professional advice at non-professional level makes amateur soccer players susceptible to ingesting unsafe supplements.

Objectives

To determine the knowledge, attitudes and practices of ABC Motsepe League (semi-professional) players in KwaZulu-Natal regarding the use of dietary supplements and beverages.

Methods

Three hundred and forty-three soccer players participated in a cross-sectional study. Knowledge, attitudes and practices were determined using a questionnaire. Researchers visited twelve teams. On the day of the visit to each team, information sheets and questionnaires were given to participants. Questionnaires were collected immediately following completion. Descriptive statistics were used, including means and standard deviations, where applicable. Inferential statistics, Chi-square and binomial tests were used to analyse the results. Statistical significance was set at p < 0.05.

Results

Sports beverages were the most recommended and commonly used, followed by energy beverages. Dietary supplements were the least-known used. Participants used beverages and dietary supplements to assist in providing more energy (67%), improve health (65%) and improve performance (55%) (p<0.001). Seventy-three percent of participants lacked knowledge about the anti-doping policy (p<0.001), with 87% having never attended a workshop on the safe use of supplements and beverages, or anti-doping awareness campaigns (p<0.001). Thirty-eight percent had not heard of the South African Institute for Drug-Free Sport (SAIDS), and 84% were not familiar with the yearly updated World Anti-Doping Agency's (WADA) prohibited list (p<0.001). Of the 59% who did not take dietary supplements or beverages, 75% had insufficient information regarding them (p<0.001), 66% indicated that dietary supplements and beverages were costly (p=0.001), and 55% indicated they did not need dietary supplements and beverages (p=0.32).

Conclusion

There is a need for an educational programme on the safe use of dietary supplements, and sports and energy beverages among KwaZulu-Natal semi-professional soccer players.

Prevalence of dietary supplement consumption among CrossFit practitioners

Purpose

We aimed to verify the prevalence of dietary supplements among CrossFit practitioners (CFPs), considering gender and training status. Still, we aimed to determine the type, reasons, and associated factors of dietary supplement utilization among CFPs.

Methods

This is a cross-sectional, exploratory, and descriptive study with the snowball sampling method. Data were collected through online questionnaires using the Google Forms® tool. We included CFPs aged 18-64 years, from Aug 1, 2020, to Sept 31, 2020. The questionnaire contained questions to assess the prevalence, type, and reasons for supplement use; also, we assessed information about sociodemographic variables and the prevalence of the main chronic morbidities. To analyze aspects of eating behavior and sleep-related parameters, we applied the three-factor eating questionnaire (TFEQ)-R21 and the Pittsburgh Sleep Quality Index questionnaire (PSQI), respectively.

Results

We assessed one hundred twelve (n = 112; 57 men; 55 women) CFPs (28.9 ± 7.64 years old; body mass index (BMI), 25.5 ± 4.83 kg/m2). Eighty-seven (50 men; 37 women; 28.2 ± 6.66 years old; BMI, 25.4 ± 4.55 kg/m2) reported using dietary supplements. Whey protein was the most used supplement (n = 70), followed by creatine (n = 54). Cognitive restraint (a dimension of eating behavior) score was higher in supplement users than in non-users (51.7 ± 18.6 vs. 42.6 ± 20.5; p = 0.040). Sleep-related parameters did not differ between supplement users and non-users. The most associated factors to supplement use were sex (being man; OR, 7.99; p = 0.007), sleep quality (poor; OR, 5.27; p = 0.045), CrossFit level (as prescribed (RX); OR, 4.51; p = 0.031), and cognitive restraint (OR, 1.03; p = 0.029).

Conclusion

The CFPs, especially RX and Elite ones, showed a higher prevalence of supplement utilization. Anabolic-related supplements (i.e., whey protein and creatine) were the most used; moreover, several CFPs used supplements not supported by scientific evidence. Cognitive restraint score was higher in supplement users than in non-users. RX level, being men, and poor sleep quality were associated with supplement utilization. These data draw attention to the necessity of nutritional education for CrossFit coaches and athletes. Broader studies are necessary to confirm our findings.

Dietary Supplements: A Gateway to Doping?

Dietary supplements are widely used among athletes, but many may be unaware of the potential for unintentional doping, especially considering that supplements can often be contaminated with prohibited substances. The reason behind the widespread use of dietary supplements among athletes is often cited as being for the purposes of enhancing health or performance. However, many athletes turn to unreliable sources of information, and often lack knowledge of dietary supplement regulations. The aim of this narrative review is to explore the current research surrounding the psychological constructs (such as norms, attitudes, and beliefs) related to dietary supplement use among athletes that may lead to inadvertent doping. This review also covers possible programme structures that may be effective at preventing inadvertent doping.

Analysis of the Consumption of Sports Supplements in Open Water Swimmers According to the Competitive Level

BACKGROUND

Sports supplements (SS) are widely consumed by many types of athletes to improve their performance. These SS are classified according to their level of scientific evidence, by the ABCD system from the Australian Institute of Sport (AIS). In open water swimming, their use may be necessary due to the physiological challenges posed by this sport discipline. However, there is currently little literature on the use of SS in open water swimmers. The aim of this work is to analyze the pattern of consumption of SS by open water swimmers, by studying the differences according to the competitive level (regional vs. national).

METHODS

Descriptive and cross-sectional study on the consumption and use of SS by federated open water swimmers in Spain in the 2019/2020 and 2020/2021 seasons. The data were collected through a validated questionnaire.

RESULTS

79.5% of the participants consumed SS, with significant differences according to their level, being higher in athletes at the national level. The most-consumed SS by the swimmers studied were sports drinks, energy bars, caffeine, vitamin C, and vitamin D.

CONCLUSIONS

It was observed that the consumption of SS in open water swimmers was high, and of the five most-consumed SS, four of them belonged to the category of greatest scientific evidence.

Anti-Doping Knowledge of Students Undertaking Bachelor's Degrees in Sports Sciences in Spain

In Spain, students pursuing a career in athletic training, physical education, or scientific evaluation of sports enroll in a bachelor’s degree in sports sciences. This degree provides knowledge and skills in a broad array of sports settings and promotes research-based interdisciplinary knowledge. However, the student’s syllabus rarely includes specific academic training on anti-doping regulations or doping prevention. The purpose of this study was to assess the anti-doping knowledge of the students undertaking a bachelor’s degree in sports sciences in Spanish universities. One thousand two hundred and thirty-three bachelor students in sport science (907 males, 322 females, and 4 participants with non-binary sex) from 26 Spanish universities completed a validated questionnaire about general anti-doping knowledge. The questionnaire is an adapted version of the Play True Quiz of the World Anti-Doping Agency and contains 37 multiple-choice questions. The score obtained in the questionnaire was transformed into a 0−100-point scale. The questionnaire was distributed among students within each university by a faculty member and it was filled out online. Students obtained a score of 65.8 ± 10.10 points (range = 32−92 points). There was an effect of the course in the score obtained (p < 0.001). Students of the first course (63.6 ± 9.5 points) had lower scores than the remaining courses (p < 0.037) while the students of the fourth course obtained the highest scores (68.7 ± 9.5 points; p < 0.019). The students with an itinerary on sports performance were the respondents with the highest anti-doping knowledge (67.2 ± 10.2) points, followed by the students with an itinerary on health (66.7 ± 9.5 points). The knowledge of basic anti-doping rules and doping prevention strategies of the bachelor students in sports sciences in Spain was suboptimal. Increasing doping prevention information in the syllabus of the bachelor’s degree in sports sciences is essential as these future professionals will directly work with populations at risk of doping.

Sports Supplements User Profile Based on Demographic, Sports, and Psychological Variables: A Cross-Sectional Study

Despite the high prevalence of sports supplement (SS) use, efforts to profile users have not been conclusive. Studies report that 30–95% of recreational exercisers and elite athletes use SS. Research found has mostly focused on demographic and sports variables to profile SS users, but little research has studied the psychological factors that may influence the use of SS. The purpose of this investigation was to classify, describe, and differentiate the profile of users and non-users of SS, considering demographic, sports, and psychological variables. A total of 554 participants completed the questionnaire. Overall, 45% of recreational exercisers and elite athletes reported using supplements. There were significant differences found regarding the use of SS between men and women (51% vs. 49%, p = 0.002; OR = 1.799), and when training 4 or more days per week (p ≤ 0.001; OR = 1.526). Findings regarding the psychological variables have been found in the Adonis Complex. These results indicate that participants with greater concerns regarding physical appearance, tend to be SS users (p = 0.001; OR = 1.200). The results of this study fill a gap in previous research, and provide an approximate profile, including demographic, sports, and psychological variables of SS users.

Prevalence of Dietary Supplement Use among Athletes Worldwide: A Scoping Review

Athletes represent a major part of dietary supplement users. This scoping review aims to explore the prevalence of dietary supplement use among athletes worldwide, most commonly used supplements, sources of information on dietary supplements and their reasons for use of these supplements. PubMed, CINAHL, MEDLINE, and PsycInfo were searched for original research articles. Studies were included if they involved athletes, identified the prevalence of dietary supplement use, and were published after 2017. A total of 26 articles were reviewed. Prevalence of dietary supplement use varied among articles, but sex-based differences related to the types of used dietary supplements existed. Generally, the findings were consistent in terms of reasons for use and sources of information. Unfortunately, the lack of homogeneity regarding the definition of dietary supplements, definition of use, reporting timeframes, and data collection methods complicates the attempt to compare the findings among studies.

Prevalence, patterns, and attitude regarding dietary supplement use in Saudi Arabia: Data from 2019

Dietary supplements are products containing dietary elements including vitamins, minerals, amino acids, herbs, or botanicals. They can aid consumers with low dietary intake and quality, as well as those with high demands, by boosting nutritious value. A cross-sectional study was conducted among adults living in Saudi Arabia aged between 18–60 years old using online self-administered questionnaire. Information regarding sociodemographic characteristics, use and type of dietary supplements, and attitude toward and patterns of dietary supplement use was collected. The chi-square test, Pearson correlations, and the independent t-test were used. In total, 531 participants (115 men and 416 women) were included. Approximately half of the participants (51.8%, n = 275) used dietary supplements. Participants who were using dietary supplements were significantly younger (29.16 ± 9.32 years), more highly educated (85.5%, n = 235), and worked in the health sector (63.7%, n = 100). Herbal supplement use was associated with older age and female sex. Single mineral supplements were used more frequently by married, female, pregnant, or breastfeeding participants and those not working in the health sector. Fatty supplements were used more frequently by participants with a higher level of education. Regarding the attitude toward dietary supplement use, women, single participants, and health care workers showed a significant positive attitude. In-depth investigation into the amount of and reasons for dietary supplement use in the health sector is required. Additionally, educating pregnant and breastfeeding women on the importance of dietary supplements is necessary.

Dietary Supplement Use of Turkish Footballers: Differences by Sex and Competition Level

This study aimed to evaluate the consumption of dietary supplements (DS) and to determine related topics in Turkish football players of different sexes and competition levels. A total of 117 footballers (79 males and 38 females) completed a specific survey regarding DS consumption in athletes. The type of DS ingested was classified based on the level of scientific evidence by the Australian Institute of Sport (AIS): group A (high level of scientific evidence), group B (DS that could have a positive effect, but require more evidence), group C (evidence is against their use), and group D (prohibited substances). After a Kolmogorov−Smirnov test, a t-test or Mann−Whitney U test was performed for quantitative variables, while Pearson’s chi-square and odds ratio (with the confidence interval) were performed for qualitative variables. Of the sample, 87.2% reported having consumed DS, with a higher consumption rate in males (males: 93.7%, females: 73.7%; p = 0.006; OR = 5.3 [1.7−16.8]) and professional players (professional: 98.2%, non-professional: 77.4%; p < 0.001; OR = 7.9 [1.2−52.3]). Males and professional players consume more sports foods (p < 0.001), performance supplements (p < 0.001), and total group A supplements (p < 0.001) compared to females and non-professionals. In addition, males consume more medical supplements (p = 0.012) and total group C supplements (p < 0.001) than female footballers. The most consumed DS were sports drinks (63.2%), magnesium (52.1%), vitamin C (51.3%), vitamin D (46.2%), caffeine (38.5%), sports bars (37.6%), whey protein (28.2%), meat protein (25.6%), vitamin E (24.8%), and omega-3 fatty acids (24.8%). The supplement consumption was higher in male and professional footballers. According to the AIS classification, there were significant differences in the consumption of sports foods, medical supplements, performance supplements, and the total number of group A and group C supplements according to sex, and there were significant differences in the consumption of sports foods, performance supplements, and the total number of group A supplements according to competition level.

Effects of Citrulline Supplementation on Different Aerobic Exercise Performance Outcomes: A Systematic Review and Meta-Analysis

Supplementation with Citrulline (Cit) has been shown to have a positive impact on aerobic exercise performance and related outcomes such as lactate, oxygen uptake (VO₂) kinetics, and the rate of perceived exertion (RPE), probably due to its relationship to endogenous nitric oxide production. However, current research has shown this to be controversial. The main objective of this systematic review and meta-analysis was to analyze and assess the effects of Cit supplementation on aerobic exercise performance and related outcomes, as well as to show the most suitable doses and timing of ingestion. A structured literature search was carried out by the PRISMA^® (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and PICOS guidelines in the following databases: Pubmed/Medline, Scopus, and Web of Science (WOS). A total of 10 studies were included in the analysis, all of which exclusively compared the effects of Cit supplementation with those of a placebo group on aerobic performance, lactate, VO₂, and the RPE. Those articles that used other supplements and measured other outcomes were excluded. The meta-analysis was carried out using Hedges’ g random effects model and pooled standardized mean differences (SMD). The results showed no positive effects of Cit supplementation on aerobic performance (pooled SMD = 0.15; 95% CI (−0.02 to 0.32); I², 0%; p = 0.08), the RPE (pooled SMD = −0.03; 95% CI (−0.43 to 0.38); I², 49%; p = 0.9), VO₂ kinetics (pooled SMD = 0.01; 95% CI (−0.16 to 0.17); I², 0%; p = 0.94), and lactate (pooled SMD = 0.25; 95% CI (−0.10 to 0.59); I², 0%; p = 0.16). In conclusion, Cit supplementation did not prove to have any benefits for aerobic exercise performance and related outcomes. Where chronic protocols seemed to show a positive tendency, more studies in the field are needed to better understand the effects.

The Effects of Consuming Amino Acids L-Arginine, L-Citrulline (and Their Combination) as a Beverage or Powder, on Athletic and Physical Performance: A Systematic Review

Consumption of amino acids L-arginine (L-Arg) and L-citrulline (L-Cit) are purported to increase nitric oxide (NO) production and improve physical performance. Clinical trials have shown relatively more favorable outcomes than not after supplementing with L-Cit and combined L-Arg and L-Cit. However, in most studies, other active ingredients such as malate were included in the supplement. Therefore, the aim of this study was to determine the efficacy of consuming standalone L-Arg, L-Cit, and their combination (in the form of powder or beverage) on blood NO level and physical performance markers. A systematic review was undertaken following PRISMA 2020 guidelines (PROSPERO: CRD42021287530). Four electronic databases (PubMed, Ebscohost, Science Direct, and Google scholar) were used. An acute dose of 0.075 g/kg of L-Arg or 6 g L-Arg had no significant increase in NO biomarkers and physical performance markers (p > 0.05). Consumption of 2.4 to 6 g/day of L-Cit over 7 to 16 days significantly increased NO level and physical performance markers (p < 0.05). Combined L-Arg and L-Cit supplementation significantly increased circulating NO, improved performance, and reduced feelings of exertion (p < 0.05). Standalone L-Cit and combined L-Arg with L-Cit consumed over several days effectively increases circulating NO and improves physical performance and feelings of exertion in recreationally active and well-trained athletes.

Analysis of Sport Supplement Consumption by Competitive Swimmers According to Sex and Competitive Level

Sports supplements (SS) are commonly used by athletes to improve their performance. SS use by competitive swimmers is reported to be prevalent but there is no evidence of such use by elite swimmers, either male or female. The objective of this research was to study the patterns of SS use by competitive swimmers based on sex and competitive levels (national and international); Methods: Using the categories of the Australian Institute of Sport (AIS), a total of 102 competitive swimmers (59 men and 43 women) completed a validated self-administered questionnaire on the use of SS; (3) Results: Overall, 86.9% of swimmers had consumed SSs with no differences observed between males and females (p = 0.247) or between competitive levels (p = 0.597). The SS that were most consumed by swimmers were caffeine (53.5%), sport drinks (52.5%), sport bars (51.5%), and vitamin C (43.4%). SSs categorized as medical supplements were consumed significantly more frequently by international swimmers (p = 0.012), with significant differences also found in the level—sex interaction (p = 0.049); (4) Conclusions: Compared to other sports disciplines, the prevalence of SS consumption is high in competitive swimmers regardless of performance level or gender. However, the consumption of medical supplements was greater in swimmers at a higher performance level.

Measured versus label declared macronutrient and calorie content in Colombian commercially available whey proteins

Whey protein (WP) supplements have grown in popularity for exercising populations to enhance muscle protein synthesis and promote recovery. The purpose of this investigation was to examine the macronutrient profile, especially protein, of commonly sold protein powder brands in the Colombian (South America) sports supplement market. Eleven popular whey proteins supplements made and sold on the Colombian market were sampled and determined the humidity, ash, total carbohydrates, fat, proteins, and calories (kcal). The mean calorie content declared by product labeling was significantly lower (p < 0.05) than measured (labeled 349.8 ± 20.3 kcal; analyzed 368.2 ± 14.9 kcal). Carbohydrate content was higher than labeled on average (labeled 3.5 ± 6 g/100 g; analyzed 21.9 ± 12.5 g/100 g) (p < 0.05). The protein content on the labels showed a significantly higher content, on average, than analyzed in all samples (labeled 81.4 ± 7.4; analyzed 65.7 ± 14.1) (p < 0.05). These data suggest, that for brands analyzed in this research, nutrient labels may be misleading, especially regarding protein, carbohydrate, and total calorie content. Consumers should diligently read, but also learn the different product labeling; however, brands should emphasize on testing their products and add amino acid profiles to guarantee quality of their products.

Herbs as an Active Ingredient in Sport: Availability and Information on the Internet

The use of supplements containing herbal active ingredients in sport has increased in recent years. Their consumption is explained by the benefits they may provide and because their natural origin do not involve health complications, from the point of view of the consumers. The aim of this study is to analyze the availability of four supplements (caffeine, turmeric, ginseng, cannabidiol) on the internet and understand the nature of these websites. A descriptive, observational, and cross-sectional study design was used. A detailed search was carried out with specifically developed software. The searches and data evaluation took 10 days. The websites consulted correspond to those that sell supplements, or some sport websites in the case of the Spanish ones, whereas those in English belong to pharmacies, parapharmacies, or herbalists. It is concluded that the websites do not provide adequate information to ensure proper consumption and lack advice on the choices of supplements and their administration guidelines.

Dietary practices and supplement use among CrossFit® participants

Background

CrossFit® is a popular high-intensity functional training program. CrossFit® participants may practice popular diets or consume dietary and sports supplements to support their health or physical pursuits, but the specific dietary and supplement practices of CrossFit® participants remain unknown.

Methods

An electronic questionnaire was developed to collect data on practice of popular diets (i.e. Paleo and The Zone Diet®), dietary and sports supplement use, reasons for practicing a diet or using supplements, sources of information on diets and supplements, and various beliefs associated with nutrition among CrossFit® participants.

Results

Of the 2,576 complete responses (female 51.9%, male 48.1%, age 39.4 ± 11.1 years, body mass index 26.1 ± 3.9 kg/m²), 695 (27%) reported being a CrossFit® trainer or coach and 1,392 (54%) reported competing, or planning to compete, in CrossFit® or other fitness competitions. The average years of CrossFit® experience were 5.3 ± 3.1 years, and the average frequency of CrossFit® participation was 4.5 ± 1.1 days/week. Most participants (60.1%) reported practicing a particular diet. Macro Counting (18.6%), Intermittent Fasting (7.7%), and Paleo (6.1%) were the most frequently reported diets. The top reasons for practicing a diet were to improve overall health (45.6%), decrease body fat (29.2%), and improve CrossFit® performance (25.2%). The top sources of dietary information were the Internet (47.5%), coach/trainer (28.7%), and nutritionist/dietitian (26.2%). Most participants (67.3%) reported “Urine Color” as the best method to assess hydration. Additionally, most participants (82.2%) consumed at least one supplement, with protein (51.2%), creatine (22.9%), and pre-workout/energy (20.7%) being most popular. The top reasons for consuming supplements were to improve recovery (52.6%), improve overall health (51.4%), and increase muscle mass/strength (41.7%). The top sources of information on supplements were the Internet (53.1%), coach/trainer (27.0%), and peer-reviewed research (23.0%).

Conclusions

A large proportion of CrossFit® participants may practice popular diets or consume supplements with the intention of improving health or performance. These findings may support future research on the effects of various dietary patterns and supplements on CrossFit® performance.

The Impact of Supplements on Sports Performance for the Trained Athlete: A Critical Analysis

ABSTRACT

Elite athletes often use nutritional supplements to improve performance and gain competitive advantage. The prevalence of nutrient supplementation ranges from 40% to 100% among trained athletes, yet few athletes have a trusted source of information for their supplement decisions and expected results. This critical analysis review evaluates systematic reviews, meta-analyses, randomized control trials, and crossover trials investigating commonly used supplements in sport: caffeine, creatine, beta-alanine (β-alanine), branched chain amino acids (BCAAs), and dietary nitrates. By reviewing these supplements' mechanisms, evidence relating directly to improving sports performance, and ideal dosing strategies, we provide a reference for athletes and medical staff to personalize supplementation strategies. Caffeine and creatine impact power and high-intensity athletes, β-alanine, and BCAA mitigate fatigue, and dietary nitrates improve endurance. With each athlete having different demands, goals to maximize their performance, athletes and medical staff should collaborate to personalize supplementation strategies based on scientific backing to set expectations and potentiate results.

Dietary Supplements Use among Athletes in Lebanon: Knowledge, Attitudes, Practices, and Correlates

Athletes are under the utmost pressure to reach excellence in their performance and achieve the desired outcomes in competitions, prompting them to use dietary supplements. Given the threats to both health and eligibility, it is crucial to observe the prevalence, sources of information, knowledge, attitudes, and practices (KAPs) among Lebanese athletes practicing their sports for at least two years. In the present paper, a cross-sectional study is performed using the snowball sampling method, in which a self-administered KAP questionnaire is used to collect data from 455 athletes (mean age: 27.4 ± 7.9 years; men: 73.1%) participating in four sports categories (ball games, combat sports, endurance sports, and weightlifting). Among the Lebanese athletes, the prevalence of dietary supplement (DS) use was 74%, where half of them had predominately used sports supplements. Athletes in Lebanon heavily rely on coaches (74%) and online sources, including webpages and social media (64%), as key information sources for DSs. The findings suggest that significant proportions of athletes show knowledge deficits and unsatisfactory attitudes towards multiple aspects related to supplementation. Moreover, education and sports type modulate the use of DSs among athletes. Furthermore, 34% reported using supplements without a recommendation from specialists, and 69% admitted to not reading the supplement's nutrition facts. This study urges the need for the regulation of concerned authorities and education programs to help overcome the existing challenges.

Caffeine Supplementation Strategies Among Endurance Athletes

Caffeine is widely accepted as an endurance-performance enhancing supplement. Most scientific research studies use doses of 3–6 mg/kg of caffeine 60 min prior to exercise based on pharmacokinetics. It is not well understood whether endurance athletes employ similar supplementation strategies in practice. The purpose of this study was to investigate caffeine supplementation protocols among endurance athletes. A survey conducted on Qualtrics returned responses regarding caffeine supplementation from 254 endurance athletes (f = 134, m =120; age = 39.4 ± 13.9 y; pro = 11, current collegiate athlete = 37, recreational = 206; running = 98, triathlon = 83, cycling = 54, other = 19; training days per week = 5.4 ± 1.3). Most participants reported habitual caffeine consumption (85.0%; 41.2% multiple times daily). However, only 24.0% used caffeine supplements. A greater proportion of men (31.7%) used caffeine supplements compared with women (17.2%; p = 0.007). Caffeine use was also more prevalent among professional (45.5%) and recreational athletes (25.1%) than in collegiate athletes (9.4%). Type of sport (p = 0.641), household income (p = 0.263), education (p = 0.570) or working with a coach (p = 0.612) did not have an impact on caffeine supplementation prevalence. Of those reporting specific timing of caffeine supplementation, 49.1% and 34.9% reported consuming caffeine within 30 min of training and races respectively; 38.6 and 36.5% used caffeine 30–60 min before training and races. Recreational athletes reported consuming smaller amounts of caffeine before training (1.6 ± 1.0 mg/kg) and races (2.0 ± 1.2 mg/kg) compared with collegiate (TRG: 2.1 ± 1.2 mg/kg; RACE: 3.6 ± 0.2 mg/kg) and professional (TRG: 2.4 ± 1.1 mg/kg; RACE: 3.5 ± 0.6 mg/kg) athletes. Overall, participants reported minor to moderate perceived effectiveness of caffeine supplementation (2.31 ± 0.9 on a four-point Likert-type scale) with greatest effectiveness during longer sessions (2.8 ± 1.1). It appears that recreational athletes use lower caffeine amounts than what has been established as ergogenic in laboratory protocols; further, they consume caffeine closer to exercise compared with typical research protocols. Thus, better education of recreational athletes and additional research into alternative supplementation strategies are warranted.

Dietary Supplements as a Major Cause of Anti-doping Rule Violations

Dietary supplements encompass a large heterogenic group of products with a wide range of ingredients and declared effects used by athletes for a multitude of reasons. The high prevalence of use across all sports and level of competition, combined with the well-documented risks of such products containing prohibited substances have led to several doping cases globally. Despite being a considerable concern and persistent focus of sport organizations and anti-doping agencies, the magnitude of anti-doping rule violations associated with supplement use is not well-known. This study examines 18-years of doping controls of a national anti-doping program to determine the relationship between the presence of prohibited substances in athlete's doping samples and the use of dietary supplements. In 26% (n = 49) of all the analytical anti-doping rule violation cases in the period 2003–2020 (n = 192), the athlete claimed that a dietary supplement was the source of the prohibited substance causing an adverse analytical finding. Evidence supporting this claim was found in about half of these cases (n = 27, i.e., 14% of all analytical ADRV's). Stimulants were the most prevalent substance group linked to supplements (n = 24), of which methylhexanamine was associated with 16 cases. High risk products were predominantly multi-ingredient pre-workout supplements (n = 20) and fat-burning products (n = 4). Anti-doping organizations should develop strategies on how to assist athletes to assess the need, assess the risk and assess the consequences of using various dietary supplements.

Specialized nutrition for athletes: evaluation of ergogenic action using the principles of evidence-based medicine

The aim is to form a balanced position regarding the ergogenic characteristics of new sports food products in the modern practice of training highly qualified athletes on the basis of clinical-experimental evaluation of the effectiveness of special purpose real food additives.

Materials and methods. Studies were carried out on laboratory animals (36 Wistar rats at the age of 3 months weighing 150–200 g and 16 Svetlogorsk mini-pigs) as well as on 102 high-qualified representatives of cyclic sports (all men aged 19–26) − members of national teams such as swimming (25), cross-country athletics (53), and skiing (24). As a control group, we studied 25 athletes of the same gender (all men), age and qualifications who received a placebo (starch capsules) for a long time during exercise. Placebo-controlled studies have been conducted on laboratory animals and athletes in compliance with the principles of bioethics.

Results. It has been established that in the experiment the application of a new specialized food product MioActiv has a positive effect on the physical performance of animals and delays the onset of fatigue, which significantly exceeds the corresponding characteristics in the placebo group. Athletes also showed an increase in speed when passing competitive distances by 18.7–21.4% (p &lt; 0,05), as well as a significant increase in mental endurance indicators (p &lt; 0,05). The approbation of the innovative pre-workout pharmacological nutrient complex Pre-Fuse also showed the high efficacy and safety of this product with a positive effect of increasing the performance and endurance of animals, as well as the parameters of mental performance of athletes in the main groups, in contrast to the data in the placebo control groups.

Conclusions. An analysis of the prescription components of new types of ergogenic sports nutrition and the presented results of preclinical and clinical studies conducted on the basis of the evidence-based medicine paradigm regarding the effectiveness of specialized products indicate the complex action of these funds on various aspects of both physical and mental performance. From the materials presented in the article, it can be seen that specialized sports nutrition products of an ergogenic orientation can provide significant assistance in increasing sports results.

Morning versus Evening Intake of Creatine in Elite Female Handball Players

A great deal of evidence has been gathered on the use of creatine as an ergogenic supplement. Recent studies show greater benefits when creatine ingestion is performed close in time to training, but few studies tackle the way that circadian rhythms could influence creatine consumption. The aim of this study was therefore to observe the influence circadian rhythms exert on sports performance after creatine supplementation. Our method involved randomly assigning fourteen women players of a handball team into two groups in a single-blind study: one that consumed the supplement in the morning and one that consumed it in the evening, with both groups following a specific training program. After twelve weeks, the participants exhibited a decreased fat percentage, increased body weight and body water, and improved performance, with these results being very similar in the two groups. It is therefore concluded that, although circadian rhythms may influence performance, these appear not to affect creatine supplementation, as creatine is stored intramuscularly and is available for those moments of high energy demand, regardless of the time of day.

The prevalence and practices of caffeine use as an ergogenic aid in English professional soccer

The ergogenic properties of caffeine are well established, with evidence supporting beneficial effects for physical and technical elements of performance required for successful soccer match play. Despite this, recommended caffeine practices for professional soccer have not been established. Therefore, the present study aimed to evaluate the use and behaviours surrounding caffeine use in elite English soccer clubs. Representatives of 36 clubs from the top four tiers of English professional football (40%) completed an online survey that sought to determine if, when, how and why caffeine was prescribed to players as a means of improving sports performance. Of the clubs sampled, 97% indicated that caffeine is provided to players as a means of improving performance. Caffeine is most commonly administered prior to (> 94%) and during a game (> 48%), with frequency uninfluenced by time of matches. There was a broad range and lack of consistency in the timing, dose and mode of caffeine administration, but doses were typically low. Evidence from the present study indicate a translational gap between science and practice, highlighting a need for future work to better understand how caffeine consumption can be optimised with respect to the specific demands and constraints in professional soccer.

Gender Differences in Prevalence and Patterns of Dietary Supplement Use in Elite Athletes

Purpose: Dietary supplement use by athletes has been the topic of previous research; however, the lack of homogeneity among published studies makes it difficult to analyze the differences, if any, in the patterns of use between male and female athletes. The aim of this study was to determine gender differences in the patterns of dietary supplement use by elite athletes. Methods: A total of 504 elite athletes (329 males and 175 females) participating in individual and team sports completed a validated questionnaire on dietary supplement use during the preceding season. The dietary supplements were categorized according to the latest IOC consensus statement. Results: A higher proportion of male versus female athletes (65.3 versus 56.5%, p < .05) consumed dietary supplements. Both male and female athletes reported a similar mean consumption of dietary supplements (3.2 ± 2.1 versus 3.4 ± 2.3 supplements/season, respectively; p = .45). Protein supplements were the most commonly consumed supplements in male athletes (49.8%) and their prevalence was higher than in female athletes (29.3%, p < .01). In females, multivitamins (39.4%) and branched-chain amino acids (39.4%) were the most commonly consumed supplements and iron supplementation was more prevalent than in males (22.2% versus 10.2%, p = .01). A higher proportion of male athletes relied on themselves to plan dietary supplements use (48.0%), while female appeared to rely more on doctors (34.0%, p < .01). Conclusion: In summary, male athletes had a slightly higher prevalence in the use of supplements than their female counterparts, specifically regarding protein supplements, and were more involved in the self-prescription of supplements.

Nutrition in Cycling

Cycling is predominantly an endurance sport in which fuel utilization for energy production relies on the availability and delivery of oxygen to exercising muscle. Nutrition and training interventions to improve endurance performance are continually evolving, but ultimately, prescription should aim to generate improvements in cycling power and velocity while prioritizing athlete health and well-being. The wide range of cycling events and the different environments in which events take place pose a variety of nutrition-related challenges for cyclists. This review addresses some of these challenges and highlights recent advancements in nutrition for cycling performance.

The Effects of 6 Weeks of Tribulus terrestris L. Supplementation on Body Composition, Hormonal Response, Perceived Exertion, and CrossFit® Performance: A Randomized, Single-Blind, Placebo-Controlled Study

Tribulus terrestris L. (TT) supplementation have been shown to enhance sports performance in many but not all studies. Moreover, data regarding the potential impact of TT supplementation on CrossFit® endurance is limited. This study aimed to determine whether TT supplementation improve body composition, hormonal response, and performance among CrossFit® athletes. In a randomized, single-blind, placebo-controlled trial, a total of 30 healthy CrossFit®-trained males were randomly allocated to receive either 770 mg of TT supplementation or a placebo daily for 6 weeks. Body mass, fat mass, fat composition, testosterone and cortisol levels, and CrossFit® performance (5 common Workouts of the Day: back squat, bench press, dead lift, Grace, and CrossFit® Total) were assessed before and after intervention. There were no significant group x time interactions for the outcomes of the study except for testosterone levels and bench press performance (p < 0.05). TT supplementation did not impact enhance performance or body composition in CrossFit® male athletes. However, TT supplementation may act as a testosterone booster helping the recovery after physical loads and mitigating fatigue.

Education Interventions to Improve Knowledge, Beliefs, Intentions and Practices with Respect to Dietary Supplements and Doping Substances: A Narrative Review

The misuse of dietary supplements and doping substances is commonly associated with toxicity, nutritional imbalances, and health and psychological consequences. This is alarming especially in light of the increasing prevalence of the use of dietary supplements and doping, particularly among young adults including athletes. There is evidence that education interventions can lead to improved knowledge, intentions, and practices. However, no review has summarized and evaluated the effectiveness of such interventions. The aim of this article is to review the characteristics, contents and effects of education interventions that were designed and implemented to improve knowledge, attitudes, beliefs and intentions with respect to the use of dietary supplements and doping agents in different populations. PubMed, Scopus, CINAHL, PsycInfo and Google Scholar were searched for English-language education interventions targeting dietary supplements and doping substances. A total of 20 articles were identified and have generally provided consistent findings. Most interventions reported a significant improvement in knowledge on dietary supplements and doping agents. Unfortunately, the heavy reliance on self-reported assessment tools limits the validity of these interventions, with almost all articles targeting athletes and adolescents.

Supplement intake in half-marathon, (ultra-)marathon and 10-km runners - results from the NURMI study (Step 2)

The primary nutritional challenge facing endurance runners is meeting the nutrient requirements necessary to optimize the performance and recovery of prolonged training sessions. Supplement intake is a commonly used strategy by elite and recreational distance runners to meet nutritional recommendations. This study was conducted to investigate the patterns of supplement intake among different groups of distance runners and the potential association between supplement intake and sex, age, running and racing experiences.In a cross-sectional design, from a total of 317 runners participating in this survey, 119 distance runners were involved in the final sample after data clearance, assigned into three groups of 10-km runners (n = 24), half-marathoners (n = 44), and (ultra-)marathoners (n = 51). Personal characteristics, training and racing experiences, as well as patterns of supplement intake, including type, frequency, and dosage, were evaluated by questionnaire. Food Frequency Questionnaire was implemented to assess macronutrient intake. ANOVA and logistic regression were used for statistical analysis.While 50 % of total distance runners reported consuming supplements regularly, no differences between distance groups in consumption of carbohydrate/protein, mineral, or vitamin supplements were observed (p > 0.05). In addition, age, sex, running and racing experience showed no significant association with supplement intake (p > 0.05). Vitamin supplements had the highest intake rate in runners by 43 % compared to minerals (34 %) and carbohydrate/protein supplements (19 %).The present findings provide a window into the targeted approaches of long-distance runners as well as their coaches and sport nutrition specialists when applying and suggesting sustainable nutritional strategies for training and competition.Trial registration: ISRCTN73074080. Retrospectively registered 12th June 2015.

Belief in caffeine's ergogenic effect on cognitive function and endurance performance: A sham dose-response study

This study aimed to determine if belief in caffeine's ergogenic potential influences choice reaction time (CRT) and/or running performance. Twenty-nine healthy individuals (23.7 ± 5 years, 16 males) completed two trials (one week apart). Before the trials, participants indicated their "belief" in caffeine's ergogenic effects and previous "experience" using caffeine for performance. On arrival, participants randomly received either sham "Low (100mg; LD)" or "High (300mg; HD)" dose caffeine capsules 30-min before commencing the CRT test, followed by a 10km run. Paired samples t-tests determined differences between trials for CRT latency (Ex-Gaussian analysis; μ-, σ- and τ-) and running performance using the entire cohort and sub-groups exhibiting strong "beliefs"+/-"experience". Sham caffeine dose did not influence CRT (μ-, σ- and τ-respectively, LD: 400 ± 53ms vs. HD: 388 ± 41ms; LD: 35 ± 18ms vs. HD: 34 ± 17ms; LD: 50 ± 24ms vs. HD: 52 ± 19ms, all p's > 0.05). Neither belief (n = 6), nor belief + experience (n = 4), influenced this effect. Furthermore, caffeine dose did not influence run time (LD: 49.05 ± 3.75min vs. HD: 49.06 ± 3.85min, p = 0.979). Belief (n = 9) (LD: 48.93 ± 3.71min vs. HD: 48.9 ± 3.52min, p = 0.976), and belief + experience (n = 6) (LD: 48.68 ± 1.87min vs. HD: 49.55 ± 1.75min, p = 0.386) didn't influence this effect. A dose-response to sham caffeine ingestion was not evident on cognitive or endurance performance in healthy individuals, regardless of their convictions about caffeine's ergogenicity.

Sex Differences in Supplement Intake in Recreational Endurance Runners-Results from the NURMI Study (Step 2)

It has been well-documented that female and male athletes differ in many physiological and psychological characteristics related to endurance performance. This sex-based difference appears to be associated with their nutritional demands including the patterns of supplement intake. However, there is a paucity of research addressing the sex differences in supplement intake amongst distance runners. The present study aimed to investigate and compare supplement intake between female and male distance runners (10 km, half-marathon, (ultra-)marathon) and the potential associations with diet type and race distance. A total of 317 runners participated in an online survey, and 220 distance runners (127 females and 93 males) made up the final sample after a multi-stage data clearance. Participants were also assigned to dietary (omnivorous, vegetarian, vegan) and race distance (10-km, half-marathon, marathon/ultra-marathon) subgroups. Sociodemographic characteristics and the patterns of supplement intake including type, frequency, dosage, and brands were collected using a questionnaire. One-way ANOVA and logistic regression were used for data analysis. A total of 54.3% of female runners and 47.3% male runners reported consuming supplements regularly. The frequency of supplement intake was similar between females and males (generally or across dietary and distance subgroups). There was no significant relationship for sex alone or sex interactions with diet type and race distance on supplement intake (p < 0.05). However, a non-significant higher intake of vitamin and mineral (but not CHO/protein) supplements was reported by vegan and vegetarian (but not by omnivorous) females compared to their male counterparts. In summary, despite the reported findings, sex could not be considered as a strong modulator of supplement intake among different groups of endurance runners.

Supplement Intake in Recreational Vegan, Vegetarian, and Omnivorous Endurance Runners-Results from the NURMI Study (Step 2)

Nutrient deficiency is a common cause of underperformance in endurance athletes, and supplement intake is frequently considered compensatory for vegan and vegetarian athletes specifically. This study aimed to investigate the patterns of supplement intake among vegan, vegetarian, and omnivorous distance (>10 km) runners and its association with age, sex, and race distance. From a total of 317 runners who participated in an online survey, 220 distance runners (mean age: 38.5 years; mean BMI: 21.75 kg/m²) were selected for the final sample after data clearance and assigned to 100 omnivores, 40 vegetarians, or 80 vegans. Sociodemographic information, racing experience, and patterns of supplement intake, including type, frequency, dosage, etc., were collected using a questionnaire. Macronutrient intake was assessed using a food frequency questionnaire. ANOVA and logistic regression were used for data analysis. The prevalence of supplement intake was 51% for total runners and 72% among vegan runners. Age, sex, and race distance had no significant effect on the type of supplement intake (p > 0.05). Compared to omnivores and vegetarians, vegan runners reported consuming more vitamin (but not carbohydrate/protein or mineral) supplements (p < 0.05). Vitamin B₁₂, magnesium, and multivitamin had the most prevalent use amongst micronutrient supplements. This study points to a central role for supplementary nutritional strategies in different groups of distance runners. The present findings may help future investigations by design to identify specific requirements of endurance runners when adhering to specific kinds of diet particularly plant-based diets.

Quality Control of Protein Supplements: A Review

The growing consumer awareness regarding health and fitness has been leading to a huge rise in the consumption of nutritional supplements and, consequently, to an increase in concerns about their quality. In this sense, one of the most consumed products is protein supplements and, despite being safer than other types of supplements, there are several studies showing incompatibilities between what is present on the labels and their actual content. Therefore, this review is focused on gathering information about the problems arising from poor manufacturing practices and inadequate quality control of sport protein supplements. These issues are mainly related to three aspects: reduction of the supplements’ nutritional value, the presence of pharmacological substances, and contamination with microorganisms or toxic metals. Regarding the first aspect, reports about the “classic” addition of nitrogen-rich compounds to mask the protein content measured by the Kjeldahl method were discussed, as well as recent topics such as the addition of cheaper proteins to produce an “undetectable” adulteration in whey protein supplements. With respect to the presence of pharmacological compounds, it is a finding that is not very common in protein supplements; however, even trace amounts of foreign substances in this type of product may cause adverse effects to consumers, and, in the case of an elite athlete, may result in doping. Finally, we discuss about the contamination with microorganisms and toxic metals, this latter being a subject that should be further explored due to few studies in the literature.

Attitudes Toward and Susceptibility to Doping in Spanish Elite and National-Standard Track and Field Athletes: An Examination of the Sport Drug Control Model

The Sport Drug Control Model (SDCM) is likely to be the model which most explicitly represents the theoretical paradigm of the psychological study of the use of doping in sport. This model can be further developed through its analysis in different populations and cultures. The main aim of this study was to empirically test the SDCM while analyzing for the first time the intentions and attitudes toward doping in Spanish track and field athletes. A secondary aim was to assess the extent to which the variables in the model together predict attitude, susceptibility, and behavior toward the use of performance-enhancing substances. Participants were 281 Spanish elite and national-standard track and field athletes from whom 80.1% were 18-28 years old and 49.5% were females. Participants completed the SDCM questionnaire measuring morality, legitimacy, benefits appraisal, threat appraisal, self-efficacy to refrain from doping, reference groups' endorsement of doping methods/substances, use of legal supplements, availability and affordability of doping, attitudes toward doping, susceptibility to doping and, self-reported use of banned performance-enhancing substances or methods. Structural equation modeling supported a good fitness of the SDCM and confirmed that positive attitudes toward doping predicted high susceptibility to doping (β = 0.55, p < 0.001), which is in turn associated with the use of prohibited substances and methods (β = 0.12, p < 0.05). The factors that have most influence on attitudes toward doping are morality (β = 0.46, p < 0.001) and reference group opinion (β =0.62, p <0.001). Self-reported doping use was 9.6%. These findings confirm SDCM reproducibility and variability (as it accounts for several variables) in Spanish track and field competitive athletes. It is recommended to implement preventive programs which allow athletes to acquire a strong moral stance against doping and coaches to employ the tools required to instill and educate their athletes in rejecting these illegal practices that corrupt the integrity of competitive sport.