Prevalence of Dietary Supplement Use by Athletes: Systematic Review and Meta-Analysis

Nutritional Ergogenic Aids in Racquet Sports: A Systematic Review

A nutritional ergogenic aid (NEA) can help athletes optimize performance, but an evidence-based analysis is required in order to support training outcomes or competition performance in specific events. Racquet sports players are regularly exposed to a high-intensity workload throughout the tournament season. The activity during a match is characterized by variable durations (2–4 h) of repeated high-intensity bouts interspersed with standardized rest periods. Medline/PubMed, Scopus, and EBSCO were searched from their inception until February 2020 for randomized controlled trials (RCTs). Two independent reviewers extracted data, after which they assessed the risk of bias and the quality of trials. Out of 439 articles found, 21 met the predefined criteria: tennis (15 trials), badminton (three trials), paddle (one trial), and squash (two trials). Among all the studied NEAs, acute dosages of caffeine (3–6 mg/kg) 30–60 min before a match have been proven to improve specific skills and accuracy but may not contribute to improve perceived exertion. Currently, creatine, sodium bicarbonate, sodium citrate, beetroot juice, citrulline, and glycerol need more studies to strengthen the evidence regarding improved performance in racquet sports.

Understanding Cannabis-Based Therapeutics in Sports Medicine

CONTEXT

With increased use of cannabis-based products by the public for both recreational and medical use, sports medicine clinicians should be informed of historical context, current legal considerations, and existing evidence with regard to efficacy, safety, and risks in the athletic community.

EVIDENCE ACQUISITION

A review of ClinicalTrials.gov, MEDLINE, and CINAHL from 2015 to present was conducted with emphasis on the most recent literature using search terms, cannabis, nabiximols, cannabinoids, pain management, THC, CBD, and marijuana. Bibliographies based on original search were utilized to pursue further literature search.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 3.

RESULTS

At present, limited high-quality studies exist for use of cannabinoids for acute pain, chronic pain, or concussion. None of the trials involving cannabinoids included the athletic population. Thus, results from this clinical review are extrapolated to conditions of the sports medicine population. For acute pain, 2 small-randomized double-blinded crossover trials concluded no immediate effect of cannabinoid therapy. More robust evidence exists for treatment of chronic pain conditions through meta-analysis and systemic reviews. Cannabinoid therapy exhibits moderate efficacy as a treatment for some chronic pain conditions. Investigations included a broad spectrum of chronic pain conditions, including neuropathic, musculoskeletal, inflammatory, and central pain conditions, and reveal reduction in pain and improvement of quality of life with limited adverse effects. For concussion, evidence is based on preclinical in vitro and animal models revealing possible neuroprotective effects as well as 2 clinical studies involving the presence of cannabinoids for concussion (some sports-related), but there are no high-quality trials evaluating efficacy for treatment with cannabinoids at this time.

CONCLUSION

Although various biochemical explanations exist on the use of cannabinoid therapy through modulation of the endocannabinoid system for several medical issues affecting athletes, recommendations from clinicians must be extrapolated from a majority of research done in the nonathletic population. Lack of strong-quality clinical evidence, coupled with inconsistent federal and state law as well as purity issues with cannabis-based products, make it difficult for the sports medicine clinician to widely recommend cannabinoid therapeutics at present. Future larger, higher quality clinical research studies with standardized pure extracts will better guide appropriate medical use going forward. At present, evidence for a multitude of therapeutic applications is emerging for cannabinoid treatment approaches. With emphasis placed on patient-centered clinical decisions, cannabinoids hold promise of treatment for athletes with chronic pain conditions. Clinicians who treat the athletic community must consider legal and ethical issues when discussing and recommending the use of cannabinoids, with acknowledgment of inconsistencies in purity of various formulations and concerns of drug testing.

Third-Party Testing Nutritional Supplement Knowledge, Attitudes, and Use Among an NCAA I Collegiate Student-Athlete Population

Dietary supplements, sports foods, and ergogenic supplements are consumed to increase performance, recovery, and health, but risk contamination with illegal substances. Third-party testing programs may assist in regulating the purity and safety of supplements, yet athletes' attitudes and use of such programs are not widely reported. This study examined nutritional supplement knowledge, attitudes, and use, as well as the purchase of third-party tested supplements among university student-athletes (N = 138). Knowledge of nutritional supplements yielded a median and (IQR) score of 25% (17 to 42%). Sixteen percent of student-athletes said they were knowledgeable about supplements and their effects, p < 0.001. All athletes stated they used a dietary supplement or sports food at least once within the last 12 months, and 77% consumed at least one “claimed to be” ergogenic supplement. Sixty-six percent of student-athletes purchased nutritional supplements not provided by the athletic department. Females athletes were more likely to consume a combination of vitamins and single minerals, a larger variety of sports foods, exotic berries, herbs, maca root powder, ribose, ephedra, colostrum, and hydroxy-methyl-buterate (HMB) than males. Over 90% believed it was essential to know if a supplement was third-party tested. However, only 57% stated the supplements bought were third-party tested. No sex differences were found for nutritional supplement knowledge, attitudes, and use of third-party testing programs. Our results indicate a need to improve student-athletes' attitudes toward and knowledge of nutritional supplements, and the initiation of programs to assist in the choosing and consuming of third-party tested supplements.

Pre-Exercise Nutrition Habits and Beliefs of Endurance Athletes Vary by Sex, Competitive Level, and Diet

OBJECTIVE

The purpose of this study was to determine the self-reported beliefs and practices relating to pre-exercise nutrition intake among endurance athletes of varying ages and competitive levels and examine differences based on sex, competitive level, and habitual dietary pattern.

METHOD

An anonymous online survey was circulated internationally in English and completed by 1950 athletes of varying competitive levels (51.0% female, mean age 40.9 years [range 18:78]). Survey questions included training background, determinants of pre-exercise nutrition intake and composition, and timing relative to exercise.

RESULTS

Prior to morning exercise, 36.4%, 36.0%, and 27.6% of athletes consumed carbohydrate-containing food/drinks before almost every workout, some of the time, and never/rarely, respectively, with significant effects of sex (p < 0.001, Cramer's V (ϕ_c) = 0.15) and competitive level (p < 0.001, ϕ_c = 0.09). Nutritional intake before exercise varied based on workout duration for 47.6% of athletes, with significant effects of sex (ϕ_c = 0.15) and habitual diet (ϕ_c = 0.19), and based on workout intensity for 39.1% of athletes, with significant effects of sex (ϕ_c = 0.13) and habitual diet (ϕ_c = 0.17, all p < 0.001). Additionally, 89.0% of athletes reported using at least some type of dietary supplement (including caffeine from coffee/tea) within 1 hour before exercise.

CONCLUSIONS

Overall, nearly all factors measured relating to pre-exercise nutrition intake varied by sex, competitive level, habitual dietary pattern, and/or intensity/duration of the training session and suggest a large number of athletes may not be following current recommendations for optimizing endurance training adaptations.

Prioritized Dietary Supplement Information Needs of 307 NCAA Division I Student Athletes

OBJECTIVE

To evaluate dietary supplement information needs among collegiate athletes.

METHODS

Three hundred seven (n = 154 male; n = 153 female) student athletes participating in a National Collegiate Athletic Association Division I team completed a dietary supplement survey. Qualitative coding addressed open-ended responses, and chi-square test of independence explored differences among athlete subgroups.

RESULTS

Five themes representing athletes' information needs included quality/composition (53.5%; n = 77), general information (31.9%; n = 46), nutrition information (30.6%; n = 44), performance (18.8%; n = 27), and body composition (13.2%; n = 19). Athletes with "no" or "minimal" (n = 63), vs "moderate" or "strong" (n = 195), perceived knowledge of supplement safety were more likely to list a question about supplement quality or composition (34.9% [n = 22/63] vs 21.5% [n= 42/195]; P = .03; chi-square = 4.6).

CONCLUSIONS AND IMPLICATIONS

Further research is needed to corroborate findings to inform educational efforts and promote safe and effective use of dietary supplements by student athletes.

Dietary Intake, Body Composition and Iron Status in Experienced and Elite Climbers

Climbing has developed into a popular recreational and elite sport, evidenced by a growing number of licenced competition athletes, and the acceptance into the Olympic calendar for Tokyo 2020. A nutritional assessment, including the evaluation of anthropometric and biochemical data, has not been previously reported in climbing athletes. Therefore, the aim of this study was to assess the dietary intake, body composition, and iron status in experienced climbers, across a range of performance levels. Forty climbers (n = 20 male, n = 20 female; 8.8 ± 6.6 years' experience; BMI 21.6 ± 1.7) aged 18–46 (30.3 ± 6.7 years) participated in the study. Dietary intake was recorded in a 3-days diet diary. Body composition was assessed using a skinfold profile and iron status via blood markers. Mean energy intake was 2154.6 ± 450 kcal·day⁻¹, with 30% of male climbers and 5% of female climbers failing to meet predicted resting metabolic rate. Furthermore, 77.5% of participants failed to meet a predicted energy requirement to support a “moderate” training programme. There were no significant correlations between daily energy intake and exercise volume. Mean intake of carbohydrate, protein and fat was 3.7 ± 0.9 g·kg⁻¹·day⁻¹, 1.6 ± 0.5 g·kg⁻¹·day⁻¹, and 1.4 ± 0.4 g·kg⁻¹·day⁻¹, respectively, with no significant difference between genders. Approximately 17% of males (n =3) and 45% of females (n = 9) had a sub-optimal iron status. Thirty percent of females met the classification criteria for iron deficiency. Mean serum ferritin was significantly greater in males, compared to females (102.7 ± 54.9 vs. 51.4 ± 24.2 μg·L⁻¹; p ≤ 0.01) and significantly lower in vegan/vegetarians vs. omnivores, in female climbers only (33.2 ± 14.8 vs. 57.5 ± 24 μg·L⁻¹; p = 0.05). No significant differences were observed between climbing ability groups (intermediate-advanced/elite-higher elite) for body composition, dietary intake, or iron status, for males or females. These findings suggest that experienced climbers are at risk of energy restriction and iron deficiency, therefore, routine assessment of nutritional status is warranted. Future research should consider iron status in relation to energy availability and investigate additional factors which may predispose this population to iron deficiency, as well as the risk of relative energy deficiency in sport (RED-S).

High Prevalence of Supplement Intake with a Concomitant Low Information Quality among Swiss Fitness Center Users

BACKGROUND

The aim of this study was to screen the prevalence of supplement use in Swiss fitness center users and what information sources they consulted.

METHODS

Customers of 10 fitness centers were screened with a quantitative questionnaire.

RESULTS

Eighty two percent of the 417 fitness center users consumed at least one supplement per week. Supplement intake correlated with training frequency (rs = 0.253, p < 0.001). The most prevalent products were protein supplements (used by 49% of the study population), magnesium (34%), and multi-micronutrient supplements (31%). The average number of supplement servings per week among consumers was 17.1 (SD: 16.1, median: 11.0) and the average number of different products used was 6.9 (SD: 4.4, median: 6.0). The most frequently used information sources were the coach/trainer (28%), the website of the supplement seller (26%), and training peers (24%). Thirty seven percent were informed or informed themselves about potential risks associated with the supplement used. The leading reasons for selecting the information source were the desire for scientific-based information followed by the education level of the informing person.

CONCLUSIONS

A high prevalence of supplement intake among Swiss fitness center users was associated with a low level of information quality and a low prevalence of risk information. A discrepancy between a desire for high quality evidence-based information and a contrasting behavior was detected.

Healthy lifestyles among military active duty service members, and associations with body-building and weight-loss supplement use

PURPOSE

The purpose of this study was to characterize health behavior profiles among active duty service members and associate these profiles with body-building and weight-loss dietary supplement (DS) use.

METHODS

Based on U.S. active duty service members who completed the 2011 Health-Related Behavior Survey (n = 39,877), we used latent class analysis to place respondents into latent classes (using healthy/unhealthy food consumption, aerobic activity, strength training, and sleep) and examined associations between latent class and DS use.

RESULTS

We identified seven health behavior classes that could be classified by physical activity and diet. Three classes with high activity were further characterized by healthy diet (24%); few unhealthy foods (18%); and unrestricted diet (9%). Three classes with low activity were further characterized by restricted diet (15%), healthy diet (15%), and unhealthy diet (6%). The last class (13%) reported moderate levels of all behaviors. The classes did not vary by sleep. Participant characteristics across most classes were relatively homogenous along demographics and military branch. The active classes had relatively higher usage of body-building and weight-loss DSs.

CONCLUSIONS

Latent classes from health behavior indicators might be considered "market segments", which can be targeted with distinct messaging. Service members appear to consume DSs as part of an otherwise healthy lifestyle.

Effects of Dietary Supplements on Adaptations to Endurance Training

Endurance training leads to a variety of adaptations at the cellular and systemic levels that serve to minimise disruptions in whole-body homeostasis caused by exercise. These adaptations are differentially affected by training volume, training intensity, and training status, as well as by nutritional choices that can enhance or impair the response to training. A variety of supplements have been studied in the context of acute performance enhancement, but the effects of continued supplementation concurrent to endurance training programs are less well characterised. For example, supplements such as sodium bicarbonate and beta-alanine can improve endurance performance and possibly training adaptations during endurance training by affecting buffering capacity and/or allowing an increased training intensity, while antioxidants such as vitamin C and vitamin E may impair training adaptations by blunting cellular signalling but appear to have little effect on performance outcomes. Additionally, limited data suggest the potential for dietary nitrate (in the form of beetroot juice), creatine, and possibly caffeine, to further enhance endurance training adaptation. Therefore, the objective of this review is to examine the impact of dietary supplements on metabolic and physiological adaptations to endurance training.

Protein Supplementation in Sport: Source, Timing, and Intended Benefits

PURPOSE OF REVIEW

The purpose of this review is to provide background on the present literature regarding the utility and effectiveness of protein supplements, including protein source and nutrient timing.

RECENT FINDINGS

In the setting of adequate dietary protein consumption, research suggests some benefit particularly in sport or exercise activities. Protein supplements command a multi-billion-dollar market with prevalent use in sports. Many individuals, including athletes, do not consume optimal dietary protein on a daily basis. High-protein diets are remarkably safe in healthy subjects, especially in the short term. Some objective outcomes are physiologic and may not translate to clinically relevant outcomes. Athletes should, however, consider long-term implications when consuming high quantities of protein in dietary or supplement form.

Use of nutritional supplements by elite Japanese track and field athletes

BACKGROUND

While scientific evidence supports the efficacy of only limited nutritional supplements (NS) on sports performance, the use of NS is widespread in athletes. Given the serious issues of health damage or unintended Anti-Doping Rule Violations due to ingestion of contaminated NS in sports, accurately understanding NS practices by athletes is crucial. This study therefore elucidated the use of NS by elite Japanese track and field (TF) athletes.

METHODS

The subjects were 574 Japanese TF athletes, including 275 junior athletes (under 20 years) and 299 senior athletes, who participated in international competitions from 2013 to 2018. Data on NS use were collected through pre-participation medical forms obtained from all entrants before their participation in competitions. NS users were requested to report the product names and primary components of all NS they were taking.

RESULTS

The overall prevalence of NS use was 63.9%. The mean number of NS products used per athlete was 1.4. The prevalence was significantly higher in women (69.2%) than in men (59.6%) (p = 0.018) and significantly higher in senior athletes (68.9%) than in junior athletes (58.9%) (p = 0.012). The prevalence of NS use was higher in long-distance runners (75.8%) and lower in jumpers (52.3%) and throwers (49.2%) than other disciplines (p < 0.001). The most prevalent components were amino acids (49.3%), followed by vitamins (48.3%), minerals (22.8%), and protein (17.8%).

CONCLUSIONS

Approximately two-thirds of elite Japanese TF athletes reported the use of NS, and NS practices varied by gender, age, and discipline.

Acute Consumption of Varied Doses of Cocoa Flavanols Does Not Influence Exercise-Induced Muscle Damage

Polyphenol consumption has become a popular method of trying to temper muscle damage. Cocoa flavanols (CF) have attracted attention due to their high polyphenol content and palatability. As such, this study will investigate whether an acute dose of CF can aid recovery following exercise-induced muscle damage. The study was a laboratory-based, randomized, single-blind, nutrient-controlled trial involving 23 participants (13 females and 10 males). Participants were randomized into either control ∼0 mg CF (n = 8, four females); high dose of 830 mg CF (CF830, n = 8, five females); or supra dose of 1,245 mg CF (CF1245, n = 7, four females). The exercise-induced muscle damage protocol consisted of five sets of 10 maximal concentric/eccentric hamstring curls and immediately consumed their assigned drink following completion. To measure muscle recovery, maximal voluntary isometric contraction (MVIC) of the knee flexors at 60° and 30°, a visual analog scale (VAS), and lower-extremity function scale were taken at baseline, immediately, 24-, 48-, and 72-hr postexercise-induced muscle damage. There was a main effect for time for all variables (p < .05). However, no significant differences were observed between groups for all measures (p ≥ .17). At 48 hr, there were large effect sizes between control and CF1245 for MVIC60 (p = .17, d = 0.8); MVIC30 (p = .26, d = 0.8); MVIC30 percentage change (p = .24 d = 0.9); and visual analog scale (p = .25, d = 0.9). As no significant differences were observed following the consumption of CF, there is reason to believe that CF offer no benefit for muscle recovery when ingested acutely.

Analysis of Sports Supplements Consumption in Young Spanish Elite Dinghy Sailors

The sports performance of dinghy sailors is determined by their state of nutrition and hydration. Sports supplementation plays a prominent role in elite sailors, being essential in periods of competition due to its characteristics. This study aims to analyze the consumption of sports supplements (SS) in the different categories and groups of sailors based on the level of evidence, differentiating according to sex, competitive level, and type of boat. A total of 42 sailors from national and international levels and belonging to the Laser, 420, Techno-293 and RS:X classes participated in this study. They completed a questionnaire with questions about the consumption of SS and the possible repercussions on health and/or sports performance. The results were analyzed based on the different categorizations and group organization recently established by the Australian Institute of Sport (AIS), as well as by sex, level of competition and class to which the participants belonged. The male sailors and those who competed internationally had a higher prevalence in the consumption of SS. Among the classes of vessels studied, class 420 had the lowest SS consumption. SS intake was higher during competition days, regardless of sex or level of competition. Based on the classification established by the AIS, statistically significant differences were observed in sex, level of competition, and the type of boat.

A Randomised, Placebo-Controlled, Crossover Study Investigating the Optimal Timing of a Caffeine-Containing Supplement for Exercise Performance

BACKGROUND

Pre-exercise supplements containing low doses of caffeine improve endurance exercise performance, but the most efficacious time for consumption before intense endurance exercise remains unclear, as does the contribution of caffeine metabolism.

METHODS

This study assessed the timing of a commercially available supplement containing 200 mg of caffeine, 1600 mg of β-alanine and 1000 mg of quercetin [Beachbody Performance Energize, Beachbody LLC, USA] on exercise performance, perception of effort and plasma caffeine metabolites. Thirteen cyclists (V̇O_2max 64.5 ± 1.4 ml kg^- 1 min^- 1 (± SEM)) completed four experimental visits consisting of 30 min of steady-state exercise on a cycle ergometer at 83 ± 1% V̇O_2max followed by a 15-min time trial, with perceived exertion measured regularly. On three of the visits, participants consumed caffeine either 35 min before steady-state exercise (PRE), at the onset of steady-state (ONS) or immediately before the time trial (DUR) phases, with a placebo consumed at the other two time points (i.e. three drinks per visit). The other visit (PLA) consisted of consuming the placebo supplement at all three time points. The placebo was taste-, colour- and calorie-matched.

RESULTS

Total work performed during the time trial in PRE was 5% greater than PLA (3.53 ± 0.14 vs. 3.36 ± 0.13 kJ kg^- 1 body mass; P = 0.0025), but not ONS (3.44 ± 0.13 kJ kg^- 1; P = 0.3619) or DUR (3.39 ± 0.13 kJ kg^- 1; P = 0.925), which were similar to PLA. Perceived exertion was lowest during steady-state exercise in the PRE condition (P < 0.05), which coincided with elevated plasma paraxanthine in PRE only (P < 0.05).

CONCLUSION

In summary, ingestion of a pre-exercise supplement containing 200 mg caffeine 35 min before exercise appeared optimal for improved performance in a subsequent fatiguing time trial, possibly by reducing the perception of effort. Whether this was due to increased circulating paraxanthine requires further investigation.

TRIAL REGISTRATION

ClinicalTrials.Gov, NCT02985606 ; 10/26/2016.

The Implementation and Evaluation of a Media Literacy Intervention About PAES Use in Sport Science Students

With respect to both competitive and amateur/fitness sports, media may strongly influence young people's opinions and behaviors concerning the use of PAES (Performance and Appearance Enhancing Substances). The present investigation addressed this topic by focusing on sport sciences students' beliefs concerning the possible role of media related to the implementation and evaluation of a PAES-focus media literacy intervention conducted with sport science students. This study relied on a sample of 521 students (attrition rate 10.3%) (45.1% female, mean age = 22.6, SD = 2.20), which provided baseline data on students' levels of media literacy concerning the use of PAES (i.e. "descriptive sample"), and a sample of 248 students, who participated in and provided data on the media literacy intervention. This latter sample included a group of 128 students (44.5% female, mean age = 23.03, SD = 3.76) who actively participated in the intervention (i.e. "intervention group"), and a group of 120 students who did not (i.e. "control group", 53.3% female, mean age = 22.25, SD = 2.47). All students filled out media literacy questionnaires targeting students' awareness of media influence, their views about the realism of media content, their sense of confidence in dealing with media messages, and their positive attitudes toward PAES use. Analyses of questionnaire data showed that students are relatively aware of media influence on people's views and behaviors with respect to PAES use. At the same time, students also believed that young people do not consider media as "realistic sources" of information; nonetheless, they also did not consider themselves entirely capable of dealing effectively with media messages. With respect to the intervention, students overall appreciated and greatly welcomed the educational program on media literacy, and the analyses of intervention data across intervention and control groups showed that key media literacy variables changed over time, attesting to the overall effectiveness of the intervention.

Prevalence of dietary supplement use by gym members in Portugal and associated factors

Background

Although there seems to be an increasing interest in the use of dietary supplements in those who exercise recreationally and want to improve body composition, there is little published data regarding gym users and dietary supplement use.

Methods

This cross-sectional study describes the prevalence and type of supplements used by gyms members, the reasons for using them and the information source using a self-administered online questionnaire.

Results

Of the 459 participants (301 females) who answered the survey, 43.8% reported using dietary supplements. Users were more likely men (62.7% vs. 33.9%, p < 0.05), younger (32 ± 9 vs. 34 ± 11 years, p < 0.05) and trained more hours per week (6 ± 3 vs 4 ± 3 h, p < 0.05) than non-users. The most consumed supplements were proteins (80.1%), multivitamins and/or minerals (38.3%), sport bars (37.3%), branched-chain amino acids (BCAA’s) (36.8%) and n-3 fatty acids (35.5%). Men consumed more arginine, BCAA’s, creatine, glutamine, β-hydroxy-β-methylbutyrate (HMB), proteins, β-alanine, taurine, multivitamin/minerals, and carbohydrate supplements (p < 0.05). The most commonly cited reasons for the use of supplements were gaining muscle (55.7%), accelerating recovery (52.7%) and improving performance (47.3%). Men have more often referred increase strength, increase resistance, gain muscle mass, accelerate recovery and improve performance as reasons to use supplements than women (p < 0.05). Those who mentioned muscle gain as a reason were younger than those who did not (30.4 years vs. 33.7 years, p < 0.05). The sources of information most mentioned were registered dietitians (23.1%), internet (22.2%) and him/herself (16.6%). The majority (> 70%) of participants declared being well or very well informed about supplements, while only a minority (4%) felt very poorly or poorly informed. Most individuals purchased dietary supplements from the internet (56.2%) and supplement/health food stores (43.4%).

Conclusion

This study concluded that gyms users are large consumers of dietary supplements, and are more likely to be men, young, use protein powders, aiming to increase muscle mass, obtain information from registered dietitians, consider themselves well informed and buy supplements online.

The gender dependent influence of sodium bicarbonate supplementation on anaerobic power and specific performance in female and male wrestlers

The aim of this study was the assessment of progressive low-dose sodium bicarbonate (NaHCO₃) supplementation on the anaerobic indices in two bouts of Wingate tests (WT) separated by wrestling-specific performance test and assessing the gender differences in response. Fifty-one (18 F) wrestlers completed a randomized trial of either a NaHCO₃ (up to 100 mg·kg⁻¹) or a placebo for 10 days. Before and after treatment, athletes completed an exercise protocol that comprised, in sequence, the first WT₁, dummy throw test (DT), and second WT₂. The number of completed throws increased significantly in males from 19.3 ± 2.6 NaHCO_3pre to 21.7 ± 2.9 NaHCO_3post. ΔWT₂-WT₁ improved particularly in the midsection of 30-s WT on NaHCO₃. However, no significant differences were found in peak power (PP), power drop (PD) and average power (AP) (analyzed separately for each WT), and ΔWT₂-WT₁ in PP and PD. Interaction with gender was significant for AP, PP and PD, every second of WT₁ and WT₂, as well as DT test. In conclusion, our study suggests that the response to NaHCO₃ may be gender-specific and progressive low-dose NaHCO₃ supplementation allows the advantageous strengthening of wrestling-specific performance in males. It can also lead to maintenance of high anaerobic power mainly in the midsection of the 30-s Wingate test.

Supplements and Nutritional Interventions to Augment High-Intensity Interval Training Physiological and Performance Adaptations-A Narrative Review

High-intensity interval training (HIIT) involves short bursts of intense activity interspersed by periods of low-intensity exercise or rest. HIIT is a viable alternative to traditional continuous moderate-intensity endurance training to enhance maximal oxygen uptake and endurance performance. Combining nutritional strategies with HIIT may result in more favorable outcomes. The purpose of this narrative review is to highlight key dietary interventions that may augment adaptations to HIIT, including creatine monohydrate, caffeine, nitrate, sodium bicarbonate, beta-alanine, protein, and essential amino acids, as well as manipulating carbohydrate availability. Nutrient timing and potential sex differences are also discussed. Overall, sodium bicarbonate and nitrates show promise for enhancing HIIT adaptations and performance. Beta-alanine has the potential to increase training volume and intensity and improve HIIT adaptations. Caffeine and creatine have potential benefits, however, longer-term studies are lacking. Presently, there is a lack of evidence supporting high protein diets to augment HIIT. Low carbohydrate training enhances the upregulation of mitochondrial enzymes, however, there does not seem to be a performance advantage, and a periodized approach may be warranted. Lastly, potential sex differences suggest the need for future research to examine sex-specific nutritional strategies in response to HIIT.

An Investigation of Habitual Dietary Supplement Use Among 557 NCAA Division I Athletes

Background: Supplements may expose athletes to dangerous ingredients, banned substances, toxins or contaminants; however, few investigations assess use among collegiate athletes in the U.S.Objective: This cross-sectional study evaluated habitual dietary supplement intake, defined use ≥2 days/week over the past year, in NCAA Division I athletes.Methods: Male and female members of a NCAA Division I team, at two universities in southern California completed a 13-item survey. Among 705 eligible participants, 596 submitted surveys (84.5% response rate), 557 surveys included complete data. Chi-square (χ²) analyses evaluated differences among athletes based on sex, weight status, year in college, and sport-type. Independent t-test or ANOVA evaluated mean differences for continuous variables.Results: A total of 45.2% athletes (n = 252) reported taking supplements (≥2 days/week over the past year). Vitamin/minerals (25.5%, n = 142), protein/amino acids (24.6%, n = 137) were used most frequently. Male, vs female athletes, took more supplements overall (1.2 ± 0.1 vs 0.8 ± 0.1, p = 0.004) and indicated higher use of protein/amino acid products (34.2% vs 13.5%, p < 0.005), whereas, females reported higher use of vitamin/minerals (30.5% vs 21.1%, p < 0.05). Higher supplement use was also reported by athletes with BMI ≥ 30.0 kg/m² (vs <30 kg/m², 1.9 ± 0.3 vs 1.0 ± 0.1, p = 0.02), and athletes in ≥ third college year (vs first or second year, 1.2 ± 0.1 vs 0.9 ± 0.1, p = 0.03).Conclusions: Nearly half of NCAA athletes reported habitual supplements use, with significant variation in patterns based on sex, sport-type, year in college, and weight status.

Glutamine powder-induced hepatotoxicity: it is time to understand the side effects of sports nutritional supplements

Glutamine has been considered as a dietary supplement with a non-essential amino acid structure. Some studies have found that liver failure may be associated with a high plasma glutamine level. Consumption of this product may be linked to potential adverse effects. This report describes the first case of glutamine-induced hepatotoxicity. A 35-year-old female athlete with severe abdominal pain and scleral icterus was referred to the hospital. She had been taking glutamine powder for the past three weeks. Impaired liver function test and imaging evaluation suggested hepatotoxicity. Glutamine consumption was discontinued and the patient was closely monitored. Finally, after two weeks, the patient recovered successfully. This novel case was the first report regarding glutamine-induced hepatotoxicity. Health care providers must know that consumption of dietary supplements such as glutamine may be associated with serious side effects. Liver damage is a possible side effect of glutamine. Hence it is necessary to consider hepatotoxicity as an adverse reaction in case of glutamine supplement consumption.

The effects of vitamin C and E on exercise-induced physiological adaptations: a systematic review and Meta-analysis of randomized controlled trials

We conducted a systematic review and meta-analysis of randomized controlled trials examining the effect of vitamin C and/or E on exercise-induced training adaptations. Medline, Embase and SPORTDiscus databases were searched for articles from inception until June 2019. Inclusion criteria was studies in adult humans where vitamin C and/or E had to be consumed alongside a supervised exercise training program of ≥4 weeks. Nine trials were included in the analysis of aerobic exercise adaptations and nine for resistance training (RT) adaptations. Vitamin C and/or E did not attenuate aerobic exercise induced improvements in maximal aerobic capacity (V ̇ O2max) (SMD -0.14, 95% CI: -0.43 to 0.15, P = 0.35) or endurance performance (SMD -0.01, 95% CI: -0.38 to 0.36, P = 0.97). There were also no effects of these supplements on lean mass and muscle strength following RT (SMD -0.07, 95% CI: -0.36 to 0.23, P = 0.67) and (SMD -0.15, 95% CI: -0.16 to 0.46, P = 0.35), respectively. There was also no influence of age on any of these outcomes (P > 0.05). These findings suggest that vitamin C and/or E does not inhibit exercise-induced changes in physiological function. Studies with larger sample sizes and adequate power are still required.

The effects of Jilin sika Deer's (Cervus dybowski) tendon liquid supplementation on endurance drop jumps performance, biochemistry profile of free boxing players

ETHNOPHARMACOLOGICAL RELEVANCE

Risk of anterior cruciate ligament is a persistent and severe problem in athletes owing to strenuous exercise-induced lower-body injury. Tendon of deer liquid (TD) a familiar traditional Chinese medicine, has been used for strengthening the bones and muscles.

AIM OF THE STUDY

In this study, we seek to demonstrate the application of TD in improving endurance exercise performance and reducing the risk of endurance training injury for free boxing players.

MATERIALS AND METHODS

Sixteen male free boxing players were randomly assigned to the TD and placebo groups. Body composition, clinical biochemistry profiles, kinematic and physiology exercise tests were evaluated at 2 time points - pre-supplementation (pre-) and after 6 weeks post-supplementation (post-).

RESULTS

TD group exhibited significant increase in levels of serum total protein (TP) compared to the placebo group after a 6-week supplementation. Following the treadmill test, serum glucose and maximal oxygen consumption (VO₂ max) levels were increased in the TD group. In the endurance test consisting of 200 counts of drop vertical jumps (DVJs), subjects in the TD group also showed an increase in vertical jump height and reduced risk of musculoskeletal system injuries.

CONCLUSIONS

TD supplementation leads to better physiological adaptation in free boxing players and has the potential for use as a nutrient supplement toward a variety of benefits for endurance athletes.

Effect of Bang® Pre-Workout Master Blaster® combined with four weeks of resistance training on lean body mass, maximal strength, mircoRNA expression, and serum IGF-1 in men: a randomized, double-blind, placebo-controlled trial

Background

The aim of the current study was to determine if 4 weeks of consumption of Bang® Pre-Workout Master Blaster® (BMB; Vital Pharmaceuticals Inc., Weston, FL) combined with resistance training resulted in greater increases in muscle mass and maximal strength compared with resistance training combined with placebo (PLA). Additionally, we aimed to determine if BMB ingestion combined with resistance training preferentially altered resting skeletal muscle expression of microRNAs (miRs) or resting serum insulin-like growth factor (IGF-1).

Methods

Sixteen recreationally-active men completed the study. The study employed a block-randomized, double-blind, placebo-controlled, parallel design. Participants completed two testing sessions separated by 4 weeks of resistance exercise combined with daily supplementation of BMB or PLA. At each testing session, hemodynamics, body composition, and muscle and blood samples were obtained followed by strength assessments of the lower- and upper-body via measurement of squat and bench press one-repetition maximum (1-RM), respectively. A separate general linear model was utilized for analysis of each variable to determine the effect of each supplement (between-factor) over time (within-factor) using an a priori probability level of ≤0.05.

Results

No significant effects were observed for dietary intake, hemodynamics, fat mass, body fat percentage, or serum IGF-1. A greater increase in total body mass (3.19 kg, 95% CI, 1.98 kg, 4.40 kg vs. 0.44 kg, 95% CI, − 0.50 kg, 1.39 kg) and lean body mass (3.15 kg, 95% CI, 1.80 kg, 4.49 kg vs. 0.89 kg, 95% CI, − 0.14 kg, 1.93 kg) was observed for the BMB group compared with PLA (p <  0.01). A significant increase over time was observed for miR-23a (p = 0.02) and miR-23b (p = 0.05) expression. A greater increase in squat 1-RM was observed for the BMB group (23.86 kg, 95% CI, 16.75 kg, 30.97 kg) compared with the PLA group (14.20 kg, 95% CI, 7.04 kg, 21.37 kg, p = 0.04).

Conclusions

BMB supplementation combined with resistance exercise training for 4 weeks resulted in superior adaptations in maximal strength and LBM compared with resistance training with a placebo. No adverse resting hemodynamic or clinical blood safety markers were observed as a result of BMB supplementation. The superior outcomes associated with BMB supplementation could not be explained by resting serum IGF-1 or the skeletal muscle miRs measured, although resting miR-23a and miR-23b expression both increased as a result of resistance training.

Frequency and Causes of Consuming Sports Supplements and Understanding their Side Effects Among Bodybuilders in Fitness Gyms of Kermanshah City

Background:

Nowadays, paying attention to sports nutrition, particularly focus on using supplements among athletes is increasing rapidly.

Objective:

This study has been carried out in order to investigate the frequency and causes of consuming supplements and understanding the side effects related to their consumption among bodybuilders in Kermanshah City.

Methods:

The samples of this cross-sectional study include teenagers and young adults who are the members of fitness gyms around Kermanshah City. 244 individuals were selected as samples using simple random sampling. In order to gather the required data, a four-sectioned questionnaire designed by the research team was used. The data analysis was done using chi-square, independent ttest, and Pearson's and Spearman's correlation coefficients by SPSS-20.

Results:

The majority of bodybuilders participating in the study (95.3%) have used supplements. The sources suggesting the consumption of supplements included other athletes, the coach, the media, nutrition specialists, and medical doctors, respectively. Generally, 37 types of sports supplements are used by the bodybuilders. Based on their rank, the supplements include vitamin C, Creatine, vitamin E, multivitamin, and iron. The most frequent reasons for consuming sports supplements included muscle building, increasing energy, and improving athletic performance. There is a significant difference between male and female athletes with regards to knowing the psychological and sexual side effects of consuming sports supplements (P<0.05). In general, the level of understanding and knowing the side effects of consuming sports supplements among athletes is not desirable.

Conclusion:

Since a significant percentage of athletes, particularly male athletes, have a history of consuming sports supplements, it is necessary that the people related to this issue including athletes, coaches, doctors, and nutrition specialists, get sufficient information about the ingredients, side effects, benefits, and applications of various nutritional supplements. Dysfunctional beliefs about the supplements consumption or non-consumption should be discussed.

Epidemiology of dietary supplement use in Serbia: Report from Novi Sad

OBJECTIVES

The primary objectives were to assess the prevalence of dietary supplement (DS) use and to identify specific demographic and lifestyle characteristics of DS users from Novi Sad, Serbia as well as the most commonly used DS and reasons for their use.

DESIGN

Observational, cross-sectional study.

SETTING AND INTERVENTIONS

Data on demographics, lifestyle and dietary supplement use of 435 adults from Novi Sad, Serbia were collected using an online questionnaire.

RESULTS

In total, 435 subjects completed the questionnaire (62.3% women). Prevalence of dietary supplement use in the sample was 42.8%. More women used DS than men (p = 0.002). Higher use of DS was reported among individuals 65+, while the young used DS less (p = 0.001), but the highest proportions of DS users was from the 45-54 age group. DS were used more among those with lower education levels (p < 0.001) and no income (p = 0.009). The highest percentages of DS users reported daily intakes of fruits and moderate physical activity, were non-smokers and social drinkers. Main reason for DS use was maintaining general health. The most commonly used DS were minerals and/or vitamins (68.8%).

CONCLUSIONS

We report a high prevalence of dietary supplement use in Novi Sad. DS use was associated with being a female, being older and having minimal/average income, the latter being opposite of the usual findings. Our results warrant a more detailed examination of the association between income, DS use and healthcare availability in developing countries such as Serbia.

Muscular Atrophy and Sarcopenia in the Elderly: Is There a Role for Creatine Supplementation?

Sarcopenia is characterized by a loss of muscle mass, quality, and function, and negatively impacts health, functionality, and quality of life for numerous populations, particularly older adults. Creatine is an endogenously produced metabolite, which has the theoretical potential to counteract many of the morphological and metabolic parameters underpinning sarcopenia. This can occur through a range of direct and indirect mechanisms, including temporal and spatial functions that accelerate ATP regeneration during times of high energy demand, direct anabolic and anti-catabolic functions, and enhanced muscle regenerating capacity through positively impacting muscle stem cell availability. Studies conducted in older adults show little benefit of creatine supplementation alone on muscle function or mass. In contrast, creatine supplementation as an adjunct to exercise training seems to augment the muscle adaptive response to the training stimulus, potentially through increasing capacity for higher intensity exercise, and/or by enhancing post-exercise recovery and adaptation. As such, creatine may be an effective dietary strategy to combat age-related muscle atrophy and sarcopenia when used to complement the benefits of exercise training.

Position of the Academy of Nutrition and Dietetics: Micronutrient Supplementation

It is the position of the Academy of Nutrition and Dietetics that micronutrient supplements are warranted when requirements are not being met through the diet alone. Those with increased requirements secondary to growth, chronic disease, medication use, malabsorption, pregnancy and lactation, and aging may be at particular risk for inadequate dietary intakes. However, the routine and indiscriminate use of micronutrient supplements for the prevention of chronic disease is not recommended, given the lack of available scientific evidence. A few specific age and disease states that may benefit from micronutrient supplementation are discussed. The most common dietary supplements used by both children and adults in the United States contain micronutrients. Consumers may not be well informed about the safety and use of these products, and some may have difficulty interpreting product labels. Thus, the expertise of registered dietitian nutritionists and nutrition and dietetic technicians, registered, is needed to guide the safe and appropriate selection and use of micronutrient supplements. To accomplish this, registered dietitian nutritionists and nutrition and dietetic technicians, registered, must keep up to date on efficacy, safety, and the regulatory issues influencing the use of these products. This position paper aims to increase awareness of current issues relevant to micronutrient supplementation and of the resources available to assist registered dietitian nutritionists and nutrition and dietetic technicians, registered, in evaluating their potential benefits and adverse outcomes.

Why Do Athletes Choose Dietary Supplements? Reliability and Validity of the Dietary Supplement Choice Questionnaire (DSCQ) among Japanese College Athletes

To assess the reliability and validity of the Dietary Supplement Choice Questionnaire (DSCQ) to capture dietary supplement choice motives among Japanese college athletes. The cross-sectional study was performed in 2014. This study recruited 1,451 college athletes from sports-oriented clubs at the University of Tsukuba, Japan. The participants completed the DSCQ, health literacy, and subjective economic status; part of the participants completed a test-retest (n=378). A sample of 975 participants (28.0% female) included in the analysis. The DSCQ was developed through factor analysis. Seven factors emerged, and were labelled "popularity," "functionality," "price," "taste," "convenience," "antidoping" and "familiarity." Mostly acceptable reliability was seen across seven DSCQ factors (the internal consistency, Cronbach's α=0.62-0.85; the test-retest reliability coefficients, r=0.62-0.82), whereas convergent validity for price and antidoping factors was provided by significant associations with economic status and literacy (p<0.01). Findings showed reasonable evidence of reliability and validity of the DSCQ and provided the opportunity to comprehensively assess dietary supplement choice motives among Japanese college athletes.

Supplement Use and Behaviors of Athletes Affiliated With an Australian State-Based Sports Institute

The authors aimed to update knowledge of the use of supplements among Australian athletes at a state-based sports institute. The authors conducted a cross-sectional survey using an online questionnaire to assess the influence of age, sports category, and scholarship category on supplement use. Of 94 completed questionnaires, 82 (87%) indicated supplements in the previous 12 months (mean = 4.9 ± 3.3). No significant difference in supplement usage rate was identified when considering age, scholarship category, or sport category. The most frequently used supplements were sports drinks (70%), caffeine (48%), protein powder (42%), and sports bars (42%). Recovery (63%), health maintenance (59%), and improved energy (50%) were the most frequently reported rationale to use supplements. Allied health professionals and credible online resources were the predominant sources of influence regarding use. However, athletes from lower scholarship categories were more likely to have social media, parents, and siblings influence usage, and age was inversely related to increased influence from parents, social media, physicians not associated with the institute, the Internet, and siblings. Older athletes and those on higher scholarships were more likely to source supplements from training facilities and sports nutrition staff outside of the institute or direct from a supplier, whereas those on lower scholarships tended to rely more on family and friends for their supplements. Findings from this study show a high prevalence of supplement use and are the first to show an influence of social media, particularly in younger athletes. Opportunities exist to optimize how athletes are informed regarding supplement use and organizational and supplement policy.

Prevalence and Predictors of Higher-Risk Supplement Use Among Collegiate Athletes

Sassone, J, Muster, M, and Barrack, MT. Prevalence and predictors of higher-risk supplement use among National Collegiate Athletic Association Division I athletes. J Strength Cond Res 33(2): 443-450, 2019-This study aimed to identify the prevalence and predictors associated with the use of higher-risk dietary supplements, defined as supplements containing herbal ingredients, caffeine, or those classified for weight loss, muscle-building, or as a preworkout supplement, among 557 National Collegiate Athletic Association Division I male and female collegiate athletes. Although 252 (45.2%) athletes reported the use of a dietary supplement on ≥2 days per week over the past year, 46 (8.3%) athletes met criteria for higher-risk supplement use. Twenty (3.6%) athletes reported the use of herbal, 1 (0.2%) caffeinated, 5 (0.9%) weight loss, 28 (5.0%) preworkout, and 1 (0.2%) muscle-building supplements. Body mass index status (BMI ≥30 kg·m), sport-type (sports using the phosphocreatine energy system), and college year (≥4th year) were associated with the use of preworkout, muscle-building, or herbal supplements. A multiple regression analysis identified predictors of higher-risk supplement use including the number of dietary supplements used in the past year (odds ratio [OR] = 2.1, 95% confidence interval [CI] = 1.7-2.7, p < 0.001), the reported motivation of taking dietary supplements to gain muscle and lose body fat (OR = 3.5, 95% CI = 1.1-11.7, p = 0.04), and the motivation to increase athletic endurance (OR = 3.5, 95% CI = 4.0, 95% CI = 1.6-9.9, p < 0.005). These factors may be considered as a part of a screening process to evaluate athletes with an increased risk of higher-risk supplement use and potential consequences to health or eligibility status.

Prevalence and patterns of dietary supplement use in elite Spanish athletes

BACKGROUND

Dietary supplementation is a common strategy to achieve a specific health status or performance benefit. Several investigations have focused on the prevalence of dietary supplement use by athletes. However, information on how athletes manage the use and purchase of dietary supplements is scarce.

METHODS

Five hundred and twenty-seven high-performance athletes (346 males and 181 females), participating in individual and team sports, completed a validated questionnaire about use and purchase patterns of dietary supplements. The dietary supplements were categorized according to the International Olympic Committee (IOC) consensus.

RESULTS

Sixty four percent of the athletes (n = 337) used dietary supplements (median = 3; range 1 to 12). Age, sex, type of sport, level of competition, and professionalism influenced the prevalence of dietary supplement use (all p < 0.05). The most prevalent dietary supplement consumed was proteins (41%; n = 137), followed by amino acids/BCAA-based supplements (37%; n = 124). Additionally, as per group of supplements according to IOC consensus, 18% of the supplements were rated as having a low level of scientific evidence (e.g., glutamine, HMB, L-carnitine, etc). Most athletes (45%, n = 152) purchased dietary supplements in a store and 24% (n = 81) obtained them from a sponsor. Most athletes also (42%, n = 141) reported a self-organization of supplementation and did not consult with any professional. Last, 81% (n = 273) of athletes consuming supplements did not know any platform to check supplement safety/quality. For those who do not use dietary supplements (36% of the total sample, n = 190), most reported that they do not consider supplements necessary (72%, n = 137).

CONCLUSION

Dietary supplementation appears to be widely used in sport with a considerable proportion of athletes consuming supplements with low level of scientific evidence. Additionally, athletes seem to rely on inadequate sources of information and may be largely unaware of sources to detect supplement contamination.

Protein supplement use and prevalence of microalbuminuria in gym members

BACKGROUND

Protein supplement use is common in bodybuilders because protein supplements are thought to increase muscle mass by preventing protein catabolism during exercise routines. Information on the consequences of protein supplement use is scarce and contradictory. Therefore, the identification of a kidney damage marker, such as microalbuminuria, could be transcendent in preventing probable organ compromise in healthy persons. The aim of this study is to determine the presence of microalbuminuria in gym members and whether there is an associated risk with protein supplement use.

METHODS

An analytic, descriptive, cross-sectional study was conducted. It included gym members whose clinical and nutritional histories were taken, identifying protein supplement use. Microalbuminuria was then determined through a random urine sample. Descriptive and inferential statistics were used for the data analysis. The objective was to determine the presence of microalbuminuria in gym members and whether there is an associated risk with protein supplement use.

RESULTS

A total of 107 gym members, 71 men and 36 women, that met the inclusion criteria of the study were analyzed. Their mean age was 35±13 years, and the prevalence of microalbuminuria was 9.34%. There was active protein supplement use in 58% of the study participants, with a mean consumption duration of 16±22 months. No association with the presence of microalbuminuria was found (P=0.35).

CONCLUSIONS

The prevalence of microalbuminuria in gym members was higher than that of the general healthy population and was not associated with protein supplement use.

What drives athletes toward dietary supplement use: objective knowledge or self-perceived competence? Cross-sectional analysis of professional team-sport players from Southeastern Europe during the competitive season

BACKGROUND

Issues related to knowledge of nutrition and dietary supplementation (DS) are understudied in professional athletes. This study aimed to examine the possible association between knowledge of nutrition and DS (KN&DS) and dietary supplement use (DSU) among professional athletes involved in team sports.

METHODS

The sample comprised professional team-sport athletes (N = 912, age: 22.11 ± 3.37 years, 356 females) involved in four Olympic sports: basketball (N = 228), soccer (N = 324), volleyball (N = 154), and handball (N = 206). The participants were tested by previously validated questionnaires to examine their self-perceived competence on nutrition and DS (S/KN&DS), their objectively evaluated (tested) KN&DS (O/KN&DS), sociodemographic and sport-specific variables (predictors), and DSU (criterion). Associations between the predictors and the criterion (No-DSU - Irregular-DSU - Regular-DSU) were determined by multinomial regression analysis for the total sample and separately for the studied sports.

RESULTS

DSU was found to be less prevalent in older and more successful players. The O/KN&DS and S/KN&DS were positively correlated with DSU, but S/KN&DS was a stronger predictor of DSU than O/KN&DS. Sport-specific associations between predictors and criterion were identified, with stronger correlations in sports with a higher prevalence of DSU.

CONCLUSIONS

Due to the low correlations between O/KN&DS and S/KN&DS in the studied players, this study highlights the necessity for more frequent monitoring of biomarkers of nutritional status and its usage by coaches and practitioners to provide quantitative instruction.

Common Habits, Adverse Events, and Opinions Regarding Pre-Workout Supplement Use Among Regular Consumers

The purpose of the present study was to examine characteristics of multi-ingredient pre-workout supplement (MIPS) users, their common patterns/habits of MIPS ingestion, and their associated feelings about the effectiveness and safety of this class of supplements. An online electronic survey was distributed through social media to assess self-reported supplementation practices and preferences among adult males and females who reported regular MIPS use. A total of 1045 individuals responded, with 872 of these individuals (males: n = 636, 72.9%; females: n = 233, 26.7%; mean ± SD; age = 27.7 ± 7.9 years; training age = 8.2 ± 7.3 years) completing the survey. The majority of respondents reported the length of current or past MIPS consumption as greater than one year (n = 630, 72.2%), with ingestion frequencies primarily of four (n = 210, 24.1%) or five (n = 212, 24.3%) days per week of training. In addition, the three most popular goals for ingesting MIPS were increased energy and focus (n = 776, 89.0%), muscular endurance (n = 325, 37.3%), and blood flow or “pump” (n = 322, 37.0%). Although most users reported ingesting one serving size with each use, 14% reported ingesting two or more, and 18% indicated they ingest MIPS more than once per day. Importantly, over half (54%) of the respondents reported experiencing side-effects following MIPS use, including skin reactions, heart abnormalities, and nausea. Females were more likely than males to experience these side effects, despite being less likely to consume two or more serving sizes per dose. Our findings also indicated that MIPS users should consume no more than the recommended serving size of a given supplement, as the potentially significant variability in the caffeine content of MIPS products is compounded as more doses are consumed. Furthermore, MIPS users should minimize the ingestion of other supplements which contain high levels of niacin and caffeine, as the concurrent consumption of such products may put users above the tolerable upper limits for these substances.

Protein supplement consumption is linked to time spent exercising and high-protein content foods: A multicentric observational study

The main aim of this study is to analyze if protein supplement consumption and food patterns vary across three geographical regions and secondly to identify possible factors that increase the likelihood of ingesting protein supplements. A total of 916 responses from gym users of 3 countries (Italy, Turkey and UK) were entered for analysis. Questions were related to supplement consumption (protein and other supplements), food intake and training habits. A descriptive analysis, analysis of variance (ANOVA), and logistic regression were performed. No differences were found across groups regarding: prevalence of protein supplement consumption, typology of other ingested supplement and food intake. No relation was found between level of education (r = .12) or geographical region (r = .16) and protein consumption. The analysis showed that the coach is the main source of suggestion for the intake of protein supplements (52.3%). The logistic regression model highlighted that gym users who exercised more (OR 1.51, p < 0.001) and consumed higher quantities of chicken (OR 1.39, p < 0.001) eggs (OR 1.18, p < 0.001) and canned tuna (OR 1.15, p < 0.05) were more likely to use protein supplements. Geographical area does not seem to influence the supplementation pattern. Time spent exercising and high protein foods are factors associated with protein supplement consumption.

Evaluation and Behavior of Spanish Bodybuilders: Doping and Sports Supplements

The use of doping agents has these days become a public health problem, as it also affects young and non-competitive amateurs in different sports. To prepare for competition, bodybuilders perform aggressive dietary protocols, so, bodybuilders frequently consume nutritional supplements (NS) and banned substances in large dosages. Thus, the aim of this study is to analyze the prevalence of banned substances consumption and NS intake in competitive level bodybuilders. A total of 48 bodybuilders (44 males and 4 females) completed a validated online questionnaire on NS consumption. The quantitative data was presented as a mean (M) ± standard deviation (SD), as well as having minimum and maximum values. The categorical variables were expressed using frequencies and percentages. 83.3% of the participants declared that they had consumed or would consume banned substances, the most consumed being anabolic steroids (72.9%). One hundred percent of those sampled use NS. Whey protein (96%), branched-chain amino acids (BCAA) (94%), creatine (85%) and vitamin complexes (83%) were the most consumed, however, there is a low consumption of certain NS which could also increase athletic performance.

The Role of Mineral and Trace Element Supplementation in Exercise and Athletic Performance: A Systematic Review

Minerals and trace elements (MTEs) are micronutrients involved in hundreds of biological processes. Deficiency in MTEs can negatively affect athletic performance. Approximately 50% of athletes have reported consuming some form of micronutrient supplement; however, there is limited data confirming their efficacy for improving performance. The aim of this study was to systematically review the role of MTEs in exercise and athletic performance. Six electronic databases and grey literature sources (MEDLINE; EMBASE; CINAHL and SportDISCUS; Web of Science and clinicaltrials.gov) were searched, in accordance with PRISMA guidelines. Results: 17,433 articles were identified and 130 experiments from 128 studies were included. Retrieved articles included Iron (n = 29), Calcium (n = 11), Magnesium, (n = 22), Phosphate (n = 17), Zinc (n = 9), Sodium (n = 15), Boron (n = 4), Selenium (n = 5), Chromium (n = 12) and multi-mineral articles (n = 5). No relevant articles were identified for Copper, Manganese, Iodine, Nickel, Fluoride or Cobalt. Only Iron and Magnesium included articles of sufficient quality to be assigned as 'strong'. Currently, there is little evidence to support the use of MTE supplementation to improve physiological markers of athletic performance, with the possible exception of Iron (in particular, biological situations) and Magnesium as these currently have the strongest quality evidence. Regardless, some MTEs may possess the potential to improve athletic performance, but more high quality research is required before support for these MTEs can be given. PROSPERO preregistered (CRD42018090502).

Research in nutritional supplements and nutraceuticals for health, physical activity, and performance: moving forward 1

This Horizons is part of a series that identifies key, forward-thinking research questions and challenges that need to be addressed. Specifically, this Horizons paper discusses research in nutritional supplements and nutraceuticals for health, physical activity, and performance, and is the product of a discussion by an expert panel that took place in January 2018 prior to the Canadian Nutrition Society Thematic Conference "Advances in Sport Nutrition from Daily Living to High Performance Sport". The objective of this Horizons paper was to identify core considerations for future studies for this research area, and how scientists can be leaders in the field to ensure the best quality science is available for decision makers. It is strongly recommended that the various elements highlighted throughout this Horizons paper will increase the awareness of the significant before-, during-, and after-research due-diligence required to produce research of the highest quality. While it is recognized that many scientists will not be able to meet all of these aspects, it is nonetheless important to consider the points outlined and to recognize that those elements that are not met in studies may be significant limitations. Highlights Research questions that are hypothesis-driven are the strongest, and when combined with careful planning of the study, the result will often be of the best quality. Studies with a strong experimental design help discern between evidence-based findings and those that have not been substantiated.

Using the Dietary Supplement Label Database to Identify Potentially Harmful Dietary Supplement Ingredients

Over half of young adults, athletes, and Military Service Members self-report using at least one dietary supplement (DS) 1 or more times per week. DS may be consumed to improve health, provide more energy, increase muscle strength, and/or enhance performance. The United States Food and Drug Administration (FDA) has raised concerns regarding adulteration, safety, and adverse events associated with DS marketed for brain health and bodybuilding. Some DS products may compromise health as well as lead to a serious adverse event. The National Institutes of Health (NIH) Dietary Supplement Label Database (DSLD), available at https://dsld.nlm.nih.gov/, can be freely accessed and used by researchers, providers, and consumers alike to screen for potentially harmful DS. It was developed to serve the research community and as a resource for health care providers and the public. Herein we provide two examples of how the database can be used to identify DS ingredients of concern in products marketed for brain health and bodybuilding. The search for DS marketed for brain health returned 49 unique DS, and the search on DS marketed for bodybuilding returned 18 unique DS. Search results were cross-referenced with the Operation Supplement Safety High-Risk Supplement List, the FDA Tainted Products Marketed as Dietary Supplements list, the Natural Medicines database, and NIH Office of Dietary Supplements Fact Sheets. Three ingredients found in DS marketed for brain health and two ingredients in DS marketed for bodybuilding were identified as "of concern". Educational tools, including the DSLD, can help consumers and providers make informed decisions regarding DS.

Sports Foods and Dietary Supplements for Optimal Function and Performance Enhancement in Track-and-Field Athletes

Athletes are exposed to numerous nutritional products, attractively marketed with claims of optimizing health, function, and performance. However, there is limited evidence to support many of these claims, and the efficacy and safety of many products is questionable. The variety of nutritional aids considered for use by track-and-field athletes includes sports foods, performance supplements, and therapeutic nutritional aids. Support for sports foods and five evidence-based performance supplements (caffeine, creatine, nitrate/beetroot juice, β-alanine, and bicarbonate) varies according to the event, the specific scenario of use, and the individual athlete's goals and responsiveness. Specific challenges include developing protocols to manage repeated use of performance supplements in multievent or heat-final competitions or the interaction between several products which are used concurrently. Potential disadvantages of supplement use include expense, false expectancy, and the risk of ingesting banned substances sometimes present as contaminants. However, a pragmatic approach to the decision-making process for supplement use is recommended. The authors conclude that it is pertinent for sports foods and nutritional supplements to be considered only where a strong evidence base supports their use as safe, legal, and effective and that such supplements are trialed thoroughly by the individual before committing to use in a competition setting.

Acute Supplementation with Molecular Hydrogen Benefits Submaximal Exercise Indices. Randomized, Double-Blinded, Placebo-Controlled Crossover Pilot Study

Background

Clinical studies have reported hydrogen-rich water (HRW) to have therapeutic and ergogenic effects. The aim of this study was to determine the effect of acute supplementation with HRW on exercise performance as measured by VO₂, respiratory exchange ratio (RER), heart rate (HR), and respiratory rate (RR).

Methods

Baseline levels of all exercise indices were determined in nineteen (4 female, 23.4 ± 9.1 yr; 15 male, 30.5 ± 6.8 yr) healthy subjects using a graded treadmill exercise test to exhaustion. Each subject was examined two additional times in a randomized double-blinded, placebo-controlled crossover fashion. Subjects received either HRW or placebo, which was consumed the day before and the day of the testing. HRW was delivered using the hydrogen-producing tablets, DrinkHRW (5 mg of H₂). All data was analyzed with SPSS using pairwise comparisons with Bonferroni adjustment.

Results

HRW supplementation did not influence maximal or minimal indices of exercise performance (VO₂, RER, HR and RR) (p < 0.05). However, HRW significantly decreased average exercising RR and HR (p < 0.05). HRW decreased exercising HR during minutes 1–9 of the graded exercise test (121 ± 26 bpm) compared to placebo (126 ± 26 bpm) and baseline (124 ± 27 bpm) (p < 0.001) without substantially influencing VO₂.

Conclusion

Acute supplementation of DrinkHRW tablets may benefit submaximal aerobic exercise performance by lowering exercising HR. Further studies are needed to determine the influence and practical significance of HRW on varying exercise intensities as well as optimal dosing protocols and the effects of chronic use.

Supplements with purported effects on muscle mass and strength

PURPOSE

Several supplements are purported to promote muscle hypertrophy and strength gains in healthy subjects, or to prevent muscle wasting in atrophying situations (e.g., ageing or disuse periods). However, their effectiveness remains unclear.

METHODS

This review summarizes the available evidence on the beneficial impacts of several popular supplements on muscle mass or strength.

RESULTS

Among the supplements tested, nitrate and caffeine returned sufficient evidence supporting their acute beneficial effects on muscle strength, whereas the long-term consumption of creatine, protein and polyunsaturated fatty acids seems to consistently increase or preserve muscle mass and strength (evidence level A). On the other hand, mixed or unclear evidence was found for several popular supplements including branched-chain amino acids, adenosine triphosphate, citrulline, β-Hydroxy-β-methylbutyrate, minerals, most vitamins, phosphatidic acid or arginine (evidence level B), weak or scarce evidence was found for conjugated linoleic acid, glutamine, resveratrol, tribulus terrestris or ursolic acid (evidence level C), and no evidence was found for other supplements such as ornithine or α-ketoglutarate (evidence D). Of note, although most supplements appear to be safe when consumed at typical doses, some adverse events have been reported for some of them (e.g., caffeine, vitamins, α-ketoglutarate, tribulus terrestris, arginine) after large intakes, and there is insufficient evidence to determine the safety of many frequently used supplements (e.g., ornithine, conjugated linoleic acid, ursolic acid).

CONCLUSION

 In summary, despite their popularity, there is little evidence supporting the use of most supplements, and some of them have been even proven ineffective or potentially associated with adverse effects.