Journal of the International Society of Sports Nutrition

La Monica, Michael B.; Raub, Betsy; Hartshorn, Shelley; Gustat, Ashley L.; Grdic, Jodi; Kirby, Trevor O.; Townsend, Jeremy R.; Sandrock, Jen; Ziegenfuss, Tim N.

doi: 10.1080/15502783.2024.2409682pmid: 39352252

Background This study aimed to examine the effect of a commercially available multi-ingredient powder (AG1Ⓡ) on the gut microbiome and assess the impact of AG1Ⓡ on GI tolerability and other clinical safety markers in healthy men and women. Methods Using a double-blind, randomized, two-arm, placebo-controlled, parallel design, we examined a 4-week daily supplementation regimen of AG1Ⓡ vs. placebo (PL). Fifteen men and 15 women provided stool samples for microbiome analysis, questionnaires for digestive quality of life (DQLQ), and completed visual analog scales (VAS) and Bristol stool charts to assess stool consistency and bowel frequency before and after the 4-week intervention. Participant’s blood work (CBC, CMP, and lipid panel) was also assessed before and after the 4-week intervention. Alpha diversity was determined by Shannon and Chao1 index scores and evaluated by a two-way ANOVA, beta diversity in taxonomic abundances and functional pathways was visualized using partial least squares-discriminant analyses and statistically evaluated by PERMANOVA. To identify key biomarkers, specific feature differences in taxonomic relative abundance and normalized functional pathway counts were analyzed by linear discriminant analysis (LDA) effect size (LEfSe). Questionnaires, clinical safety markers, and hemodynamics were evaluated by mixed factorial ANOVAs with repeated measures. This study was registered on clinicaltrials.gov (NCT06181214). Results AG1Ⓡ supplementation enriched two probiotic taxa (Lactobacillus acidophilus and Bifidobacterium bifidum) that likely stem from the probiotics species that exist in the product, as well as L. lactis CH_LC01 and Acetatifactor sp900066565 ASM1486575v1 while reducing Clostridium sp000435835. Regarding community function, AG1Ⓡ showed an enrichment of two functional pathways while diminishing none. Alternatively, the PL enriched six, but diminished five functional pathways. Neither treatment negatively impacted the digestive quality of life via DQLQ, bowel frequency via VAS, or stool consistency via VAS and Bristol. However, there may have been a greater improvement in the DQLQ score (+62.5%, p = 0.058, d = 0.73) after four weeks of AG1Ⓡ supplementation compared to a reduction (−50%) in PL. Furthermore, AG1Ⓡ did not significantly alter clinical safety markers following supplementation providing evidence for its safety profile. Conclusions AG1Ⓡ can be consumed safely by healthy adults over four weeks with a potential beneficial impact in their digestive symptom quality of life.

Chen, Bin; Ding, Li; Qin, Qiyang; Lei, Tze-Huan; Girard, Olivier; Cao, Yinhang

doi: 10.1080/15502783.2024.2363789pmid: 38836626

Background Caffeine, widely recognized as an ergogenic aid, has undergone extensive research, demonstrating its effectiveness to enhance endurance performance. However, there remains a significant gap in systematically evaluating its effects on time trial (TT) performance in cyclists. Purpose This meta-analysis aimed to determine the efficacy of caffeine ingestion to increase cycling TT performance in cyclists and to evaluate the optimal dosage range for maximum effect. Methods A search of four databases was completed on 1 December 2023. The selected studies comprised crossover, placebo-controlled investigations into the effects of caffeine ingestion on cycling TT performance. Completion time (Time) and mean power output (MPO) were used as performance measures for TT. Meta-analyses were performed using a random-effects model to assess the standardized mean differences (SMD) in individual studies. Results Fifteen studies met the inclusion criteria for the meta-analyses. Subgroup analysis showed that moderate doses of caffeine intake (4–6 mg/kg) significantly improved cycling performance (SMD Time = -0.55, 95% confidence interval (CI) = -0.84 ~ -0.26, p < 0.01, I 2 = 35%; SMD MPO = 0.44, 95% CI = 0.09 ~ 0.79, p < 0.05, I 2 = 39%), while the effects of low doses (1–3 mg/kg) of caffeine were not significant (SMD Time = -0.34, 95% CI = -0.84 ~ 0.17, p = 0.19, I 2 = 0%; SMD MPO = 0.31, 95% CI = -0.02 ~ 0.65, p = 0.07, I 2 = 0%). Conclusion A moderate dosage (4–6 mg/kg) of caffeine, identified as the optimal dose range, can significantly improve the time trial performance of cyclists, while a low dose (1–3 mg/kg) does not yield improvement. In addition, the improvements in completion time and mean power output resulting from a moderate dose of caffeine are essentially the same in cycling time trails.

Seo, Ji-Won; Jiang, Shu; Ahn, Soyoung; Kang, Yu Seon; Sung, Yunho; Li, Xinxing; Jamrasi, Parivash; Sun, Eun Mi; Yoo, Jihee; Kim, Byung-Yong; Sim, Hyunsu; Song, Wook

doi: 10.1080/15502783.2024.2393368pmid: 39166753

Background As a relatively novel approach to enhancing skeletal muscle health, mixed protein supplementation has shown similar responses to whey protein. However, no previous studies have examined its impact on golf swing performance. This study aimed to examine the effect of mixed protein supplementation on the swing performance and muscle strength of casual golfers. Methods Sixty participants with a handicap of less than 20 were recruited and randomly assigned to a double-blind, placebo-controlled study design. The participants were divided into two groups: a mixed protein group (MG, n = 30), and a placebo control group (CG, n = 30). They were instructed to ingest either a supplement containing casein calcium, whey protein, and isolated pea protein, or a placebo, once daily for 8 weeks. Pre- and posttests consisted of anthropometric measurements, muscle strength (isokinetic knee and trunk strength, and handgrip strength), 2-minute push-ups, balance, and golf swing performance using a driver and 7-iron. Results After the 8-week supplementation period, ANCOVA, using baseline values as covariates, revealed significant differences for driver distance (p = .004) and driver ball speed (p < .001). MG significantly increased driver distance by 5.17 ± 12.8 m (p = .046), driver ball speed by 1.36 ± 2.87 m/s (p = .021). Additionally, significantly improvements were observed in hand grip strength (+2.12 ± 3.47 kg, p = .004), two-minute push-ups (+4.89 ± 8.14 reps, p = .004), and balance score (−0.37 ± 0.69 min, p = .009). No significant differences were observed in body composition parameters (p > .05). Conclusion The intake of a mixed protein containing both animal and plant proteins had positive effects on golf performance and muscle function. Therefore, mixed proteins may represent a safe and effective approach to enhancing skeletal muscle health in golf players.

Ribeiro, Alex S.; Sofiati, Sandro L.; Kassiano, Witalo; Martinho, Diogo V.; Nascimento, Matheus A.; Avelar, Ademar; Trindade, Michele C. C.; Mayhew, Jerry L.; Cyrino, Edilson S.

doi: 10.1080/15502783.2024.2357319pmid: 38940017

Background This study aimed to determine the agreement between fat-free mass (FFM) estimates from bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) and their use in estimating resting metabolic rate (RMR) in men undergoing resistance training. Methods Thirty healthy resistance-trained men (22.7 ± 4.4 years, 70.0 ± 8.7 kg, 174.6 ± 6.7 cm, and 22.9 ± 2.3 kg/m2) were evaluated. The equation developed by Tinsley et al. (RMR = 25.9 × fat-free mass [FFM] + 284) was adopted to calculate the RMR. DXA was used as the reference method for FFM. Results Furthermore, FFM was also estimated by BIA using a spectral device. No significant difference (p > 0.05) was observed between DXA (1884.2 ± 145.5 kcal) and BIA (1849.4 ± 167.7 kcal) to estimate RMR. A positive and significant correlation (r = 0.89, p < 0.05) was observed between DXA and BIA estimates of RMR. The mean difference between methods indicated that BIA presented a bias of −34.8 kcal. Conclusion These findings suggest that using FFM derived from DXA or BIA results in similar RMR estimates in resistance-trained men.

Martinho, Diogo V.; Field, Adam; Naughton, Robert; Ribeiro, Alex S.; Rebelo, André; Gouveia, Élvio R.; Sarmento, Hugo

doi: 10.1080/15502783.2024.2366427pmid: 38961627

Background The purpose of the review was to evaluate the literature exploring nutritional habits and practices in female soccer players. Methods The PRISMA-ScR Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews were followed. Searches of Web of Science, PubMed and Scopus databases were conducted for studies exploring the nutritional habits and practices of female soccer players. Results A total of 72 studies were included in the scoping review. Studies on female soccer players mainly focused on daily energy expenditure, daily energy and macronutrient intake and hydration status. A negative energy balance was consistent across studies, and the ingestion of CHO appears below the current recommendations. Female soccer players are predominately in negative energy balance, which may indicate that they are at risk of low energy availability. A high use of nutritional supplements is apparent in female soccer, whilst a large proportion of players commence training dehydrated. Conclusions The current findings have implications for practitioners relating to the planning, management, monitoring, and implementation of nutritional intake and training and competition schedules.

Kurtz, Jennifer A.; Grazer, Jacob; Wilson, Kathryn; Feresin, Rafaela G.; Doyle, J. Andrew; Middleton, Ryan; Devis, Emma; VanDusseldorp, Trisha A.; Fasczewski, Kimberly; Otis, Jeff

doi: 10.1080/15502783.2024.2416909pmid: 39417670

Background There is growing interest in the use of nutrition and dietary supplements to optimize training and time-trial (TT) performance in cyclists. Separately, quercetin (QCT) and citrulline (CIT) have been used as ergogenic aids to improve oxygen (VO2) kinetics, perceived effort, and cycling TT performance. However, whether the combination of QCT and CIT can provide additive benefits and further enhance cycling performance production is currently unknown. Methods We examined 28-days of QCT + CIT supplementation on TT performance and several performance measures (i.e. mean power, VO2, respiratory exchange ratio (RER), and rate of perceived exertion (RPE)). Forty-eight highly trained cyclists were assigned to one of four supplementation groups: (1) QCT + CIT (QCT: 500 mg, CIT: 3000 g), (2) QCT (500 mg), (3) CIT (3000 mg), or (4) placebo (3500 mg of a zero-calorie flavored crystal light package). Supplements were consumed two times per day for 28 consecutive days. Participants performed a 20-km cycling time-trial race, pre- and post-supplementation to determine the impact of the combined effects of QCT + CIT. Results There were no potential benefits of QCT +CIT supplementation on TT performance and several performance measures. However, there was an improvement in VO2 from pre-to-post-supplementation in QCT (p  = 0.05) and CIT (p  = 0.04) groups, but not in the QCT+CIT and PL groups. Conclusions QCT + CIT does not seem beneficial for 20-km TT performance; further exploration with a focus on an increase in cycling duration or QCT+CIT combined with additional polyphenols may amplify any perceived bioactive or metabolic effects on cycling performance. The efficacy of QCT + CIT supplementation to improve cycling performance remains ambiguous.

Martínez-Noguera, Francisco Javier; Cabizosu, Alessio; Alcaraz, Pedro E.; Marín-Pagán, Cristian

doi: 10.1080/15502783.2024.2346563pmid: 38676933

Background Due to the increase in global temperature, it is necessary to investigate solutions so that athletes competing in hot conditions can perform in optimal conditions avoiding loss of performance and health problems. Therefore, this study aims to evaluate the effect of pre-exercise glycerol supplementation during a rectangular test at ambient temperature mid (28.2ºC) on dehydration variables in international race walkers. Methods Eight international male race walkers (age: 28.0 years (4.4); weight: 65.6 kg (6.6); height: 180.0 cm (5.0); fat mass: 6.72% (0.66); muscle mass: 33.3 kg (3.3); VO2MAX: 66.5 ml · kg−1·min−1 (1.9)) completed this randomized crossover design clinical trial. Subjects underwent two interventions: they consumed placebo (n = 8) and glycerol (n = 8) acutely, before a rectangular test where dehydration, RPE, metabolic, kinematic, and thermographic variables were analyzed before, during and after the test. Results After the intervention, significant differences were found between groups in body mass in favor of the placebo (Placebo: −2.23 kg vs Glycerol: −2.48 kg; p = 0.033). For other variables, no significant differences were found. Conclusion Therefore, pre-exercise glycerol supplementation was not able to improve any dehydration, metabolic, kinematic, or thermographic variables during a rectangular test at temperature mid in international race walkers. Possibly, a higher environmental temperature could have generated a higher metabolic and thermoregulatory stress, generating differences between groups like other previous scientific evidence.

Lopes, Sofia; Cunha, Madalena; Costa, João Guilherme; Ferreira-Pêgo, Cíntia

doi: 10.1080/15502783.2024.2388077pmid: 39114969

Background Gym-goers usually seek methods to improve performance, muscle gain, and overall health. One of the main strategies is including food supplements (FS) into their routine as aids to enhance their athletic capabilities and satisfy their nutritional needs. Thus, this study aimed to investigate and characterize the main FS and Sports Foods (SF) currently consumed, as well as the main reasons for their use and the source of advice in a group of gym-goers in the Lisbon Metropolitan Area (Portugal). Methods A cross-sectional study was conducted, including 303 gym-goers from Lisbon, Portugal, who were 133 women and 170 males (30.8 ± 12.9 years old). Face-to-face interviews were used by qualified researchers to gather data. Results Most of the interviewed athletes (71.95 %) took FS/SF, being men the main consumers. On average, 1.59 supplements were consumed per athlete. Logistic regression models indicated significant associations between age, gender, and motivations for gym attendance. While men and younger groups attended mainly for hypertrophy, women and older groups were focused on well-being. Protein (59.17 %) was the most used FS/SF, followed by creatine (41.28 %) and multivitamins (27.06 %). Men and younger individuals preferred protein and creatine, while older individuals focused more on specific vitamins and minerals. Women seemed to prefer L-carnitine and protein yogurts. Main sources of information included the internet, friends, and dietitians with notable gender and age-based preferences. Online stores were the main place of purchase. Monthly expenditures on FS/SF were not significantly affected by age or gender, but motivations for use had an influence. Conclusion Most of the athletes interviewed took FS/SF, being men the major consumers. Protein was the principal FS/SF used, with online stores being the main place of purchase and the internet the primary source of information. Age and gender were key factors in adopted training, in the FS/SF chosen, and in the source of information selected. It is crucial that health professionals take primary responsibility for providing this guidance.

Wang, Jialu; Song, Anqi; Tang, Molian; Xiang, Yi; Zhou, Yiquan; Chen, Zhiqi; Heber, David; Tang, Qingya; Xu, Renying

doi: 10.1080/15502783.2024.2307963pmid: 38265726

Background A commercial three-dimensional optical (3DO) scanning system was reported to be used in body composition assessment. However, the applicability in Chinese adults has yet to be well-studied. Methods This secondary analysis was based on a 16-week weight-loss clinical trial with an optional extension to 24 weeks. Waist and hip circumference and body composition were measured by 3DO scanning at each follow-up visit during the study. Bioelectrical impedance analysis (BIA) was also performed to confirm the reliability of 3DO scanning at each visit. We used Lin’s concordance correlation coefficients (CCC) to evaluate the correlation between the two methods above-mentioned. Bland-Altman analysis was also performed to evaluate the agreement and potential bias between different methods. Results A total number of 70 Chinese adults overweight and obese (23 men and 47 women, aged 31.8 ± 5.8 years) were included in the analysis, which resulted in 350 3DO scans and corresponding 350 BIA measurements. The percent body fat, fat mass, and fat-free mass were 33.9 ± 5.4%, 26.7 ± 4.6 kg, and 50.3 ± 8.7 kg before the trial by 3DO scanning. And they were 30.5 ± 5.8%, 22.5 ± 4.7 kg, and 49.4 ± 8.3 kg after 16 weeks of the trial. Compared with BIA, 3DO scanning performed best in the assessment of fat-free mass (CCC = 0.89, 95%CI: 0.86, 0.90), then followed by fat mass (CCC = 0.76, 95%CI: 0.71, 0.80) and percent body fat (CCC = 0.70, 95%CI: 0.64, 0.75). Subgroup analysis showed that 3DO scanning and BIA correlated better in women than that in men, and correlated better in measuring fat-free mass in participants with larger body weight (BMI ≥28.0 kg/m2) than those with smaller body weight (<28.0 kg/m2). Conclusions 3DO scanning is an effective technology to monitor changes in body composition in Chinese adults overweight and obese. However its accuracy and reliability in different ethnicities needs further exploration.

Chien, Yu-Jou; Tsao, Jung-Piao; Tsai, Chun-Tse; Cheng, I-Shiung; Hsu, Chin-Lin

doi: 10.1080/15502783.2024.2416479pmid: 39417669

Background Prolonged exercise usually leads to exercise fatigue, which has a negative short-term impact on exercise performance and metabolic rate; thus, fatigue needs to be resolved. Okara is a protein-rich residue of soy processing. Enzyme hydrolysis is known to increase the content of branched-chain amino acids (BCAAs), which have been reported to confer benefits for exercise. The purpose of this study was to investigate the antifatigue effect of okara protein hydrolysate (OPH) on cycling exercise. Methods A total of 16 male participants who habitually exercised (2 times or more per week and without participation in athletic contests) were instructed to receive 11.74 g of OPH once a day. They then completed two intense cycling exercise challenges before and after four weeks of supplementation. Exercise time and blood markers related to fatigue and energy metabolism were measured. Results The results showed that the time to exhaustion significantly increased after the treatment. The levels of lactate during exercise and at the end of exercise were significantly lower after treatment than before. Additionally, postexercise insulin sensitivity was increased after treatment. Conclusions This study showed that OPH supplementation can promote endurance in exercise by decreasing the accumulation of fatigue-related metabolites during exercise and can promote energy recovery by increasing insulin function. These findings suggest that OPH has an antifatigue property.