Jisun Chun

Jisun Chun

*This is an algorithmically generated author record based on publicly available information.

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Jisun Chun has a total of 43 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Age-related Differences In Firefighters’ Cardiorespiratory Fitness And Body Composition: A Single, Large-scale, Metropolitan-departmental Study

    by Jisun Chun, Kelly Hines, Michael J. Conner, Brian Newman, Steven E. Martin, Lisa Colvin, Drew E. Gonzalez

    Was not provided for this article.

  • Open Access

    Effects of a Plant-Based Multi-Strain Limosilactobacillus fermentum Probiotic on Weight Loss Outcomes in Overweight and Obese Adults: A Preliminary Study

    by Sarah Johnson, Broderick L. Dickerson, Jisun Chun, Olivia Haskell, Elena Chavez, Leah Kirkegaard, Kelly Elizabeth Hines, Choongsung Yoo, Joungbo Ko, Dante Xing, et al.

    Background/Objectives: Multi-strain Limosilactobacillus fermentum supplementation has been reported to promote weight loss outcomes in free-living conditions, but limited evidence exists on these probiotic strains added to an energy-restricted diet and walking program in overweight adults. Methods: In a double-blind, placebo-controlled, parallel-arm randomized trial, overweight adults (35.2 ± 13.2 years old, 167.6 ± 8.6 cm, 79.9 ± 11.8 kg, 28.4 ± 2.7 kg/m2 body mass index, 36.1 ± 6.6% body fat) completed a 12-week weight loss program that included a 500 kcal/day energy deficit and walking 10 k steps/d. Participants ingested one daily capsule containing a three-strain probiotic blend (L. fermentum K7-Lb1, L. fermentum K8-Lb1, L. fermentum K11-Lb3; 6 billion CFU/day) (PRO) or maltodextrin placebo (PLA). Assessments were performed at baseline, week 6, and week 12 and included body composition, resting energy expenditure, substrate utilization, peak oxygen uptake, dietary intake, step counts, blood biomarkers, quality of life, and side effects. Data were analyzed using multivariate and univariate repeated-measures general linear models (GLM), with mean changes from baseline presented alongside 95% confidence intervals. Results: All participants significantly reduced body weight, fat mass, body fat percentage, and waist circumference. At 12 weeks, PRO reduced fat mass more than PL (−2680.7 ± 1276.7 g; p = 0.039). In PRO, android and gynoid fat percentage decreased at 6 weeks (p < 0.001; p = 0.008) and 12 weeks (p = 0.004; p < 0.001), respectively. Visceral adipose tissue mass, volume, and area were lower at 6 weeks and trended lower at 12 weeks. In PRO, bone mineral content and bone mineral area decreased at 12 weeks, while bone mineral density paradoxically increased (0.007 ± 0.003 g/cm2; p = 0.024). Conclusions: During a 12-week weight loss program, supplementation of a multi-strain L. fermentum probiotic significantly reduced body fat and central adiposity.


  • Open Access

    Creatine Supplementation Dose and Duration Are Not Associated with Increased Side Effects: A Structured Review and Study-Level Dose–Response Analysis of Randomized Controlled Trials

    by Drew E. Gonzalez, Broderick L. Dickerson, Kelly Hines, Jisun Chun, Adriana Gil, Scott C. Forbes, Darren G. Candow, Richard B. Kreider

    There are concerns that high-dose and/or long-term creatine monohydrate supplementation (CrM) leads to greater side effects (SEs) compared to placebo. This analysis investigated whether the dose or duration of CrM was associated with SEs. Data from trials involving more than 12,800 participants within CrM and placebo study arms of 684 randomized clinical trials were analyzed. SEs were combined into categories and total absolute dose and CrM duration were grouped into tertiles (low, moderate, and high). Crosstabs with chi-square tests were used to compare the prevalence of SEs across CrM dose and duration tertiles. Logistic regression models, adjusted for biological sex, age, and population categories, were used to test dose and duration as continuous predictors. Across 684 randomized controlled trials, reported SEs were infrequent. Although dose and duration tertiles were statistically associated with study-level side effect reporting, the effect sizes were uniformly small, events were infrequent, and the reported symptoms were primarily mild and nonspecific. No consistent exposure–response pattern indicative of clinically meaningful risk was observed. Adjusted logistic regression and frequency-based analyses showed no consistent dose- or duration-dependent increase in SE risk, with placebo groups often reporting similar or greater SE frequencies at the study-reporting level. CrM appears to be well-tolerated and, at the study-level, does not increase the risk of gastrointestinal, renal, liver, musculoskeletal, or other SEs compared to placebo, even at high doses or longer durations.


  • Open Access

    Impact of Age and Years in the Fire Service on Firefighter Health and Physical Performance Outcomes

    by Jisun Chun, Michael J. Conner, Jacob A. Mota, Brian Newman, J. Jay Dawes, Steven E. Martin, Drew Edward Gonzalez

    Background: Age is considered an independent cardiovascular disease (CVD) risk factor, but limited data exist concerning the impact of age and years in the fire service on firefighter health and physical performance. Objectives: We assessed the impact of age and years in the fire service on structural firefighter health and physical performance. Methods: 142 firefighters completed an annual clinical assessment. General linear model (GLM) multivariate and univariate analyses were performed across age groups, with years of fire service experience as a covariate. Partial Eta squared (ηp2) values for the GLM statics and Cohen’s d for pairwise comparisons were used to assess effect size. Results: GLM analyses revealed statistically significant differences (p < 0.05) for several demographic, body composition, blood biomarker, and physical performance parameters. Pairwise comparisons revealed that younger firefighters displayed more favorable health and fitness profiles than their older counterparts. Interestingly, when accounting for years of fire service experience, differences for only the following variables remained: body mass index, waist circumference, lean mass, visceral adipose tissue, triglycerides, cardiopulmonary exercise test time-to-exhaustion, and VO2max. Conclusions: These findings suggest differences in CVD risk biomarkers, physical fitness levels, and body composition metrics across age groups. However, years of fire service experience appears to have a greater impact on these variables, suggesting that firefighters’ time in the fire service may accelerate the effects of aging on these outcomes. While age-specific health interventions are recommended to manage and mitigate CVD risk effectively, there also should be consideration for the years of fire service.


  • Open Access

    Effects of 12 Weeks of Chromium, Phyllanthus emblica Fruit Extract, and Shilajit Supplementation on Markers of Cardiometabolic Health, Fitness, and Weight Loss in Men and Women with Risk Factors to Metabolic Syndrome Initiating an Exercise and Diet Intervention: A Randomized Double-Blind, Placebo-Controlled Trial

    by Victoria Martinez, Kay McAngus, Broderick L. Dickerson, Megan Leonard, Elena Chavez, Jisun Chun, Megan Lewis, Dante Xing, Drew E. Gonzalez, Choongsung Yoo, et al.

    Background: Exercise and nutritional interventions are often recommended to help manage risk related to metabolic syndrome (MetSyn). The co-ingestion of Phyllanthus emblica (PE) with trivalent chromium (Cr) has been purported to improve the bioavailability of chromium and enhance endothelial function, reduce platelet aggregation, and help manage blood glucose as well as lipid levels. Shilajit (SJ) has been reported to have anti-inflammatory, adaptogenic, immunomodulatory, and lipid-lowering properties. This study evaluated whether dietary supplementation with Cr, PE, and SJ, or PE alone, during an exercise and diet intervention may help individuals with risk factors to MetSyn experience greater benefits. Methods: In total, 166 sedentary men and women with at least two markers of metabolic syndrome participated in a randomized, placebo-controlled, parallel-arm, and repeated-measure intervention study, of which 109 completed the study (48.6 ± 10 yrs., 34.2 ± 6 kg/m2, 41.3 ± 7% fat). All volunteers participated in a 12-week exercise program (supervised resistance and endurance exercise 3 days/week with walking 10,000 steps/day on non-training days) and were instructed to reduce energy intake by −5 kcals/kg/d. Participants were matched by age, sex, BMI, and body mass for the double-blind and randomized supplementation of a placebo (PLA), 500 mg of PE (PE-500), 1000 mg/d of PE (PE-1000), 400 µg of trivalent chromium (Cr) with 6 mg of PE and 6 mg of SJ (Cr-400), or 800 µg of trivalent chromium with 12 mg of PE and 12 mg of SJ (Cr-800) once a day for 12 weeks. Data were obtained at 0, 6, and 12 weeks of supplementation, and analyzed using general linear model multivariate and univariate analyses with repeated measures, pairwise comparisons, and mean changes from the baseline with 95% confidence intervals (CIs). Results: Compared to PLA responses, there was some evidence (p < 0.05 or approaching significance, p > 0.05 to p < 0.10) that PE and/or Cr with PE and SJ supplementation improved pulse wave velocity, flow-mediated dilation, platelet aggregation, insulin sensitivity, and blood lipid profiles while promoting more optimal changes in body composition, strength, and aerobic capacity. Differences among groups were more consistently seen at 6 weeks rather than 12 weeks. While some benefits were seen at both dosages, greater benefits were more consistently observed with PE-1000 and Cr-800 ingestion. Conclusions: The results suggest that PE and Cr with PE and SJ supplementation may enhance some exercise- and diet-induced changes in markers of health in overweight individuals with at least two risk factors to MetSyn. Registered clinical trial #NCT06641596.


  • Open Access

    Effects of Pork Protein Ingestion Prior to and Following Performing the Army Combat Fitness Test on Markers of Catabolism, Inflammation, and Recovery

    by Drew E. Gonzalez, Kelly E. Hines, Ryan J. Sowinski, Landry Estes, Sarah E. Johnson, Jisun Chun, Hudson Lee, Sheyla Leon, Adriana Gil, Joungbo Ko, et al.

    Tactical athletes and military personnel engaged in intense exercise need to consume enough quality protein in their diet to maintain protein balance and promote recovery. Plant-based protein sources contain fewer essential amino acids (EAAs), while pork loin contains a higher concentration of EAAs and creatine than most other animal protein sources. This study aimed to determine whether the ingestion of plant-based or pork-based military-style meals ready-to-eat (MREs) affects recovery from and subsequent Army Combat Fitness Test (ACFT) performance. Methods: Twenty-three (n = 23) University Corps of Cadets members participated in a randomized, double-blind, placebo-controlled, and crossover-designed study. Diets were prepared by a dietitian, food scientist, and chef to have similar taste, appearance, texture, and macronutrient content. The chef also labeled the meals for double-blind administration. Participants refrained from intense exercise for 48 h before reporting to the lab in a fasted condition with a 24 h urine sample. Participants donated a blood sample, completed questionnaires and cognitive function tests, and consumed a pre-exercise meal. After four hours, participants performed the ACFT according to military standards. Participants were fed three MREs daily while returning to the lab in a fasted condition at 0600 with 24 h urine samples after 24, 48, and 72 h of recovery. On day 3, participants repeated the ACFT four hours after consuming an MRE for breakfast. Participants resumed normal training and returned to the lab after 2–3 weeks to repeat the experiment while consuming the alternate diet. Data were analyzed using general linear model statistics with repeated measures and percent changes from baseline with 95% confidence intervals. Results: Results revealed that 3 days were sufficient for participants to replicate ACFT performance. However, those consuming the pork-based diet experienced less muscle soreness, urinary urea excretion, cortisol, inflammation, and depression scores while experiencing a higher testosterone/cortisol ratio and appetite satisfaction. There was also evidence of more favorable changes in red and white blood cells. Conversely, blood lipid profiles were more favorably changed when following a plant-based diet. Conclusions: These findings suggest that protein quality and the availability of creatine in the diet can affect recovery from intense military-style exercise. Minimally, plant-based MREs should include 6–10 g/d of EAA and 2–3 g/d of creatine monohydrate to offset dietary deficiencies, particularly in military personnel following a vegetarian diet. Registered clinical trial #ISRCTN47322504.


  • Open Access

    Effects of Supplementation with a Microalgae Extract from Phaeodactylum tricornutum Containing Fucoxanthin on Cognition and Markers of Health in Older Individuals with Perceptions of Cognitive Decline

    by Choongsung Yoo, Jonathan Maury, Drew E. Gonzalez, Joungbo Ko, Dante Xing, Victoria Jenkins, Broderick Dickerson, Megan Leonard, Landry Estes, Sarah Johnson, et al.

    Phaeodactylum tricornutum (PT) is a microalgae extract that contains fucoxanthin and has been shown to enhance cognitive function in younger populations. The present study assessed if PT supplementation affects cognition in healthy, young-old, physically active adults with self-perceptions of cognitive and memory decline. Methods: Forty-three males and females (64.3 ± 6.0 years, 79.8 ± 16.0 kg, 27.0 ± 4.0 kg/m2) with perceptions of cognitive and memory decline completed the double-blind, randomized, parallel-arm, placebo-controlled intervention clinical trial. Participants were counterbalanced by sex and BMI and randomly allocated to their respective 12-week supplementation interventions, which were either the placebo (PL) or 1100 mg/day of PT containing 8.8 mg of fucoxanthin (FX). Fasting blood samples were collected, and cognitive assessments were performed during the testing session at 0, 4, and 12 weeks of intervention. The data were analyzed by multivariate and univariate general linear model (GLM) analyses with repeated measures, pairwise comparisons, and mean changes from baseline analysis with 95% confidence intervals (CIs) to assess the clinical significance of the findings. Results: FX supplementation significantly affected (p < 0.05) or exhibited tendencies toward significance (p > 0.05 to p < 0.10 with effect sizes ranging from medium to large) for word recall, picture recognition reaction time, Stroop color–word test, choice reaction time, and digit vigilance test variables. Additionally, FX supplementation promoted a more consistent clinical improvement from baseline values when examining mean changes with 95% CIs, although most differences were seen over time rather than between groups. Conclusions: The results demonstrate some evidence that FX supplementation can improve working and secondary memory, vigilance, attention, accuracy, and executive function. There was also evidence that FX promoted more positive effects on insulin sensitivity and perceptions about sleep quality with no negative effects on clinical blood panels or perceived side effects. Additional research should investigate how FX may affect cognition in individuals perceiving memory and cognitive decline. Registered clinical trial #NCT05759910.