Publications by authors named "Choongsung Yoo"

7 Publications

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Dose-Response of Paraxanthine on Cognitive Function: A Double Blind, Placebo Controlled, Crossover Trial.

Nutrients 2021 Dec 15;13(12). Epub 2021 Dec 15.

Exercise & Sport Nutrition Lab, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843, USA.

Paraxanthine (PXN) is a metabolite of caffeine that has recently been reported to enhance cognition at a dose of 200 mg.

Objective: To determine the acute and short-term (7-day) effects of varying doses of PXN on cognitive function and side effects.

Methods: In a double blind, placebo-controlled, crossover, and counterbalanced manner, 12 healthy male and female volunteers (22.7 ± 4 years, 165 ± 7 cm, 66.5 ± 11 kg, 24.4 ± 3 kg/m) ingested 200 mg of a placebo (PLA), 50 mg of PXN (ENFINITY™, Ingenious Ingredients, L.P.) + 150 mg PLA, 100 mg PXN + 100 mg PLA, or 200 mg of PXN. With each treatment experiment, participants completed side effect questionnaires and donated a fasting blood sample. Participants then performed a series of tests assessing cognition, executive function, memory, and reaction time. Participants then ingested one capsule of PLA or PXN treatments. Participants then completed side effects and cognitive function tests after 1, 2, 3, 4, 5, and 6 h of treatment ingestion. Participants continued ingesting one dose of the assigned treatment daily for 6-days and returned to the lab on day 7 to donate a fasting blood sample, assess side effects, and perform cognitive function tests. Participants repeated the experiment while ingesting remaining treatments in a counterbalanced manner after at least a 7-day washout period until all treatments were assessed.

Results: The Sternberg Task Test (STT) 4-Letter Length Present Reaction Time tended to differ among groups ( = 0.06). Assessment of mean changes from baseline with 95% CI's revealed several significant differences among treatments in Berg-Wisconsin Card Sorting Correct Responses, Preservative Errors (PEBL), and Preservative Errors (PAR Rules). There was also evidence of significant differences among treatments in the Go/No-Go Task tests in Mean Accuracy as well as several time points of increasing complexity among STT variables. Finally, there was evidence from Psychomotor Vigilance Task Test assessment that response time improved over the series of 20 trials assessed as well as during the 6-h experiment in the PXN treatment. Acute and short-term benefits compared to PLA were seen with each dose studied but more consistent effects appeared to be at 100 mg and 200 mg doses. No significant differences were observed among treatments in clinical chemistry panels or the frequency or severity of reported side effects. Results provide evidence that acute ingestion of 100 mg and 200 mg of PXN may affect some measures of cognition, memory, reasoning, and response time as well as help sustain attention. Additionally, that acute and daily ingestion of PXN for 7 days is not associated with any clinically significant side effects.

Conclusions: PXN may serve as an effective nootropic agent at doses as low as 50 mg.
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http://dx.doi.org/10.3390/nu13124478DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8708375PMC
December 2021

Acute Paraxanthine Ingestion Improves Cognition and Short-Term Memory and Helps Sustain Attention in a Double-Blind, Placebo-Controlled, Crossover Trial.

Nutrients 2021 Nov 9;13(11). Epub 2021 Nov 9.

Human Clinical Research Facility, Exercise & Sport Nutrition Lab, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843, USA.

This study examined the effects of acute paraxanthine (PXN) ingestion on markers of cognition, executive function, and psychomotor vigilance. In a randomized, double blind, placebo-controlled, crossover, and counterbalanced manner, 13 healthy male and female participants were randomly assigned to consume a placebo (PLA) or 200 mg of PXN (ENFINITY™, Ingenious Ingredients, L.P.). Participants completed stimulant sensitivity and side effect questionnaires and then performed the Berg Wisconsin Card Sorting Test (BCST), the Go/No-Go test (GNG), the Sternberg task test (STT), and the psychomotor vigilance task test (PVTT). Participants then ingested one capsule of PLA or PXN treatment. Participants completed side effect and cognitive function tests after 1, 2, 3, 4, 5, and 6 h after ingestion of the supplement. After 7 days, participants repeated the experiment while consuming the alternative treatment. Data were analyzed by general linear model (GLM) univariate analyses with repeated measures using body mass as a covariate, and by assessing mean and percent changes from baseline with 95% confidence intervals (CIs) expressed as means (LL, UL). PXN decreased BCST errors (PXN -4.7 [-0.2, -9.20], = 0.04; PXN -17.5% [-36.1, 1.0], = 0.06) and perseverative errors (PXN -2.2 [-4.2, -0.2], = 0.03; PXN -32.8% [-64.4, 1.2], = 0.04) at hour 6. GNG analysis revealed some evidence that PXN ingestion better maintained mean accuracy over time and Condition R Round 2 response time (e.g., PXN -25.1 [-52.2, 1.9] ms, = 0.07 faster than PLA at 1 h), suggesting better sustained attention. PXN ingestion improved STT two-letter length absent and present reaction times over time as well as improving six-letter length absent reaction time after 2 h (PXN -86.5 ms [-165, -7.2], = 0.03; PXN -9.0% [-18.1, 0.2], = 0.05), suggesting that PXN enhanced the ability to store and retrieve random information of increasing complexity from short-term memory. A moderate treatment x time effect size (η = 0.08) was observed in PVTT, where PXN sustained vigilance during Trial 2 after 2 h (PXN 840 ms [103, 1576], = 0.03) and 4 h (PXN 1466 ms [579, 2353], = 0.002) compared to PL. As testing progressed, the response time improved during the 20 trials and over the course of the 6 h experiment in the PXN treatment, whereas it significantly increased in the PL group. The results suggest that acute PXN ingestion (200 mg) may affect some measures of short-term memory, reasoning, and response time to cognitive challenges and help sustain attention.
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http://dx.doi.org/10.3390/nu13113980DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8622427PMC
November 2021

Effects of Inositol-Enhanced Bonded Arginine Silicate Ingestion on Cognitive and Executive Function in Gamers.

Nutrients 2021 Oct 24;13(11). Epub 2021 Oct 24.

Exercise & Sport Nutrition Laboratory, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843, USA.

Inositol stabilized arginine silicate (ASI) ingestion has been reported to increase nitric oxide levels while inositol (I) has been reported to enhance neurotransmission. The current study examined whether acute ASI + I (Inositol-enhanced bonded arginine silicate) ingestion affects cognitive function in e-sport gamers. In a double blind, randomized, placebo controlled, and crossover trial, 26 healthy male (n = 18) and female (n = 8) experienced gamers (23 ± 5 years, 171 ± 11 cm, 71.1 ± 14 kg, 20.7 ± 3.5 kg/m) were randomly assigned to consume 1600 mg of ASI + I (nooLVL, Nutrition 21) or 1600 mg of a maltodextrin placebo (PLA). Prior to testing, participants recorded their diet, refrained from consuming atypical amounts of stimulants and foods high in arginine and nitrates, and fasted for 8 h. During testing sessions, participants completed stimulant sensitivity questionnaires and performed cognitive function tests (i.e., Berg-Wisconsin Card Sorting task test, Go/No-Go test, Sternberg Task Test, Psychomotor Vigilance Task Test, Cambridge Brain Sciences Reasoning and Concentration test) and a light reaction test. Participants then ingested treatments in a randomized manner. Fifteen minutes following ingestion, participants repeated tests (Pre-Game). Participants then played their favorite video game for 1-h and repeated the battery of tests (Post-Game). Participants observed a 7-14-day washout period and then replicated the study with the alternative treatment. Data were analyzed by General Linear Model (GLM) univariate analyses with repeated measures using weight as a covariate, paired -tests (not adjusted to weight), and mean changes from baseline with 95% Confidence Intervals (CI). Pairwise comparison revealed that there was a significant improvement in Sternberg Mean Present Reaction Time (ASI + I vs. PLA; < 0.05). In Post-Game assessments, 4-letter Absent Reaction Time ( < 0.05), 6-letter Present Reaction Time ( < 0.01), 6-letter Absent Reaction Time ( < 0.01), Mean Present Reaction Time ( < 0.02), and Mean Absent Reaction Time ( < 0.03) were improved with ASI + I vs. PLA. There was a non-significant trend in Pre-Game Sternberg 4-letter Present Reaction time in ASI + I vs. PLA ( < 0.07). ASI + I ingestion better maintained changes in Go/No-Go Mean Accuracy and Reaction Time, Psychomotor Vigilance Task Reaction Time, and Cambridge Post-Game Visio-spatial Processing and Planning. Results provide evidence that ASI + I ingestion prior to playing video games may enhance some measures of short-term and working memory, reaction time, reasoning, and concentration in experienced gamers.
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http://dx.doi.org/10.3390/nu13113758DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8618773PMC
October 2021

The Effects of Exogenous Lactate Administration on the IGF1/Akt/mTOR Pathway in Rat Skeletal Muscle.

Int J Environ Res Public Health 2020 10 25;17(21). Epub 2020 Oct 25.

Department of Physical Education, Konkuk University, Gwangjin-gu, Seoul 05029, Korea.

We investigated the effects of oral lactate administration on protein synthesis and degradation factors in rats over 2 h after intake. Seven-week-old male Sprague-Dawley rats were randomly divided into four groups ( = 8/group); their blood plasma levels of lactate, glucose, insulin, and insulin-like growth factor 1 (IGF1) were examined following sacrifice at 0, 30, 60, or 120 min after sodium lactate (2 g/kg) administration. We measured the mRNA expression levels of protein synthesis-related genes (IGF receptor, protein kinase B (Akt), mammalian target of rapamycin (mTOR)) or degradation-related genes (muscle RING-finger protein-1 (MuRF1), atrogin-1) and analyzed the protein expression and phosphorylation (activation) of Akt and mTOR. Post-administration, the plasma lactate concentration increased to 3.2 mmol/L after 60 min. Plasma glucose remained unchanged throughout, while insulin and IGF1 levels decreased after 30 min. The mRNA levels of IGF receptor and mTOR peaked after 60 min, and Akt expression was significantly upregulated from 30 to 120 min. However, MuRF1 and atrogin-1 expression levels were unaffected. Akt protein phosphorylation did not change significantly, whereas mTOR phosphorylation significantly increased after 30 min. Thus, lactate administration increased the mRNA and protein expression of protein-synthesis factors, suggesting that it can potentially promote skeletal muscle synthesis.
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http://dx.doi.org/10.3390/ijerph17217805DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7663284PMC
October 2020

Effects of exogenous lactate administration on fat metabolism and glycogen synthesis factors in rats.

Phys Act Nutr 2020 Jun;24(2):1-5

Purpose: Lactate has several beneficial roles as an energy resource and in metabolism. However, studies on the effects of oral administration of lactate on fat metabolism and glycogen synthesis are limited. Therefore, the purpose of the present study was to investigate how oral administration of lactate affects fat metabolism and glycogen synthesis factors at specific times (0, 30, 60, 120 min) after intake.

Methods: Male Sprague Dawley (SD) rats (n = 24) were divided into four groups as follows: the control group (0 min) was sacrificed immediately after oral lactate administration; the test groups were administered lactate (2 g/kg) and sacrificed after 30, 60, and 120 min. Skeletal muscle and liver mRNA expression of GLUT4, FAT/CD36, PDH, CS, PC and GYS2 was assessed using reverse transcription-polymerase chain reaction.

Results: GLUT4 and FAT/CD36 expression was significantly increased in skeletal muscle 120 min after lactate administration. PDH expression in skeletal muscle was altered at 30 and 120 min after lactate consumption, but was not significantly different compared to the control. CS, PC and GYS2 expression in liver was increased 60 min after lactate administration.

Conclusion: Our results indicate that exogenous lactate administration increases GLUT4 and FAT/CD36 expression in the muscle as well as glycogen synthase factors (PC, GYS2) in the liver after 60 min. Therefore, lactate supplementation may increase fat utilization as well as induce positive effects on glycogen synthesis in athletes.
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http://dx.doi.org/10.20463/pan.2020.0008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7451839PMC
June 2020

Effect of acute mid-intensity treadmill exercise on the androgen hormone level and uncoupling protein-1 expression in brown fat tissue of mouse.

J Exerc Nutrition Biochem 2018 Mar;22(1):15-21

Purpose: Brown adipose tissue (BAT) plays an important role in metabolizing different substances, including androgens. The aim of this study was to determine whether a single bout of aerobic exercise would increase the androgen hormone concentration in mouse BAT and whether its increase was associated with uncoupling protein-1 (UCP-1), protein kinase A (PKA)-related mechanism in BAT.

Methods: Twenty, 9-week-old ICR adult male micewere randomly divided into three groups: Control (n=6, CON), Exercise (n=7, EX), and Exercise + SRD5A1A2 inhibitor (n=7, EXIN). SRD5A1A2 is an enzyme needed when free testosterone is metabolized to dihydrotestosterone (DHT). SRD5A1A2 was administered intraperitoneally in the EXIN group, while the CON and EX groups were treated with the vehicle only. One hour later, exercise was performed at 60-70% V̇O2max for 30minutes. The levels of testosterone and DHT in BAT were determined by ELISA, and UCP-1 mRNA level was examined by RT-PCR. UCP-1 and PKA protein levels were determined by western blotting.

Results: After a single period of exercise, testosterone and DHT concentrations in BAT were significantly higher in EX than those in CON, and lower in EXIN than those in EX. The ratio of phosphorylated PKA to total PKA in BAT was significantly higher in EX than that in CON, and lower in EXIN than that in EX. UCP-1 levels in BAT were not different in the three groups.

Conclusion: Aerobic exercise increased bioactive androgen hormone levels in BAT in association with the increase in phosphorylated PKA levels. In contrast, 30minutes of treadmill exercise did not affect UCP-1 expression.
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http://dx.doi.org/10.20463/jenb.2018.0003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5909077PMC
March 2018

The synergistic effect of protein complex supplementation combined with 12 weeks of resistance training on isokinetic muscular function in untrained young males.

J Exerc Nutrition Biochem 2017 Dec;21(4):27-36

Purpose: Resistance exercise training (RET) and an additional intake of dietary protein supplements may improve muscle mass and muscular function, and reduce inflammatory markers. The types, amount, and timing of dietary protein supplements are important for the synergistic effects of resistance training and dietary protein supplements. We hypothesized that a 25.1 g protein complex supplement taken for 12 weeks, immediately before and after resistance exercise, would enhance fat free mass and isokinetic muscular function in young untrained males.

Methods: Eighteen participants were randomly assigned to a placebo (n=8) or protein complex supplement groups (n=10). The RET was a supervised progressive program, 3 times per week for 12-weeks, and was performed progressing 80% of their one repetition maximum (1-RM). Body composition, blood pressure, plasma inflammatory markers, lipid level and isokinetic muscular function were assessed before and after the study period.

Results: There was a significant interaction effect in C-reactive protein (CRP) (p =0.044) among blood vessel inflammatory markers. The protein complex supplement group had shown more effective improvement at 12 weeks intervention compared to the placebo group in isokinetic muscular function. There was a significant interaction effect in peak torque at 60 degrees/sec leg extension (p =0.044), total work at 240 degrees/sec leg extension (p =0.025), and total work at 240 degrees/sec leg flexion (p =0.011).

Conclusion: Protein complex supplementation during RET appears more effective than RET alone in improving isokinetic muscular function for 12 weeks in untrained young men.
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http://dx.doi.org/10.20463/jenb.2017.0036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5772071PMC
December 2017
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