Chad Kerksick - Academia.edu (original) (raw)

Papers by Chad Kerksick

The Journal of Strength and Conditioning Research, 2004

R. Kreider. Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling... more R. Kreider. Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance. J. Strength Cond. Res. 18(3):466-472. 2004.-We examined the effect of low and high glycemic index (GI) carbohydrate (CHO) feedings during a simulated 64-km cycling time trial (TT) in nine subjects ([mean Ϯ SEM], age ϭ 30 Ϯ 1 years; weight ϭ 77.0 Ϯ 2.6 kg). Each rider completed three randomized, double blind, counterbalanced, crossover rides, where riders ingested 15 g of low GI (honey; GI ϭ 35) and high GI (dextrose; GI ϭ 100) CHO every 16 km. Our results showed no differences between groups for the time to complete the entire TT (honey ϭ 128 minutes, 42 seconds Ϯ 3.6 minutes; dextrose ϭ 128 minutes, 18 seconds Ϯ 3.8 minutes; placebo ϭ 131 minutes, 18 seconds Ϯ 3.9 minutes). However, an analysis of total time alone may not portray an accurate picture of TT performance under CHO-supplemented conditions. For example, when the CHO data were collapsed, the CHO condition (128 minutes, 30 seconds) proved faster than placebo condition (131 minutes, 18 seconds; p Ͻ 0.02). Furthermore, examining the percent differences and 95% confidence intervals (CI) shows the two CHO conditions to be generally faster, as the majority of the CI lies in the positive range: placebo vs. dextrose (2.36% [95% CI; Ϫ0.69, 4.64]) and honey (1.98% [95% CI; Ϫ0.30, 5.02]). Dextrose vs. honey was 0.39% (95% CI; Ϫ3.39, 4.15). Within treatment analysis also showed that subjects generated more watts (W) over the last 16 km vs. preceding segments for dextrose (p Ͻ 0.002) and honey (p Ͻ 0.0004) treatments. When the final 16-km W was expressed as a percentage of pretest maximal W, the dextrose treatment was greater than placebo (p Ͻ 0.05). A strong trend was noted for the honey condition (p Ͻ 0.06), despite no differences in heart rate (HR) or rate of perceived exertion (RPE). Our results show a trend for improvement in time and wattage over the last 16 km of a 64-km simulated TT regardless of glycemic index.

Probiotics and Antimicrobial Proteins

Weizmannia coagulans GBI-30, 6086 (BC30) has previously been shown to increase protein digestion ... more Weizmannia coagulans GBI-30, 6086 (BC30) has previously been shown to increase protein digestion in an in vitro model of the stomach and small intestine and amino acid appearance in healthy men and women after ingestion of milk protein concentrate. The impact of ingesting BC30 with other protein sources or in other demographics is largely unknown. The purpose of this study was to examine the impact of adding BC30 to a 20-g dose of a blend of rice and pea protein on postprandial changes in blood amino acids concentrations in healthy, older women. Healthy, older females (n = 30, 58.5 ± 5.2 years, 165.4 ± 6.8 cm, 65.6 ± 8.8 kg, 23.7 ± 3.2 kg/m2) completed two separate 14-day supplementation protocols separated by a 3-week washout period. Participants were instructed to ingest a 20-g protein dose of a blend of rice and pea protein concentrates (ProDiem Plant Protein Solutions, Kerry) with (PPCBC30) or without (PPC) the addition of 1 × 109 CFU BC30 (Kerry). Body composition and demograph...

Nutrients, 2022

Relative Energy Deficiency in sport is experiencing remarkable popularity of late, particularly a... more Relative Energy Deficiency in sport is experiencing remarkable popularity of late, particularly among female athletes. This condition is underpinned by low energy availability, which is a byproduct of high energy expenditure, inadequate energy intake, or a combination of the two. Several contributing factors exist that may predispose an athlete to low energy availability, and therefore a holistic and comprehensive assessment may be required to identify the root causes. The focus of the current narrative review is to discuss the primary contributing factors as well as known risk factors for low energy availability among female athletes to help practitioners increase awareness on the topic and identify future areas of focus.

Nutrients, 2019

Milk and dairy products are known to contain various bioactives with potential anti-inflammatory ... more Milk and dairy products are known to contain various bioactives with potential anti-inflammatory and immune modulating effects. Previous research has indicated that milk produced from hyperimmunized cows provided meaningful health benefits to individuals suffering from varying degrees of osteoarthritis and rheumatoid arthritis. PURPOSE: To examine the impact of MicroLactin®, a proprietary milk protein concentrate, on joint discomfort and physical function, exercise performance, quality of life and various measures of affect. METHODS: Non-osteoarthritic men (42.5 ± 8.9 years, 176.7 ± 6.7 cm, 89.9 ± 11.5 kg, 28.8 ± 3.5 kg/m2, n = 30) and women (46.4 ± 9.6 years, 163.1 ± 8.2 cm, 72.2 ± 13.1 kg, 27.2 ± 5.3 kg/m2, n = 28) with mild to moderate knee pain during physical activity were randomized in a double-blind, placebo-controlled fashion to consume daily either a placebo (PLA) or MicroLactin® (ML) for a period of 8 weeks. Participants completed a functional capacity test pre and post-su...

Nutrients, 2021

Creatine (Cr) and phosphocreatine (PCr) are physiologically essential molecules for life, given t... more Creatine (Cr) and phosphocreatine (PCr) are physiologically essential molecules for life, given they serve as rapid and localized support of energy- and mechanical-dependent processes. This evolutionary advantage is based on the action of creatine kinase (CK) isozymes that connect places of ATP synthesis with sites of ATP consumption (the CK/PCr system). Supplementation with creatine monohydrate (CrM) can enhance this system, resulting in well-known ergogenic effects and potential health or therapeutic benefits. In spite of our vast knowledge about these molecules, no integrative analysis of molecular mechanisms under a systems biology approach has been performed to date; thus, we aimed to perform for the first time a convergent functional genomics analysis to identify biological regulators mediating the effects of Cr supplementation in health and disease. A total of 35 differentially expressed genes were analyzed. We identified top-ranked pathways and biological processes mediating...

Nutrients, 2021

Sport nutrition knowledge has been shown to influence dietary habits of athletes. The purpose of ... more Sport nutrition knowledge has been shown to influence dietary habits of athletes. The purpose of the current study was to examine relationships between sport nutrition knowledge and body composition and examine potential predictors of body weight goals in collegiate athletes. Participants included National Collegiate Athletic Association Division III women (n = 42, height: 169.9 ± 6.9 cm; body mass: 67.1 ± 8.6 kg; fat-free mass: 51.3 ± 6.6 kg; body fat percent: 24.2 ± 5.3%) and men (n = 25, height: 180.8 ± 7.2 cm; body mass: 89.2 ± 20.5 kg; fat-free mass: 75.9 ± 12.2 kg; body fat percent: 13.5 ± 8.9%) athletes. Body composition was assessed via air displacement plethysmography. Athletes completed a validated questionnaire designed to assess sport nutrition knowledge and were asked questions about their perceived dietary energy and macronutrient requirements, as well as their body weight goal (i.e., lose, maintain, gain weight). Athletes answered 47.98 ± 11.29% of questions correctly...

The FASEB Journal, 2007

The consumption of diets with increasing caloric intakes after acute hypo-energetic dieting on se... more The consumption of diets with increasing caloric intakes after acute hypo-energetic dieting on serum weight management markers were examined. Sedentary, obese women (n=122) for 7d consumed either their normal diet (CON, n=14), a higher carbohydrate (%CHO: PRO: FAT= 46: 24: 30; n=52) or higher protein (%CHO: PRO: FAT= 24: 46: 30; n=56) hypocaloric (HYPO) diet (1,000 kcal•d-1). Subjects then consumed for 7d either 1,600 (n=27), 2,100 (n=26), 2,600 (n=30), or 3,100 (n=25) kcal•d-1 consisting of (%CHO: PRO: FAT= 55: 15: 30) while CON maintained their normal diet. After 7 and 14d of dieting, participants provided fasting blood samples for determination of body mass, serum insulin, leptin, adiponectin and ghrelin levels. Data were analyzed by Pearson correlations and repeated measures ANOVA using an alpha level of 0.05. Adiponectin levels did not change (p<0.05) and no changes were reported relative to macronutrient intake through the first week of dieting. Significant but equal weight loss occurred in both HYPO groups, while leptin increased and insulin decreased in all groups. Ghrelin and leptin levels increased in all groups after increasing caloric intake. A significant interaction effect was found for leptin, with the 3,100 calories and CON group reporting higher levels of leptin in comparison to all other diet groups. Ghrelin in all groups was greater after dieting in comparison to baseline. Leptin was correlated to changes in body mass (r=0.409; p<0.01) and insulin (r=0.369;p<0.01). Initial HYPO dieting decreased body mass, insulin and leptin levels while adiponectin was unchanged. Increased caloric intake increased leptin levels in conjunction with caloric intake.

Nutrients, 2020

Vitamin D and calcium supplementation have been posited to improve body composition and different... more Vitamin D and calcium supplementation have been posited to improve body composition and different formulations of calcium may impact bioavailability. However, data are lacking regarding the combinatorial effects of exercise, diet, and calcium and/or vitamin D supplementation on body composition changes in post-menopausal women. Herein, 128 post-menopausal women (51.3 ± 4.5 years, 36.4 ± 5.7 kg/m2, 46.2 ± 4.5% fat) were assigned to diet and supplement groups while participating in a supervised circuit-style resistance-training program (3 d/week) over a 14-week period. Diet groups included: (1) normal diet (CTL), (2) a low-calorie, higher protein diet (LCHP; 1600 kcal/day, 15% carbohydrates, 55% protein, 30% fat), and (3) a low-calorie, higher carbohydrate diet (LCHC; 1600 kcal/day, 55% carbohydrates, 15% protein, 30% fat). Supplement groups consisted of: (1) maltodextrin (PLA), (2) 800 mg/day of calcium carbonate (Ca), and (3) 800 mg/day of calcium citrate and malate and 400 IU/day o...

Nutrients, 2019

Little data is available regarding the energy and nutritional status of female collegiate team sp... more Little data is available regarding the energy and nutritional status of female collegiate team sport athletes. Twenty female NCAA Division II lacrosse athletes (mean ± SD: 20.4 ± 1.8 years; 68.8 ± 8.9 kg; 168.4 ± 6.6 cm; 27.9 ± 3% body fat) recorded dietary intake and wore a physical activity monitor over four consecutive days at five different time points (20 days total) during one academic year. Body composition, bone health, and resting metabolic rate were assessed in conjunction with wearing the monitor during off-season, pre-season, and season-play. Body fat percentage decreased slightly during the course of this study (p = 0.037). Total daily energy expenditure (TDEE) (p < 0.001) and activity energy expenditure (AEE) (p = 0.001) energy were found to change significantly over the course of the year, with pre-season training resulting in the highest energy expenditures (TDEE: 2789 ± 391 kcal/day; AEE: 1001 ± 267 kcal/day). Caloric (2124 ± 448 kcal/day), carbohydrate (3.6 ± 1....

International Journal of Sport Nutrition and Exercise Metabolism, 2005

This study examined whether ribose supplementation before and during intense anaerobic exercise i... more This study examined whether ribose supplementation before and during intense anaerobic exercise impacts anaerobic capacity and metabolic markers. Twelve moderately trained male cyclists (22.3 ± 2.2 y; 181 ± 6 cm, 74.8 ± 9 kg) participated in the study. Subjects were familiarized and fasted for 8 h after standardizing nutritional intake. In a double blind and crossover manner subjects ingested either a 150 mL placebo or ribose (3 g ribose + 150 μg folate). Subjects rested for 25 min and completed 5 × 30 s anaerobic capacity tests with 3 min passive rest. Six capillary blood samples were taken prior to and after sprints for adenine nucleotide breakdown determination. The experiment was repeated 1 wk later with alternative drink. Data were analyzed by repeated measures ANOVA. No significant interactions were observed for any performance or blood variables. D-ribose supplementation has no impact on anaerobic exercise capacity and metabolic markers after high-intensity cycling exercise.

International Journal of Sport Nutrition and Exercise Metabolism, 2010

Background:This investigation examined the safety and efficacy of a silica-based mineral antioxid... more Background:This investigation examined the safety and efficacy of a silica-based mineral antioxidant complex (MAC) that has been suggested to influence body water and buffer lactate.Methods:In a double-blind, randomized crossover design, male participants completed testing for 3 conditions: water only (baseline), rice flour (placebo), and MAC supplementation. Participants visited the laboratory on 5 occasions: familiarization, baseline, Testing Day 1, washout, and Testing Day 2. Baseline and Testing Days 1 and 2 consisted of fasting blood, pre- to postexercise body-water assessment and determination of VO2peak on a cycle ergometer. The supplementation protocols were separated by 1 wk and balanced to minimize an order effect.Results:No differences between conditions were found for heart rate, blood pressure, or serum-safety markers (p > .05). Before exercise there were no differences between conditions for total body water (TBW), intracellular water (ICW), or extracellular water (...

Journal of the International Society of Sports Nutrition, 2015

Limited research exists examining the impact of nutrition on golfing performance. This study'... more Limited research exists examining the impact of nutrition on golfing performance. This study's purpose was to determine the impact of daily supplementation with an over-the-counter dietary supplement on golf performance. Healthy men (30.3 ± 6.9 y, 183.1 ± 5.6 cm, 86.7 ± 11.9 kg), with a 5-15 handicap were assigned in a double-blind, placebo-controlled manner to ingest for 30 days either a placebo (PLA, n = 13) or a dietary supplement containing creatine monohydrate, coffea arabica fruit extract, calcium fructoborate and vitamin D (Strong Drive™, SD, n = 14). Subjects ingested two daily doses for the first two weeks and one daily dose for the remaining two weeks. Participants followed their normal dietary habits and did not change their physical activity patterns. Two identical testing sessions in a pre/post fashion were completed consisting of a fasting blood sample, anthropometric measurements, 1-RM bench press, upper body power and golf swing performance using their driver and...

Dynamic medicine : DM, Jan 24, 2009

Creatine supplementation has been found to significantly increase muscle strength and hypertrophy... more Creatine supplementation has been found to significantly increase muscle strength and hypertrophy in young adults (</= 35 yr) particularly when consumed in conjunction with a resistance training regime. Literature examining the efficacy of creatine supplementation in older adults (55-82 yr) suggests creatine to promote muscle strength and hypertrophy to a greater extent than resistance training alone. The following is a review of literature reporting on the effects of creatine supplementation on intramuscular high energy phosphates, skeletal muscle morphology and quality of life in older adults. Results suggest creatine supplementation to be a safe, inexpensive and effective nutritional intervention, particularly when consumed in conjunction with a resistance training regime, for slowing the rate of muscle wasting that is associated with aging. Physicians should strongly consider advising older adults to supplement with creatine and to begin a resistance training regime in an eff...

Strength and Conditioning Journal, 2010

Nutrition Journal, 2010

Background This study's purpose investigated the impact of different macronutrient distributi... more Background This study's purpose investigated the impact of different macronutrient distributions and varying caloric intakes along with regular exercise for metabolic and physiological changes related to weight loss. Methods One hundred forty-one sedentary, obese women (38.7 ± 8.0 yrs, 163.3 ± 6.9 cm, 93.2 ± 16.5 kg, 35.0 ± 6.2 kg•m-2, 44.8 ± 4.2% fat) were randomized to either no diet + no exercise control group (CON) a no diet + exercise control (ND), or one of four diet + exercise groups (high-energy diet [HED], very low carbohydrate, high protein diet [VLCHP], low carbohydrate, moderate protein diet [LCMP] and high carbohydrate, low protein [HCLP]) in addition to beginning a 3x•week-1 supervised resistance training program. After 0, 1, 10 and 14 weeks, all participants completed testing sessions which included anthropometric, body composition, energy expenditure, fasting blood samples, aerobic and muscular fitness assessments. Data were analyzed using repeated measures ANOVA...

Nutrition & Metabolism, 2009

Objective To determine the safety and efficacy of altering the ratio of carbohydrate and protein ... more Objective To determine the safety and efficacy of altering the ratio of carbohydrate and protein in low-energy diets in conjunction with a popular exercise program in obese women. Design Matched, prospective clinical intervention study to assess efficacy of varying ratios of carbohydrate and protein intake in conjunction with a regular exercise program. Participants One-hundred sixty one sedentary, obese, pre-menopausal women (38.5 ± 8.5 yrs, 164.2 ± 6.7 cm, 94.2 ± 18.8 kg, 34.9 ± 6.4 kg·m-2, 43.8 ± 4.2%) participated in this study. Participants were weight stable and not participating in additional weight loss programs. Methods Participants were assigned to either a no exercise + no diet control (CON), a no diet + exercise group (ND), or one of four diet + exercise groups (presented as kcals; % carbohydrate: protein: fat): 1) a high energy, high carbohydrate, low protein diet (HED) [2,600; 55:15:30%], 2) a very low carbohydrate, high protein diet (VLCHP) [1,200 kcals; 63:7:30%], 3)...

Nutrition, 2011

Objective: We examined whether the ingestion of a hydrothermally modified starch (HMS) would alte... more Objective: We examined whether the ingestion of a hydrothermally modified starch (HMS) would alter metabolic and hormonal responses to prolonged cycling compared with maltodextrin (MAL). Methods: Nine male cyclists (30 AE 2 y, 79.2 AE 2.1 kg, 4.7 AE 0.1 L of O 2 /min, 7.5 AE 1.3 y training) fasted 10 h before cycling for 150 min at 70% peak oxygen consumption and completing a cyclingto-exhaustion trial at 100% peak oxygen consumption. Participants ingested 1g/kg of HMS or MAL 30 min before and within 10 min of completing the bout. Blood samples were provided every 15 min before, during, and 90 min after exercise. Expired gases were collected every 30 min during exercise. In a crossover, randomized, and double-blind fashion, identical testing was completed 1 wk later. Results: Primary findings from this study were that 1) increases in serum glucose were greater during MAL (peak 9.5 mM) versus HMS (peak 7.4 mM, P 0.01), 2) insulin levels were significantly lower during HMS (peak 2.5 mIU/mL) versus MAL (peak 20.3 mIU/mL, P < 0.001), and 3) HMS was associated with greater fat breakdown as indicated by the increased serum non-esterified fatty acids (P < 0.01) and glycerol levels (P < 0.05). Conclusion: Ingestion of a low-glycemic HMS before prolonged cycling exercise blunted the initial spike in serum glucose and insulin and increased the breakdown in fat compared with MAL.

Journal of the International Society of Sports Nutrition, 2004

This study examined whether supplementing the diet with a commercial supplement containing zinc m... more This study examined whether supplementing the diet with a commercial supplement containing zinc magnesium aspartate (ZMA) during training affects zinc and magnesium status, anabolic and catabolic hormone profiles, and/or training adaptations. Forty-two resistance trained males (27±9 yrs; 178±8 cm, 85±15 kg, 18.6±6% body fat) were matched according to fat free mass and randomly assigned to ingest in a double blind manner either a dextrose placebo (P) or ZMA 30-60 minutes prior to going to sleep during 8-weeks of standardized resistance-training. Subjects completed testing sessions at 0, 4, and 8 weeks that included body composition assessment as determined by dual energy X-ray absorptiometry, 1-RM and muscular endurance tests on the bench and leg press, a Wingate anaerobic power test, and blood analysis to assess anabolic/catabolic status as well as markers of health. Data were analyzed using repeated measures ANOVA. Results indicated that ZMA supplementation non-significantly increased serum zinc levels by 11-17% (p=0.12). However, no significant differences were observed between groups in anabolic or catabolic hormone status, body composition, 1-RM bench press and leg press, upper or lower body muscular endurance, or cycling anaerobic capacity. Results indicate that ZMA supplementation during training does not appear to enhance training adaptations in resistance trained populations.

Journal of the International Society of Sports Nutrition, 2011

Background The purpose of this study was to determine whether sedentary obese women with knee OA ... more Background The purpose of this study was to determine whether sedentary obese women with knee OA initiating an exercise and weight loss program may experience more beneficial changes in body composition, functional capacity, and/or markers of health following a higher protein diet compared to a higher carbohydrate diet with or without GCM supplementation. Methods Thirty sedentary women (54 ± 9 yrs, 163 ± 6 cm, 88.6 ± 13 kg, 46.1 ± 3% fat, 33.3 ± 5 kg/m2) with clinically diagnosed knee OA participated in a 14-week exercise and weight loss program. Participants followed an isoenergenic low fat higher carbohydrate (HC) or higher protein (HP) diet while participating in a supervised 30-minute circuit resistance-training program three times per week for 14-weeks. In a randomized and double blind manner, participants ingested supplements containing 1,500 mg/d of glucosamine (as d-glucosamine HCL), 1,200 mg/d of chondroitin sulfate (from chondroitin sulfate sodium), and 900 mg/d of methyls...

Journal of the International Society of Sports Nutrition, 2008

Background To determine whether acute (single dose) and/or chronic (14-days) supplementation of C... more Background To determine whether acute (single dose) and/or chronic (14-days) supplementation of CoQ10 will improve anaerobic and/or aerobic exercise performance by increasing plasma and muscle CoQ10 concentrations within trained and untrained individuals. Methods Twenty-two aerobically trained and nineteen untrained male and female subjects (26.1 ± 7.6 yrs, 172 ± 8.7 cm, 73.5 ± 17 kg, and 21.2 ± 7.0%) were randomized to ingest in a double-blind manner either 100 mg of a dextrose placebo (CON) or a fast-melt CoQ10 supplement (CoQ10) twice a day for 14-days. On the first day of supplementation, subjects donated fasting blood samples and a muscle biopsy. Subjects were then given 200 mg of the placebo or the CoQ10 supplement. Sixty minutes following supplement ingestion, subjects completed an isokinetic knee extension endurance test, a 30-second wingate anaerobic capacity test, and a maximal cardiopulmonary graded exercise test interspersed with 30-minutes of recovery. Additional blood ...

The Journal of Strength and Conditioning Research, 2004

R. Kreider. Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling... more R. Kreider. Low vs. high glycemic index carbohydrate gel ingestion during simulated 64-km cycling time trial performance. J. Strength Cond. Res. 18(3):466-472. 2004.-We examined the effect of low and high glycemic index (GI) carbohydrate (CHO) feedings during a simulated 64-km cycling time trial (TT) in nine subjects ([mean Ϯ SEM], age ϭ 30 Ϯ 1 years; weight ϭ 77.0 Ϯ 2.6 kg). Each rider completed three randomized, double blind, counterbalanced, crossover rides, where riders ingested 15 g of low GI (honey; GI ϭ 35) and high GI (dextrose; GI ϭ 100) CHO every 16 km. Our results showed no differences between groups for the time to complete the entire TT (honey ϭ 128 minutes, 42 seconds Ϯ 3.6 minutes; dextrose ϭ 128 minutes, 18 seconds Ϯ 3.8 minutes; placebo ϭ 131 minutes, 18 seconds Ϯ 3.9 minutes). However, an analysis of total time alone may not portray an accurate picture of TT performance under CHO-supplemented conditions. For example, when the CHO data were collapsed, the CHO condition (128 minutes, 30 seconds) proved faster than placebo condition (131 minutes, 18 seconds; p Ͻ 0.02). Furthermore, examining the percent differences and 95% confidence intervals (CI) shows the two CHO conditions to be generally faster, as the majority of the CI lies in the positive range: placebo vs. dextrose (2.36% [95% CI; Ϫ0.69, 4.64]) and honey (1.98% [95% CI; Ϫ0.30, 5.02]). Dextrose vs. honey was 0.39% (95% CI; Ϫ3.39, 4.15). Within treatment analysis also showed that subjects generated more watts (W) over the last 16 km vs. preceding segments for dextrose (p Ͻ 0.002) and honey (p Ͻ 0.0004) treatments. When the final 16-km W was expressed as a percentage of pretest maximal W, the dextrose treatment was greater than placebo (p Ͻ 0.05). A strong trend was noted for the honey condition (p Ͻ 0.06), despite no differences in heart rate (HR) or rate of perceived exertion (RPE). Our results show a trend for improvement in time and wattage over the last 16 km of a 64-km simulated TT regardless of glycemic index.

Probiotics and Antimicrobial Proteins

Weizmannia coagulans GBI-30, 6086 (BC30) has previously been shown to increase protein digestion ... more Weizmannia coagulans GBI-30, 6086 (BC30) has previously been shown to increase protein digestion in an in vitro model of the stomach and small intestine and amino acid appearance in healthy men and women after ingestion of milk protein concentrate. The impact of ingesting BC30 with other protein sources or in other demographics is largely unknown. The purpose of this study was to examine the impact of adding BC30 to a 20-g dose of a blend of rice and pea protein on postprandial changes in blood amino acids concentrations in healthy, older women. Healthy, older females (n = 30, 58.5 ± 5.2 years, 165.4 ± 6.8 cm, 65.6 ± 8.8 kg, 23.7 ± 3.2 kg/m2) completed two separate 14-day supplementation protocols separated by a 3-week washout period. Participants were instructed to ingest a 20-g protein dose of a blend of rice and pea protein concentrates (ProDiem Plant Protein Solutions, Kerry) with (PPCBC30) or without (PPC) the addition of 1 × 109 CFU BC30 (Kerry). Body composition and demograph...

Nutrients, 2022

Relative Energy Deficiency in sport is experiencing remarkable popularity of late, particularly a... more Relative Energy Deficiency in sport is experiencing remarkable popularity of late, particularly among female athletes. This condition is underpinned by low energy availability, which is a byproduct of high energy expenditure, inadequate energy intake, or a combination of the two. Several contributing factors exist that may predispose an athlete to low energy availability, and therefore a holistic and comprehensive assessment may be required to identify the root causes. The focus of the current narrative review is to discuss the primary contributing factors as well as known risk factors for low energy availability among female athletes to help practitioners increase awareness on the topic and identify future areas of focus.

Nutrients, 2019

Milk and dairy products are known to contain various bioactives with potential anti-inflammatory ... more Milk and dairy products are known to contain various bioactives with potential anti-inflammatory and immune modulating effects. Previous research has indicated that milk produced from hyperimmunized cows provided meaningful health benefits to individuals suffering from varying degrees of osteoarthritis and rheumatoid arthritis. PURPOSE: To examine the impact of MicroLactin®, a proprietary milk protein concentrate, on joint discomfort and physical function, exercise performance, quality of life and various measures of affect. METHODS: Non-osteoarthritic men (42.5 ± 8.9 years, 176.7 ± 6.7 cm, 89.9 ± 11.5 kg, 28.8 ± 3.5 kg/m2, n = 30) and women (46.4 ± 9.6 years, 163.1 ± 8.2 cm, 72.2 ± 13.1 kg, 27.2 ± 5.3 kg/m2, n = 28) with mild to moderate knee pain during physical activity were randomized in a double-blind, placebo-controlled fashion to consume daily either a placebo (PLA) or MicroLactin® (ML) for a period of 8 weeks. Participants completed a functional capacity test pre and post-su...

Nutrients, 2021

Creatine (Cr) and phosphocreatine (PCr) are physiologically essential molecules for life, given t... more Creatine (Cr) and phosphocreatine (PCr) are physiologically essential molecules for life, given they serve as rapid and localized support of energy- and mechanical-dependent processes. This evolutionary advantage is based on the action of creatine kinase (CK) isozymes that connect places of ATP synthesis with sites of ATP consumption (the CK/PCr system). Supplementation with creatine monohydrate (CrM) can enhance this system, resulting in well-known ergogenic effects and potential health or therapeutic benefits. In spite of our vast knowledge about these molecules, no integrative analysis of molecular mechanisms under a systems biology approach has been performed to date; thus, we aimed to perform for the first time a convergent functional genomics analysis to identify biological regulators mediating the effects of Cr supplementation in health and disease. A total of 35 differentially expressed genes were analyzed. We identified top-ranked pathways and biological processes mediating...

Nutrients, 2021

Sport nutrition knowledge has been shown to influence dietary habits of athletes. The purpose of ... more Sport nutrition knowledge has been shown to influence dietary habits of athletes. The purpose of the current study was to examine relationships between sport nutrition knowledge and body composition and examine potential predictors of body weight goals in collegiate athletes. Participants included National Collegiate Athletic Association Division III women (n = 42, height: 169.9 ± 6.9 cm; body mass: 67.1 ± 8.6 kg; fat-free mass: 51.3 ± 6.6 kg; body fat percent: 24.2 ± 5.3%) and men (n = 25, height: 180.8 ± 7.2 cm; body mass: 89.2 ± 20.5 kg; fat-free mass: 75.9 ± 12.2 kg; body fat percent: 13.5 ± 8.9%) athletes. Body composition was assessed via air displacement plethysmography. Athletes completed a validated questionnaire designed to assess sport nutrition knowledge and were asked questions about their perceived dietary energy and macronutrient requirements, as well as their body weight goal (i.e., lose, maintain, gain weight). Athletes answered 47.98 ± 11.29% of questions correctly...

The FASEB Journal, 2007

The consumption of diets with increasing caloric intakes after acute hypo-energetic dieting on se... more The consumption of diets with increasing caloric intakes after acute hypo-energetic dieting on serum weight management markers were examined. Sedentary, obese women (n=122) for 7d consumed either their normal diet (CON, n=14), a higher carbohydrate (%CHO: PRO: FAT= 46: 24: 30; n=52) or higher protein (%CHO: PRO: FAT= 24: 46: 30; n=56) hypocaloric (HYPO) diet (1,000 kcal•d-1). Subjects then consumed for 7d either 1,600 (n=27), 2,100 (n=26), 2,600 (n=30), or 3,100 (n=25) kcal•d-1 consisting of (%CHO: PRO: FAT= 55: 15: 30) while CON maintained their normal diet. After 7 and 14d of dieting, participants provided fasting blood samples for determination of body mass, serum insulin, leptin, adiponectin and ghrelin levels. Data were analyzed by Pearson correlations and repeated measures ANOVA using an alpha level of 0.05. Adiponectin levels did not change (p<0.05) and no changes were reported relative to macronutrient intake through the first week of dieting. Significant but equal weight loss occurred in both HYPO groups, while leptin increased and insulin decreased in all groups. Ghrelin and leptin levels increased in all groups after increasing caloric intake. A significant interaction effect was found for leptin, with the 3,100 calories and CON group reporting higher levels of leptin in comparison to all other diet groups. Ghrelin in all groups was greater after dieting in comparison to baseline. Leptin was correlated to changes in body mass (r=0.409; p<0.01) and insulin (r=0.369;p<0.01). Initial HYPO dieting decreased body mass, insulin and leptin levels while adiponectin was unchanged. Increased caloric intake increased leptin levels in conjunction with caloric intake.

Nutrients, 2020

Vitamin D and calcium supplementation have been posited to improve body composition and different... more Vitamin D and calcium supplementation have been posited to improve body composition and different formulations of calcium may impact bioavailability. However, data are lacking regarding the combinatorial effects of exercise, diet, and calcium and/or vitamin D supplementation on body composition changes in post-menopausal women. Herein, 128 post-menopausal women (51.3 ± 4.5 years, 36.4 ± 5.7 kg/m2, 46.2 ± 4.5% fat) were assigned to diet and supplement groups while participating in a supervised circuit-style resistance-training program (3 d/week) over a 14-week period. Diet groups included: (1) normal diet (CTL), (2) a low-calorie, higher protein diet (LCHP; 1600 kcal/day, 15% carbohydrates, 55% protein, 30% fat), and (3) a low-calorie, higher carbohydrate diet (LCHC; 1600 kcal/day, 55% carbohydrates, 15% protein, 30% fat). Supplement groups consisted of: (1) maltodextrin (PLA), (2) 800 mg/day of calcium carbonate (Ca), and (3) 800 mg/day of calcium citrate and malate and 400 IU/day o...

Nutrients, 2019

Little data is available regarding the energy and nutritional status of female collegiate team sp... more Little data is available regarding the energy and nutritional status of female collegiate team sport athletes. Twenty female NCAA Division II lacrosse athletes (mean ± SD: 20.4 ± 1.8 years; 68.8 ± 8.9 kg; 168.4 ± 6.6 cm; 27.9 ± 3% body fat) recorded dietary intake and wore a physical activity monitor over four consecutive days at five different time points (20 days total) during one academic year. Body composition, bone health, and resting metabolic rate were assessed in conjunction with wearing the monitor during off-season, pre-season, and season-play. Body fat percentage decreased slightly during the course of this study (p = 0.037). Total daily energy expenditure (TDEE) (p < 0.001) and activity energy expenditure (AEE) (p = 0.001) energy were found to change significantly over the course of the year, with pre-season training resulting in the highest energy expenditures (TDEE: 2789 ± 391 kcal/day; AEE: 1001 ± 267 kcal/day). Caloric (2124 ± 448 kcal/day), carbohydrate (3.6 ± 1....

International Journal of Sport Nutrition and Exercise Metabolism, 2005

This study examined whether ribose supplementation before and during intense anaerobic exercise i... more This study examined whether ribose supplementation before and during intense anaerobic exercise impacts anaerobic capacity and metabolic markers. Twelve moderately trained male cyclists (22.3 ± 2.2 y; 181 ± 6 cm, 74.8 ± 9 kg) participated in the study. Subjects were familiarized and fasted for 8 h after standardizing nutritional intake. In a double blind and crossover manner subjects ingested either a 150 mL placebo or ribose (3 g ribose + 150 μg folate). Subjects rested for 25 min and completed 5 × 30 s anaerobic capacity tests with 3 min passive rest. Six capillary blood samples were taken prior to and after sprints for adenine nucleotide breakdown determination. The experiment was repeated 1 wk later with alternative drink. Data were analyzed by repeated measures ANOVA. No significant interactions were observed for any performance or blood variables. D-ribose supplementation has no impact on anaerobic exercise capacity and metabolic markers after high-intensity cycling exercise.

International Journal of Sport Nutrition and Exercise Metabolism, 2010

Background:This investigation examined the safety and efficacy of a silica-based mineral antioxid... more Background:This investigation examined the safety and efficacy of a silica-based mineral antioxidant complex (MAC) that has been suggested to influence body water and buffer lactate.Methods:In a double-blind, randomized crossover design, male participants completed testing for 3 conditions: water only (baseline), rice flour (placebo), and MAC supplementation. Participants visited the laboratory on 5 occasions: familiarization, baseline, Testing Day 1, washout, and Testing Day 2. Baseline and Testing Days 1 and 2 consisted of fasting blood, pre- to postexercise body-water assessment and determination of VO2peak on a cycle ergometer. The supplementation protocols were separated by 1 wk and balanced to minimize an order effect.Results:No differences between conditions were found for heart rate, blood pressure, or serum-safety markers (p > .05). Before exercise there were no differences between conditions for total body water (TBW), intracellular water (ICW), or extracellular water (...

Journal of the International Society of Sports Nutrition, 2015

Limited research exists examining the impact of nutrition on golfing performance. This study'... more Limited research exists examining the impact of nutrition on golfing performance. This study's purpose was to determine the impact of daily supplementation with an over-the-counter dietary supplement on golf performance. Healthy men (30.3 ± 6.9 y, 183.1 ± 5.6 cm, 86.7 ± 11.9 kg), with a 5-15 handicap were assigned in a double-blind, placebo-controlled manner to ingest for 30 days either a placebo (PLA, n = 13) or a dietary supplement containing creatine monohydrate, coffea arabica fruit extract, calcium fructoborate and vitamin D (Strong Drive™, SD, n = 14). Subjects ingested two daily doses for the first two weeks and one daily dose for the remaining two weeks. Participants followed their normal dietary habits and did not change their physical activity patterns. Two identical testing sessions in a pre/post fashion were completed consisting of a fasting blood sample, anthropometric measurements, 1-RM bench press, upper body power and golf swing performance using their driver and...

Dynamic medicine : DM, Jan 24, 2009

Creatine supplementation has been found to significantly increase muscle strength and hypertrophy... more Creatine supplementation has been found to significantly increase muscle strength and hypertrophy in young adults (</= 35 yr) particularly when consumed in conjunction with a resistance training regime. Literature examining the efficacy of creatine supplementation in older adults (55-82 yr) suggests creatine to promote muscle strength and hypertrophy to a greater extent than resistance training alone. The following is a review of literature reporting on the effects of creatine supplementation on intramuscular high energy phosphates, skeletal muscle morphology and quality of life in older adults. Results suggest creatine supplementation to be a safe, inexpensive and effective nutritional intervention, particularly when consumed in conjunction with a resistance training regime, for slowing the rate of muscle wasting that is associated with aging. Physicians should strongly consider advising older adults to supplement with creatine and to begin a resistance training regime in an eff...

Strength and Conditioning Journal, 2010

Nutrition Journal, 2010

Background This study's purpose investigated the impact of different macronutrient distributi... more Background This study's purpose investigated the impact of different macronutrient distributions and varying caloric intakes along with regular exercise for metabolic and physiological changes related to weight loss. Methods One hundred forty-one sedentary, obese women (38.7 ± 8.0 yrs, 163.3 ± 6.9 cm, 93.2 ± 16.5 kg, 35.0 ± 6.2 kg•m-2, 44.8 ± 4.2% fat) were randomized to either no diet + no exercise control group (CON) a no diet + exercise control (ND), or one of four diet + exercise groups (high-energy diet [HED], very low carbohydrate, high protein diet [VLCHP], low carbohydrate, moderate protein diet [LCMP] and high carbohydrate, low protein [HCLP]) in addition to beginning a 3x•week-1 supervised resistance training program. After 0, 1, 10 and 14 weeks, all participants completed testing sessions which included anthropometric, body composition, energy expenditure, fasting blood samples, aerobic and muscular fitness assessments. Data were analyzed using repeated measures ANOVA...

Nutrition & Metabolism, 2009

Objective To determine the safety and efficacy of altering the ratio of carbohydrate and protein ... more Objective To determine the safety and efficacy of altering the ratio of carbohydrate and protein in low-energy diets in conjunction with a popular exercise program in obese women. Design Matched, prospective clinical intervention study to assess efficacy of varying ratios of carbohydrate and protein intake in conjunction with a regular exercise program. Participants One-hundred sixty one sedentary, obese, pre-menopausal women (38.5 ± 8.5 yrs, 164.2 ± 6.7 cm, 94.2 ± 18.8 kg, 34.9 ± 6.4 kg·m-2, 43.8 ± 4.2%) participated in this study. Participants were weight stable and not participating in additional weight loss programs. Methods Participants were assigned to either a no exercise + no diet control (CON), a no diet + exercise group (ND), or one of four diet + exercise groups (presented as kcals; % carbohydrate: protein: fat): 1) a high energy, high carbohydrate, low protein diet (HED) [2,600; 55:15:30%], 2) a very low carbohydrate, high protein diet (VLCHP) [1,200 kcals; 63:7:30%], 3)...

Nutrition, 2011

Objective: We examined whether the ingestion of a hydrothermally modified starch (HMS) would alte... more Objective: We examined whether the ingestion of a hydrothermally modified starch (HMS) would alter metabolic and hormonal responses to prolonged cycling compared with maltodextrin (MAL). Methods: Nine male cyclists (30 AE 2 y, 79.2 AE 2.1 kg, 4.7 AE 0.1 L of O 2 /min, 7.5 AE 1.3 y training) fasted 10 h before cycling for 150 min at 70% peak oxygen consumption and completing a cyclingto-exhaustion trial at 100% peak oxygen consumption. Participants ingested 1g/kg of HMS or MAL 30 min before and within 10 min of completing the bout. Blood samples were provided every 15 min before, during, and 90 min after exercise. Expired gases were collected every 30 min during exercise. In a crossover, randomized, and double-blind fashion, identical testing was completed 1 wk later. Results: Primary findings from this study were that 1) increases in serum glucose were greater during MAL (peak 9.5 mM) versus HMS (peak 7.4 mM, P 0.01), 2) insulin levels were significantly lower during HMS (peak 2.5 mIU/mL) versus MAL (peak 20.3 mIU/mL, P < 0.001), and 3) HMS was associated with greater fat breakdown as indicated by the increased serum non-esterified fatty acids (P < 0.01) and glycerol levels (P < 0.05). Conclusion: Ingestion of a low-glycemic HMS before prolonged cycling exercise blunted the initial spike in serum glucose and insulin and increased the breakdown in fat compared with MAL.

Journal of the International Society of Sports Nutrition, 2004

This study examined whether supplementing the diet with a commercial supplement containing zinc m... more This study examined whether supplementing the diet with a commercial supplement containing zinc magnesium aspartate (ZMA) during training affects zinc and magnesium status, anabolic and catabolic hormone profiles, and/or training adaptations. Forty-two resistance trained males (27±9 yrs; 178±8 cm, 85±15 kg, 18.6±6% body fat) were matched according to fat free mass and randomly assigned to ingest in a double blind manner either a dextrose placebo (P) or ZMA 30-60 minutes prior to going to sleep during 8-weeks of standardized resistance-training. Subjects completed testing sessions at 0, 4, and 8 weeks that included body composition assessment as determined by dual energy X-ray absorptiometry, 1-RM and muscular endurance tests on the bench and leg press, a Wingate anaerobic power test, and blood analysis to assess anabolic/catabolic status as well as markers of health. Data were analyzed using repeated measures ANOVA. Results indicated that ZMA supplementation non-significantly increased serum zinc levels by 11-17% (p=0.12). However, no significant differences were observed between groups in anabolic or catabolic hormone status, body composition, 1-RM bench press and leg press, upper or lower body muscular endurance, or cycling anaerobic capacity. Results indicate that ZMA supplementation during training does not appear to enhance training adaptations in resistance trained populations.

Journal of the International Society of Sports Nutrition, 2011

Background The purpose of this study was to determine whether sedentary obese women with knee OA ... more Background The purpose of this study was to determine whether sedentary obese women with knee OA initiating an exercise and weight loss program may experience more beneficial changes in body composition, functional capacity, and/or markers of health following a higher protein diet compared to a higher carbohydrate diet with or without GCM supplementation. Methods Thirty sedentary women (54 ± 9 yrs, 163 ± 6 cm, 88.6 ± 13 kg, 46.1 ± 3% fat, 33.3 ± 5 kg/m2) with clinically diagnosed knee OA participated in a 14-week exercise and weight loss program. Participants followed an isoenergenic low fat higher carbohydrate (HC) or higher protein (HP) diet while participating in a supervised 30-minute circuit resistance-training program three times per week for 14-weeks. In a randomized and double blind manner, participants ingested supplements containing 1,500 mg/d of glucosamine (as d-glucosamine HCL), 1,200 mg/d of chondroitin sulfate (from chondroitin sulfate sodium), and 900 mg/d of methyls...

Journal of the International Society of Sports Nutrition, 2008

Background To determine whether acute (single dose) and/or chronic (14-days) supplementation of C... more Background To determine whether acute (single dose) and/or chronic (14-days) supplementation of CoQ10 will improve anaerobic and/or aerobic exercise performance by increasing plasma and muscle CoQ10 concentrations within trained and untrained individuals. Methods Twenty-two aerobically trained and nineteen untrained male and female subjects (26.1 ± 7.6 yrs, 172 ± 8.7 cm, 73.5 ± 17 kg, and 21.2 ± 7.0%) were randomized to ingest in a double-blind manner either 100 mg of a dextrose placebo (CON) or a fast-melt CoQ10 supplement (CoQ10) twice a day for 14-days. On the first day of supplementation, subjects donated fasting blood samples and a muscle biopsy. Subjects were then given 200 mg of the placebo or the CoQ10 supplement. Sixty minutes following supplement ingestion, subjects completed an isokinetic knee extension endurance test, a 30-second wingate anaerobic capacity test, and a maximal cardiopulmonary graded exercise test interspersed with 30-minutes of recovery. Additional blood ...