Mark Haub | Kansas State University (original) (raw)

Papers by Mark Haub

Nutrients, Jan 1, 2010

Dietary fiber and whole grains contain a unique blend of bioactive components including resistant... more Dietary fiber and whole grains contain a unique blend of bioactive components including resistant starches, vitamins, minerals, phytochemicals and antioxidants. As a result, research regarding their potential health benefits has received considerable attention in the last several decades. Epidemiological and clinical studies demonstrate that intake of dietary fiber and whole grain is inversely related to obesity, type two diabetes, cancer and cardiovascular disease (CVD). Defining dietary fiber is a divergent process and is dependent on both nutrition and analytical concepts. The most common and accepted definition is based on nutritional physiology. Generally speaking, dietary fiber is the edible parts of plants, or similar carbohydrates, that are resistant to digestion and absorption in the small intestine. Dietary fiber can be separated into many different fractions. Recent research has begun to isolate these components and determine if increasing their levels in a diet is beneficial to human health. These fractions include arabinoxylan, inulin, pectin, bran, cellulose, β-glucan and resistant starch. The study of these components may give us a better understanding of how and why dietary fiber may decrease the risk for certain diseases. The mechanisms behind the reported effects of dietary fiber on metabolic health are not well established. It is speculated to be a result of changes in intestinal viscosity, nutrient absorption, rate of passage, production of short chain fatty acids and production of gut hormones. Given the inconsistencies reported between studies this review will examine the most up to date data concerning dietary fiber and its effects on metabolic health.

Journal of Nutrition and Metabolism, Jan 1, 2012

This study was designed to determine the efficacy of two novel type-four resistant starches (RS4)... more This study was designed to determine the efficacy of two novel type-four resistant starches (RS4) on postprandial glycemia and ratings of fullness. Volunteers (n = 10) completed completed five interventions designed to determine the glycemic and satiety (fullness) effects of the starches (38 g,) alone and when added on top of available carbohydrate. The dose of the starches provided 30 g of resistant starch per treatment. The treatments were: commercial resistant starch added to water (PF−), noncommercial resistant starch added to water (PR−), dextrose solution (DEX, 50 g), and DEX with PenFibe starch (PF+), and DEX with the noncommercial starch added (PR+). Blood glucose was measured in the fasted state and following the randomly assigned treatments at 30, 45, 60, 90, and 120 minutes post-consumption. A visual analog scale was used to determine fullness at each time point. There were no differences in the glucose incremental areas under the curve (iAUC) for PF+ and PR+ compared with DEX. The PF− and PR− treatments had decreased (P < 0.05) iAUCs for glucose compared with DEX, PF+, and PR+. There were no treatment differences for RoF. The dose (38 g) of starches did not to alter glucose responses when added on top of 50 g of dextrose.

Journal of Nutrition and Metabolism, Jan 1, 2010

The purpose of this study was to determine whether different types of resistant starch (RS) elici... more The purpose of this study was to determine whether different types of resistant starch (RS) elicited different glycemic responses. Eleven healthy subjects consumed solutions containing 30 g of either dextrose (DEX), resistant starch type 2 (RS2), or cross-linked resistant wheat starch type 4 (RS4 XL ) on three separate occasions, which were assigned randomly. Finger stick blood samples were collected before and over the following two hours and measured for glucose. The incremental area under the curve (iAUC) for the glucose response was calculated for all trials. The two types of resistant starch significantly (P < .05) decreased iAUC compared with DEX. The response with RS4 XL was significantly decreased compared with the RS2 trial. These data demonstrate that different types of resistant starch elicit significantly different glycemic responses.

The ISME Journal , Oct 4, 2012

Journal of Nutrition and Metabolism, Jan 1, 2010

Metabolic Syndrome and Related Disorders, Jan 1, 2005

... ERIC C. WESTMAN, MDMHS,1 WILLIAM S. YANCY, Jr., MDMHS,1 MARK D. HAUB, Ph.D.,2 and JEFF S. VOL... more ... ERIC C. WESTMAN, MDMHS,1 WILLIAM S. YANCY, Jr., MDMHS,1 MARK D. HAUB, Ph.D.,2 and JEFF S. VOLEK, Ph.DRD3 ... 4. Hamilton J, Cummings E, Zdravkovic V, Finegood D, Daneman D. Metformin as an adjunct therapy in adolescents with type 1 diabetes and insulin ...

Current Sports Medicine Reports, Jan 1, 2007

Athletes are continually searching for means to optimize their performance. Within the past 20 ye... more Athletes are continually searching for means to optimize their performance. Within the past 20 years, athletes and scientists have reported or observed that consuming a carbohydrate-restricted diet may improve performance. The original theories explaining the purported benefits centered on the fact that fat oxidation increases, thereby “sparing” muscle glycogen. More recent concepts that explain the plausibility of the ergogenicity of low-carbohydrate, or high-fat, diets on exercise performance pertain to an effect similar to altitude training. We and others have observed that although fat oxidation may be increased, the ability to maintain high-intensity exercise (above the lactate threshold) seems to be compromised or at least indifferent when compared with consumption of more carbohydrate. That said, clinical studies clearly demonstrate that ad libitum low-carbohydrate diets elicit greater decreases in body weight and fat than energy-equivalent low-fat diets, especially over a short duration. Thus, although low-carbohydrate and high-fat diets appear detrimental or indifferent relative to performance, they may be a faster means to achieve a more competitive body composition.

Military Medicine, Jun 1, 2012

ABSTRACT Objectives: To explore the relationship between adult attention deficit hyperactivity d... more ABSTRACT
Objectives: To explore the relationship between adult attention deficit hyperactivity disorder (ADHD) subtypes and neuropsychological functioning among U.S. soldiers. Methods: Deploying soldiers (N = 260) completed the World Health Organization Adult ADHD Self-Report Scale (ASRS) Screener. Cognitive tests, a deployment health-history questionnaire, and the post-traumatic stress disorder (PTSD) Checklist-Military Version were completed by subsamples of available participants. Results: The prevalence of positive ASRS screens was 10.4%. ASRS scores were correlated with PTSD avoidance (N = 63, ρ = 0.37, p = 0.003), hyperarousal (N = 63, ρ = 0.25, p = 0.047), and total PTSD scores (N = 62, ρ = 0.33, p = 0.009); and all six moods (e.g., anger, anxiety) scale scores (N = 110; ρ = −0.37 to 0.43). ASRS was also correlated with scores on the match-to-sample (N = 110, ρ = −0.23, p = 0.014) and emotional Stroop (N = 108, ρ = −0.23, p = 0.016) tasks. In addition, a differential pattern between subtypes of ADHD was noted with regard to cognitive functioning, mood, and combat stress symptomatology. Conclusions: Although the results are preliminary given the sample size, the prevalence and comorbidities of ADHD appear to be similar among military and nonmilitary populations.

American Journal of …, Jan 1, 2011

Age-related increases in oxidative stress contribute to impaired skeletal muscle vascular control... more Age-related increases in oxidative stress contribute to impaired skeletal muscle vascular control. However, recent evidence indicates that antioxidant treatment with tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) attenuates flow-mediated vasodilation in isolated arterioles from the highly oxidative soleus muscle of aged rats. Whether antioxidant treatment with tempol evokes similar responses in vivo at rest and during exercise in senescent individuals and whether this effect varies based on muscle fiber type composition are unknown. We tested the hypothesis that redox modulation via acute systemic tempol administration decreases vascular conductance (VC) primarily in oxidative hindlimb locomotor muscles at rest and during submaximal whole body exercise (treadmill running at 20 m/min, 5% grade) in aged rats. Eighteen old (25-26 mo) male Fischer 344 x Brown Norway rats were assigned to either rest (n = 8) or exercise (n = 10) groups. Regional VC was determined via radiolabeled microspheres before and after intra-arterial administration of tempol (302 μmol/kg). Tempol decreased mean arterial pressure significantly by 9% at rest and 16% during exercise. At rest, similar VC in 26 out of 28 individual hindlimb muscles or muscle parts following tempol administration compared with control resulted in unchanged total hindlimb muscle VC (control: 0.18 ± 0.02; tempol: 0.17 ± 0.05 ml·min(-1)·100 g(-1)·mmHg(-1); P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). During exercise, all individual hindlimb muscles or muscle parts irrespective of fiber type composition exhibited either an increase or no change in VC with tempol (i.e., ↑11 and ↔17 muscles or muscle parts), such that total hindlimb VC increased by 25% (control: 0.93 ± 0.04; tempol: 1.15 ± 0.09 ml·min(-1)·100 g(-1)·mmHg(-1); P ≤ 0.05). These results demonstrate that acute systemic administration of the antioxidant tempol significantly impacts the control of regional vascular tone in vivo presumably via redox modulation and improves skeletal muscle vasodilation independently of fiber type composition during submaximal whole body exercise in aged rats.

The Journals …, Jan 1, 2001

BackgroundFor elderly women, insufficient data exist to assess the accuracy of the assumed mean p... more BackgroundFor elderly women, insufficient data exist to assess the accuracy of the assumed mean protein requirement of 0.6 g of protein · kg−1 · day−1, and the adequacy of the current Recommended Dietary Allowance (RDA) of 0.8 g of protein · kg−1 · day−1. The aims of this study were to assess the mean protein requirement and suggested safe and adequate protein intake (protein allowance) of elderly women using a shorter-term nitrogen balance protocol.MethodsDuring three separate 18-day trials, 11 elderly women (age range, 70–81 years) were randomly fed eucaloric diets designed to provide either 0.50, 0.75, or 1.00 g of protein · kg−1 · day−1. Nitrogen balance was determined at Weeks 2 and 3 (Days 7–10 and 14–17, respectively) of each trial using data from total nitrogen analyses of duplicate food composites, 24-hour urine collections, and stool collections. The mean protein requirement was calculated using linear regression of individual women's data from all three trials and inverse prediction.ResultsAt protein intakes of 0.53 ± 0.02, 0.76 ± 0.02, or 1.06 ± 0.05 g of protein · kg−1 · day−1, net nitrogen balances during Week 2 were −14.5 ± 3.1, 3.8 ± 2.5 and 23.4 ± 3.3 mg of nitrogen · kg−1 · day−1, respectively, for these body weight– and body composition–stable women. At Week 3, the net nitrogen balances were −0.1 ± 2.7, 8.5 ± 3.6 and 42.0 ± 3.0 mg of nitrogen · kg−1 · day−1. From Week 2 to Week 3, shifts to more positive nitrogen balances occurred due to decreases in urinary nitrogen excretion. The mean protein requirement at Week 2 was calculated to be 0.70 ± 0.09 g of protein · kg−1 · day−1 (coefficient of variation [CV] = 13%) and at Week 3 was calculated to be 0.56 ± 0.09 g of protein · kg−1 · day−1 (CV = 17%). From these data, an adequate protein allowance was estimated to be greater than the RDA at Week 2 (0.90 g of protein · kg−1 · day [d]−1), and not different than the RDA at Week 3 (0.76 g of protein · kg−1 · d−1).ConclusionsThe decrease over time in urinary nitrogen excretion from Week 2 to Week 3 suggests that these elderly women did not achieve a metabolic steady state during this shorter-term nitrogen balance study. Collectively, these data suggest that the total protein needs of elderly women are at or above the current RDA for protein. However, the results of this study indicate that shorter-term nitrogen balance protocols are insufficient to firmly establish the RDA for protein of elderly women, and further research is required using alternative criteria measures.

Nutritional ergogenic aids, Jan 1, 2004

Abstract It is obvious that buffers elicit a physiological response by increasing the buffering c... more Abstract It is obvious that buffers elicit a physiological response by increasing the buffering capacity of blood and muscle. Also, there is convincing data that these compounds can enhance performance. 51 However, an athlete&amp;amp;#x27;s decision to use these compounds should ...

Perceptual and Motor Skills, Jan 1, 2008

Volume

The user has requested enhancement of the downloaded file.

journals.humankinetics.com, Jan 1, 2007

To illustrate the effects of low-carbohydrate (LC) and grain-based (GB) diets on body composition... more To illustrate the effects of low-carbohydrate (LC) and grain-based (GB) diets on body composition, biomarkers, athletic training, and performance in an elite triathlete. Methods: The athlete followed 2 dietary interventions for 14 d while maintaining a prescheduled training program. Pre-and postintervention measurements for each diet included plasma and serum samples, resting energy expenditure, body composition, and a performance bike ride. Results: Compared with the GB diet, the LC diet elicited more disruptions to training and unfavorable subjective experiences. Total cholesterol, HDL cholesterol, LDL cholesterol, ratings of perceived exertion, and heart rate were elevated in the LC diet. Blood insulin, resting lactate, postexercise lactate, and C-reactive protein were lowest in the LC diet. Conclusion: The LC diet resulted in both favorable and unfavorable outcomes. The primary observation was a disruption to scheduled training on the LC diet. Researchers should consider how the potential mediating effect of disruptions to training could influence pretest-posttest designs.

Background: Aging is associated with reductions in muscle mass and strength, but nutrition and ex... more Background: Aging is associated with reductions in muscle mass and strength, but nutrition and exercise interventions can delay this progression and enhance the quality of life. Objective: We examined whether the predominant source of protein consumed by older men influenced measures of muscle size and strength, body composition, resting energy expenditure, and skeletal muscle creatine concentrations in response to 12 wk of resistive training. Design: After consuming a lactoovovegetarian (LOV) diet for 2 wk, 21 men aged 65 ± 5 y were randomly assigned to either consume a beef-containing (BC) diet (n = 10) or to continue the LOV diet (n = 11) throughout resistive training. The BC diet included 0.6 g protein · kg Ϫ1 · d Ϫ1 from beef and the LOV diet included 0.6 g protein · kg Ϫ1 · d Ϫ1 from textured vegetable protein (soy) sources. The remaining protein in the diets came from self-selected LOV sources. Results: The mean total protein intake for both groups ranged from 1.03 to 1.17 g · kg Ϫ1 · d Ϫ1 during the intervention. Men in both groups had improvements (14-38%) in maximal dynamic strength of all the muscle groups trained with no significant difference between groups. With resistive training, cross-sectional muscle area of the vastus lateralis increased in both groups (4.2 ± 3.0% and 6.0 ± 2.6% for the LOV and BC groups, respectively) with no significant difference between groups. Body composition, resting energy expenditure, and concentrations of muscle creatine, phosphocreatine, and total creatine did not differ significantly between groups or change over time. Conclusions: These data suggest that increases in muscle strength and size were not influenced by the predominant source of protein consumed by older men with adequate total protein intake.

Medicine and Science in Sports and Exercise, Jan 1, 1999

International journal of …, Jan 1, 2005

The purpose of this investigation was to clarify, via a meta-analysis, whether the literature fav... more The purpose of this investigation was to clarify, via a meta-analysis, whether the literature favors a high-fat or a high-carbohydrate diet to yield superior endurance exercise performance. Twenty published trials were analyzed to compare exercise performance under different diets. The average effect size of -0.60 indicated that subjects following a high-carbohydrate diet exercised longer until exhaustion. The training status of subjects (trained vs. untrained) was significantly related to effect size (r = -0.576, P < 0.01) and effect sizes separated between trained and untrained subjects were -0.05 and -2.84 respectively. The test for homogeneity revealed significant heterogeneity among effect sizes (χ 2 [19] = 43.30, P < 0.05), indicating all of the trials are not describing the same effect. Given this significant heterogeneity, a conclusive endorsement of a high-carbohydrate diet based on the literature is difficult to make. Highly dissimilar trial protocols are the primary reason for heterogeneity.

Medicine and Science in Sports and Exercise, Jan 1, 2006

HortTechnology, Jan 1, 2008

Nutrients, Jan 1, 2010

Dietary fiber and whole grains contain a unique blend of bioactive components including resistant... more Dietary fiber and whole grains contain a unique blend of bioactive components including resistant starches, vitamins, minerals, phytochemicals and antioxidants. As a result, research regarding their potential health benefits has received considerable attention in the last several decades. Epidemiological and clinical studies demonstrate that intake of dietary fiber and whole grain is inversely related to obesity, type two diabetes, cancer and cardiovascular disease (CVD). Defining dietary fiber is a divergent process and is dependent on both nutrition and analytical concepts. The most common and accepted definition is based on nutritional physiology. Generally speaking, dietary fiber is the edible parts of plants, or similar carbohydrates, that are resistant to digestion and absorption in the small intestine. Dietary fiber can be separated into many different fractions. Recent research has begun to isolate these components and determine if increasing their levels in a diet is beneficial to human health. These fractions include arabinoxylan, inulin, pectin, bran, cellulose, β-glucan and resistant starch. The study of these components may give us a better understanding of how and why dietary fiber may decrease the risk for certain diseases. The mechanisms behind the reported effects of dietary fiber on metabolic health are not well established. It is speculated to be a result of changes in intestinal viscosity, nutrient absorption, rate of passage, production of short chain fatty acids and production of gut hormones. Given the inconsistencies reported between studies this review will examine the most up to date data concerning dietary fiber and its effects on metabolic health.

Journal of Nutrition and Metabolism, Jan 1, 2012

This study was designed to determine the efficacy of two novel type-four resistant starches (RS4)... more This study was designed to determine the efficacy of two novel type-four resistant starches (RS4) on postprandial glycemia and ratings of fullness. Volunteers (n = 10) completed completed five interventions designed to determine the glycemic and satiety (fullness) effects of the starches (38 g,) alone and when added on top of available carbohydrate. The dose of the starches provided 30 g of resistant starch per treatment. The treatments were: commercial resistant starch added to water (PF−), noncommercial resistant starch added to water (PR−), dextrose solution (DEX, 50 g), and DEX with PenFibe starch (PF+), and DEX with the noncommercial starch added (PR+). Blood glucose was measured in the fasted state and following the randomly assigned treatments at 30, 45, 60, 90, and 120 minutes post-consumption. A visual analog scale was used to determine fullness at each time point. There were no differences in the glucose incremental areas under the curve (iAUC) for PF+ and PR+ compared with DEX. The PF− and PR− treatments had decreased (P < 0.05) iAUCs for glucose compared with DEX, PF+, and PR+. There were no treatment differences for RoF. The dose (38 g) of starches did not to alter glucose responses when added on top of 50 g of dextrose.

Journal of Nutrition and Metabolism, Jan 1, 2010

The purpose of this study was to determine whether different types of resistant starch (RS) elici... more The purpose of this study was to determine whether different types of resistant starch (RS) elicited different glycemic responses. Eleven healthy subjects consumed solutions containing 30 g of either dextrose (DEX), resistant starch type 2 (RS2), or cross-linked resistant wheat starch type 4 (RS4 XL ) on three separate occasions, which were assigned randomly. Finger stick blood samples were collected before and over the following two hours and measured for glucose. The incremental area under the curve (iAUC) for the glucose response was calculated for all trials. The two types of resistant starch significantly (P < .05) decreased iAUC compared with DEX. The response with RS4 XL was significantly decreased compared with the RS2 trial. These data demonstrate that different types of resistant starch elicit significantly different glycemic responses.

The ISME Journal , Oct 4, 2012

Journal of Nutrition and Metabolism, Jan 1, 2010

Metabolic Syndrome and Related Disorders, Jan 1, 2005

... ERIC C. WESTMAN, MDMHS,1 WILLIAM S. YANCY, Jr., MDMHS,1 MARK D. HAUB, Ph.D.,2 and JEFF S. VOL... more ... ERIC C. WESTMAN, MDMHS,1 WILLIAM S. YANCY, Jr., MDMHS,1 MARK D. HAUB, Ph.D.,2 and JEFF S. VOLEK, Ph.DRD3 ... 4. Hamilton J, Cummings E, Zdravkovic V, Finegood D, Daneman D. Metformin as an adjunct therapy in adolescents with type 1 diabetes and insulin ...

Current Sports Medicine Reports, Jan 1, 2007

Athletes are continually searching for means to optimize their performance. Within the past 20 ye... more Athletes are continually searching for means to optimize their performance. Within the past 20 years, athletes and scientists have reported or observed that consuming a carbohydrate-restricted diet may improve performance. The original theories explaining the purported benefits centered on the fact that fat oxidation increases, thereby “sparing” muscle glycogen. More recent concepts that explain the plausibility of the ergogenicity of low-carbohydrate, or high-fat, diets on exercise performance pertain to an effect similar to altitude training. We and others have observed that although fat oxidation may be increased, the ability to maintain high-intensity exercise (above the lactate threshold) seems to be compromised or at least indifferent when compared with consumption of more carbohydrate. That said, clinical studies clearly demonstrate that ad libitum low-carbohydrate diets elicit greater decreases in body weight and fat than energy-equivalent low-fat diets, especially over a short duration. Thus, although low-carbohydrate and high-fat diets appear detrimental or indifferent relative to performance, they may be a faster means to achieve a more competitive body composition.

Military Medicine, Jun 1, 2012

ABSTRACT Objectives: To explore the relationship between adult attention deficit hyperactivity d... more ABSTRACT
Objectives: To explore the relationship between adult attention deficit hyperactivity disorder (ADHD) subtypes and neuropsychological functioning among U.S. soldiers. Methods: Deploying soldiers (N = 260) completed the World Health Organization Adult ADHD Self-Report Scale (ASRS) Screener. Cognitive tests, a deployment health-history questionnaire, and the post-traumatic stress disorder (PTSD) Checklist-Military Version were completed by subsamples of available participants. Results: The prevalence of positive ASRS screens was 10.4%. ASRS scores were correlated with PTSD avoidance (N = 63, ρ = 0.37, p = 0.003), hyperarousal (N = 63, ρ = 0.25, p = 0.047), and total PTSD scores (N = 62, ρ = 0.33, p = 0.009); and all six moods (e.g., anger, anxiety) scale scores (N = 110; ρ = −0.37 to 0.43). ASRS was also correlated with scores on the match-to-sample (N = 110, ρ = −0.23, p = 0.014) and emotional Stroop (N = 108, ρ = −0.23, p = 0.016) tasks. In addition, a differential pattern between subtypes of ADHD was noted with regard to cognitive functioning, mood, and combat stress symptomatology. Conclusions: Although the results are preliminary given the sample size, the prevalence and comorbidities of ADHD appear to be similar among military and nonmilitary populations.

American Journal of …, Jan 1, 2011

Age-related increases in oxidative stress contribute to impaired skeletal muscle vascular control... more Age-related increases in oxidative stress contribute to impaired skeletal muscle vascular control. However, recent evidence indicates that antioxidant treatment with tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) attenuates flow-mediated vasodilation in isolated arterioles from the highly oxidative soleus muscle of aged rats. Whether antioxidant treatment with tempol evokes similar responses in vivo at rest and during exercise in senescent individuals and whether this effect varies based on muscle fiber type composition are unknown. We tested the hypothesis that redox modulation via acute systemic tempol administration decreases vascular conductance (VC) primarily in oxidative hindlimb locomotor muscles at rest and during submaximal whole body exercise (treadmill running at 20 m/min, 5% grade) in aged rats. Eighteen old (25-26 mo) male Fischer 344 x Brown Norway rats were assigned to either rest (n = 8) or exercise (n = 10) groups. Regional VC was determined via radiolabeled microspheres before and after intra-arterial administration of tempol (302 μmol/kg). Tempol decreased mean arterial pressure significantly by 9% at rest and 16% during exercise. At rest, similar VC in 26 out of 28 individual hindlimb muscles or muscle parts following tempol administration compared with control resulted in unchanged total hindlimb muscle VC (control: 0.18 ± 0.02; tempol: 0.17 ± 0.05 ml·min(-1)·100 g(-1)·mmHg(-1); P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). During exercise, all individual hindlimb muscles or muscle parts irrespective of fiber type composition exhibited either an increase or no change in VC with tempol (i.e., ↑11 and ↔17 muscles or muscle parts), such that total hindlimb VC increased by 25% (control: 0.93 ± 0.04; tempol: 1.15 ± 0.09 ml·min(-1)·100 g(-1)·mmHg(-1); P ≤ 0.05). These results demonstrate that acute systemic administration of the antioxidant tempol significantly impacts the control of regional vascular tone in vivo presumably via redox modulation and improves skeletal muscle vasodilation independently of fiber type composition during submaximal whole body exercise in aged rats.

The Journals …, Jan 1, 2001

BackgroundFor elderly women, insufficient data exist to assess the accuracy of the assumed mean p... more BackgroundFor elderly women, insufficient data exist to assess the accuracy of the assumed mean protein requirement of 0.6 g of protein · kg−1 · day−1, and the adequacy of the current Recommended Dietary Allowance (RDA) of 0.8 g of protein · kg−1 · day−1. The aims of this study were to assess the mean protein requirement and suggested safe and adequate protein intake (protein allowance) of elderly women using a shorter-term nitrogen balance protocol.MethodsDuring three separate 18-day trials, 11 elderly women (age range, 70–81 years) were randomly fed eucaloric diets designed to provide either 0.50, 0.75, or 1.00 g of protein · kg−1 · day−1. Nitrogen balance was determined at Weeks 2 and 3 (Days 7–10 and 14–17, respectively) of each trial using data from total nitrogen analyses of duplicate food composites, 24-hour urine collections, and stool collections. The mean protein requirement was calculated using linear regression of individual women's data from all three trials and inverse prediction.ResultsAt protein intakes of 0.53 ± 0.02, 0.76 ± 0.02, or 1.06 ± 0.05 g of protein · kg−1 · day−1, net nitrogen balances during Week 2 were −14.5 ± 3.1, 3.8 ± 2.5 and 23.4 ± 3.3 mg of nitrogen · kg−1 · day−1, respectively, for these body weight– and body composition–stable women. At Week 3, the net nitrogen balances were −0.1 ± 2.7, 8.5 ± 3.6 and 42.0 ± 3.0 mg of nitrogen · kg−1 · day−1. From Week 2 to Week 3, shifts to more positive nitrogen balances occurred due to decreases in urinary nitrogen excretion. The mean protein requirement at Week 2 was calculated to be 0.70 ± 0.09 g of protein · kg−1 · day−1 (coefficient of variation [CV] = 13%) and at Week 3 was calculated to be 0.56 ± 0.09 g of protein · kg−1 · day−1 (CV = 17%). From these data, an adequate protein allowance was estimated to be greater than the RDA at Week 2 (0.90 g of protein · kg−1 · day [d]−1), and not different than the RDA at Week 3 (0.76 g of protein · kg−1 · d−1).ConclusionsThe decrease over time in urinary nitrogen excretion from Week 2 to Week 3 suggests that these elderly women did not achieve a metabolic steady state during this shorter-term nitrogen balance study. Collectively, these data suggest that the total protein needs of elderly women are at or above the current RDA for protein. However, the results of this study indicate that shorter-term nitrogen balance protocols are insufficient to firmly establish the RDA for protein of elderly women, and further research is required using alternative criteria measures.

Nutritional ergogenic aids, Jan 1, 2004

Abstract It is obvious that buffers elicit a physiological response by increasing the buffering c... more Abstract It is obvious that buffers elicit a physiological response by increasing the buffering capacity of blood and muscle. Also, there is convincing data that these compounds can enhance performance. 51 However, an athlete&amp;amp;#x27;s decision to use these compounds should ...

Perceptual and Motor Skills, Jan 1, 2008

Volume

The user has requested enhancement of the downloaded file.

journals.humankinetics.com, Jan 1, 2007

To illustrate the effects of low-carbohydrate (LC) and grain-based (GB) diets on body composition... more To illustrate the effects of low-carbohydrate (LC) and grain-based (GB) diets on body composition, biomarkers, athletic training, and performance in an elite triathlete. Methods: The athlete followed 2 dietary interventions for 14 d while maintaining a prescheduled training program. Pre-and postintervention measurements for each diet included plasma and serum samples, resting energy expenditure, body composition, and a performance bike ride. Results: Compared with the GB diet, the LC diet elicited more disruptions to training and unfavorable subjective experiences. Total cholesterol, HDL cholesterol, LDL cholesterol, ratings of perceived exertion, and heart rate were elevated in the LC diet. Blood insulin, resting lactate, postexercise lactate, and C-reactive protein were lowest in the LC diet. Conclusion: The LC diet resulted in both favorable and unfavorable outcomes. The primary observation was a disruption to scheduled training on the LC diet. Researchers should consider how the potential mediating effect of disruptions to training could influence pretest-posttest designs.

Background: Aging is associated with reductions in muscle mass and strength, but nutrition and ex... more Background: Aging is associated with reductions in muscle mass and strength, but nutrition and exercise interventions can delay this progression and enhance the quality of life. Objective: We examined whether the predominant source of protein consumed by older men influenced measures of muscle size and strength, body composition, resting energy expenditure, and skeletal muscle creatine concentrations in response to 12 wk of resistive training. Design: After consuming a lactoovovegetarian (LOV) diet for 2 wk, 21 men aged 65 ± 5 y were randomly assigned to either consume a beef-containing (BC) diet (n = 10) or to continue the LOV diet (n = 11) throughout resistive training. The BC diet included 0.6 g protein · kg Ϫ1 · d Ϫ1 from beef and the LOV diet included 0.6 g protein · kg Ϫ1 · d Ϫ1 from textured vegetable protein (soy) sources. The remaining protein in the diets came from self-selected LOV sources. Results: The mean total protein intake for both groups ranged from 1.03 to 1.17 g · kg Ϫ1 · d Ϫ1 during the intervention. Men in both groups had improvements (14-38%) in maximal dynamic strength of all the muscle groups trained with no significant difference between groups. With resistive training, cross-sectional muscle area of the vastus lateralis increased in both groups (4.2 ± 3.0% and 6.0 ± 2.6% for the LOV and BC groups, respectively) with no significant difference between groups. Body composition, resting energy expenditure, and concentrations of muscle creatine, phosphocreatine, and total creatine did not differ significantly between groups or change over time. Conclusions: These data suggest that increases in muscle strength and size were not influenced by the predominant source of protein consumed by older men with adequate total protein intake.

Medicine and Science in Sports and Exercise, Jan 1, 1999

International journal of …, Jan 1, 2005

The purpose of this investigation was to clarify, via a meta-analysis, whether the literature fav... more The purpose of this investigation was to clarify, via a meta-analysis, whether the literature favors a high-fat or a high-carbohydrate diet to yield superior endurance exercise performance. Twenty published trials were analyzed to compare exercise performance under different diets. The average effect size of -0.60 indicated that subjects following a high-carbohydrate diet exercised longer until exhaustion. The training status of subjects (trained vs. untrained) was significantly related to effect size (r = -0.576, P < 0.01) and effect sizes separated between trained and untrained subjects were -0.05 and -2.84 respectively. The test for homogeneity revealed significant heterogeneity among effect sizes (χ 2 [19] = 43.30, P < 0.05), indicating all of the trials are not describing the same effect. Given this significant heterogeneity, a conclusive endorsement of a high-carbohydrate diet based on the literature is difficult to make. Highly dissimilar trial protocols are the primary reason for heterogeneity.

Medicine and Science in Sports and Exercise, Jan 1, 2006

HortTechnology, Jan 1, 2008