Matthew D. Vukovich

Carnitine supplementation: effect on muscle carnitine and glycogen content during exercise.

This study investigated the effects of L-carnitine supplementation on muscle carnitine and glycogen content during submaximal exercise (EX). Triglycerides were evaluated by a fat feeding (90 g fat) and 3 h later subjects cycled for 60 min at 70% VO2max (CON). Muscle biopsies were obtained preexercise and after 30 and 60 min of EX. Blood samples were taken prior to and every 15 min of exercise. Subjects randomly completed two additional trials following 7 and 14 d of carnitine supplementation (6 g.d-1). During one of the two trials, subjects received 2000 units of heparin 15 min prior to EX to elevate FFA (CNhep); no heparin was administered during the other trial (CN). There were no differences in VO2, respiratory exchange ratio, heart rate, or g.min-1 of CHO and fat oxidized among the three trials. At rest serum total acid soluble (TASC) and free (FC) carnitine increased with supplementation (TASC; CON, 71.3 +/- 2.9; CN, 92.8 +/- 5.4; CNhep, 109.8 +/- 3.5 mumol.l-1) (FC; CON, 44.1 +/- 2.7; CN, 66.1 +/- 5.3; CNhep, 77.1 +/- 4.1 mumol.l-1). During EX, TASC remained stable, while FC decreased and short-chain acylcarnitine (SCAC) increased (P < 0.05). Muscle carnitine concentration at rest was unaffected by supplementation. During EX, muscle TASC did not change, FC decreased, and SCAC increased significantly in all three trials. Pre-EX and post-EX muscle glycogens were not different. Increased availability of serum carnitine does not result in an increase in muscle carnitine content nor does it alter lipid oxidation. It appears that there is an adequate amount of carnitine present within the mitochondria to support lipid oxidation.

Endocrine and Lipid Responses to Chronic Androstenediol-Herbal Supplementation in 30 to 58 Year Old Men

Objective: The effectiveness of an androgenic nutritional supplement designed to enhance serum testosterone concentrations and prevent the formation of dihydrotestosterone and estrogen was investigated in healthy 30 to 58 year old men. Design: Subjects were randomly assigned to consume a nutritional supplement (AND-HB) containing 300-mg androstenediol, 480-mg saw palmetto, 450-mg indole-3-carbinol, 300-mg chrysin, 1,500 mg gamma-linolenic acid and 1,350-mg Tribulus terrestris per day (n = 28), or placebo (n = 27) for 28 days. Subjects were stratified into age groups to represent the fourth (30 year olds, n = 20), fifth (40 year olds, n = 20) and sixth (50 year olds, n = 16) decades of life. Measurements: Serum free testosterone, total testosterone, androstenedione, dihydrotestosterone, estradiol, prostate specific antigen and lipid concentrations were measured before supplementation and weekly for four weeks. Results: Basal serum total testosterone, estradiol, and prostate specific antigen (PSA) concentrations were not different between age groups. Basal serum free testosterone concentrations were higher (p < 0.05) in the 30- (70.5 ± 3.6 pmol/L) than in the 50 year olds (50.8 ± 4.5 pmol/L). Basal serum androstenedione and dihydrotestosterone (DHT) concentrations were significantly higher in the 30- (for androstenedione and DHT, respectively, 10.4 ± 0.6 nmol/L and 2198.2 ± 166.5 pmol/L) than in the 40- (6.8 ± 0.5 nmol/L and 1736.8 ± 152.0 pmol/L) or 50 year olds (6.0 ± 0.7 nmol/L and 1983.7 ± 147.8 pmol/L). Basal serum hormone concentrations did not differ between the treatment groups. Serum concentrations of total testosterone and PSA were unchanged by supplementation. Ingestion of AND-HB resulted in increased (p < 0.05) serum androstenedione (174%), free testosterone (37%), DHT (57%) and estradiol (86%) throughout the four weeks. There was no relationship between the increases in serum free testosterone, androstenedione, DHT, or estradiol and age (r2 = 0.08, 0.03, 0.05 and 0.02, respectively). Serum HDL-C concentrations were reduced (p < 0.05) by 0.14 mmol/L in AND-HB. Conclusions: These data indicate that ingestion of androstenediol combined with herbal products does not prevent the formation of estradiol and dihydrotestosterone.

Evidence for an interaction between exercise and nutrition for improved bone health during growth.

Exercise and nutrition are independently recognized as important modifiable lifestyle factors essential for optimal bone health during growth. In this review, we discuss the effect of dietary calcium, vitamin D and protein alone and in combination with exercise on bone mass and strength in children and adolescents. Recent intervention studies in children now provide evidence that exercise and calcium may interact with each other to enhance bone health, but the mechanism underlying this effect is not well understood. Vitamin D is also important for bone health through its action on calcium absorption, and both dietary protein and total energy intake can also alter bone metabolism through their influence on growth factors such as insulin-like growth factor I. However, whether these factors act synergistically with exercise to enhance bone accrual has not been examined. Therefore, while exercise and nutrition are both independently important for skeletal development, there remain many unanswered questions as to whether combinations of these factors interact to enhance skeletal health during growth. Current evidence suggests that regular weight-bearing exercise and adequate dietary calcium intakes (around 1,000 mg per day) may be required to optimize bone health; however, exercise would appear to be more important for optimizing bone strength because it has a direct effect (e.g. via loading) on bone mass and structural properties, whereas nutritional factors appear to have an indirect effect (e.g. via hormonal factors) on bone mass.

Moderate protein intake improves total and regional body composition and insulin sensitivity in overweight adults

A high protein intake (approximately 40% of energy intake) combined with aerobic and resistance exercise training is more closely associated with improved body composition and cardiovascular risk profile than a traditional protein intake (approximately 15% of intake) combined with moderate-intensity aerobic exercise. However, there is concern that such high-protein diets may adversely affect health. We therefore tested the hypothesis that moderate protein intake (approximately 25% of energy intake) would elicit similar benefits on body composition and metabolic profile as high protein intake. Twenty-four overweight/obese men and women (body mass index [BMI] = 32.2 +/- 3.4, percentage of body fat [%BF] = 37.3 +/- 8.0) were matched for BMI and %BF and randomly assigned to one of 3 groups for a 3-month nutrition/exercise training intervention: (1) high-protein diet (approximately 40% of energy intake) and combined high-intensity resistance and cardiovascular training (HPEx, n = 8, 5 female and 3 male), (2) moderate-protein diet (approximately 25% of energy intake) and combined high-intensity resistance and cardiovascular training (MPEx, n = 8, 5 female and 3 male), or (3) high-protein diet only (HPNx, n = 8, 5 female and 3 male). Total and regional body composition (dual-energy x-ray absorptiometry), insulin sensitivity (insulin sensitivity index to the oral glucose tolerance test), insulin-like growth factor-1 (IGF-1), IGF binding protein-1 (IGFBP-1), IGF binding protein-3 (IGFBP-3), and blood lipids were measured at baseline and after the intervention. All groups experienced significant (P < .05) and similar losses of body weight, BMI, and total and abdominal %BF, and similar improvements in insulin sensitivity (HPEx, 6.3 +/- 1.2 vs 9.5 +/- 0.98; MPEx, 6.2 +/- 1.4 vs 8.4 +/- 1.6; HPNx, 3.7 +/- 1.1 vs 7.0 +/- 1.1; insulin sensitivity index to the oral glucose tolerance test; P < .05) and leptin levels. Furthermore, the HPEx group demonstrated decreases in total cholesterol (TC) and triglycerides, and increases in IGF-1 and IGFBP-1. The MPEx group experienced decreases in TC, whereas the HPNx group had increases in high-density lipoprotein cholesterol, TC to high-density lipoprotein, IGF-1, and IGFBP-1. In conclusion, moderate protein intake elicits similar benefits in body composition and insulin sensitivity as a high-protein diet. These findings may have practical implications for individuals interested in diets containing elevated dietary protein.

β-hydroxy-β-methylbutyrate (HMB) kinetics and the influence of glucose ingestion in humans

Abstract The dietary supplement, β-hydroxy-β-methylbutyrate (HMB), has been shown to decrease muscle proteolysis during the stress of exercise and disease. The aim of this investigation was to determine the time course kinetics of HMB and to determine whether oral glucose ingestion alters the kinetics. In Study 1, eight males (32 ± 10 yrs) participated in two randomize trials: 1) oral ingestion of 1g of HMB with water in capsule form (HMB), and 2) placebo. Blood samples were obtained prior to ingestion of treatment and at 30, 60, 90, 120, 150, and 180 min for the measurement of plasma HMB. Additional blood samples were obtained at 6, 9, and 12 hr. Urine was collected prior to ingestion and at 3, 6, 9, and 12 h for the measurement of urinary HMB. In Study 2, eight males (25 ± 6 yrs) followed the same study design and testing procedure as for Study 1. Treatments were 1) modified glucose tolerance test (75 g glucose) (GLU), 2) oral ingestion of 3 g of HMB with water (HMB), and 3) ingestion of 3 g of HMB with 75 g of glucose (HMB+GLU). Blood samples were analyzed for insulin, glucose, and HMB. Additional blood samples were obtained at 24h and 36h for the measurement of HMB. Additional urine samples were collected at 24h and 36h. In Study 1, plasma HMB peaked at 120 nmol/ml at 2.0 ± 0.4 hr in HMB trial. Half-life was 2.37 ± 0.1 hr. Following the consumption of 1g of HMB, ∼14% of the HMB consumed accumulated in the urine. In Study 2, plasma glucose and insulin levels were significantly greater in GLU and HMB+GLU treated subjects compared to HMB treated subject at minutes 30, 60 and 90. Plasma HMB peaked at 487.9 ± 19.0 nmol/ml at 1.0 ± 0.1 hr in the HMB treated subjects and at 352.1 ± 15.3 nmol/ml at 1.94 ± 0.2 hr when subjects consumed HMB+GLU. The time to reach peak was different (P

Caffeine-herbal ephedra combination increases resting energy expenditure, heart rate and blood pressure.

1. The purpose of the present study was to determine whether the consumption of an acute dose of caffeine and Ma Huang increases resting energy expenditure (REE), heart rate (HR) and blood pressure (BP) over a 3 h period.

Effects of androstenedione-herbal supplementation on serum sex hormone concentrations in 30- to 59-year-old men.

The effectiveness of a nutritional supplement designed to enhance serum testosterone concentrations and prevent the formation of dihydrotestosterone and estrogens from the ingested androgens was investigated in healthy 30- to 59-year old men. Subjects were randomly assigned to consume DION (300 mg androstenedione, 150 mg dehydroepiandrosterone, 540 mg saw palmetto, 300 mg indole-3-carbinol, 625 mg chrysin, and 750 mg Tribulus terrestris per day; n = 28) or placebo (n = 27) for 28 days. Serum free testosterone, total testosterone, androstenedione, dihydrotestosterone, estradiol, prostate-specific antigen (PSA), and lipid concentrations were measured before and throughout the 4-week supplementation period. Serum concentrations of total testosterone and PSA were unchanged by supplementation. DION increased (p < 0.05) serum androstenedione (342%), free testosterone (38%), dihydrotestosterone (71%), and estradiol (103%) concentrations. Serum HDL-C concentrations were reduced by 5.0 mg/dL in DION (p < 0.05). Increases in serum free testosterone (r2 = 0.01), androstenedione (r2 = 0.01), dihydrotestosterone (r2 = 0.03), or estradiol (r2 = 0.07) concentrations in DION were not related to age. While the ingestion of androstenedione combined with herbal products increased serum free testosterone concentrations in older men, these herbal products did not prevent the conversion of ingested androstenedione to estradiol and dihydrotestosterone.

Osteogenic Index and Changes in Bone Markers during a Jump Training Program: A Pilot Study

PURPOSE This study was designed as a proof-of-concept study to assess the osteogenic index (OI) and changes in bone markers during an 8-wk jump training program. On the basis of the OI, jumps were completed in one or two daily sessions with total jumps per day being equal. METHODS Seven males served as controls and participated in their normal strength training program. Fourteen males were divided into two groups, jumping once daily (J1x) or jumping twice daily (J2x), with a 6-h recovery period between sessions (J2x only). Jumping-type exercises were performed on a Plyo Press and started at 20 plyo-jumps per day, three times per week and progressed to 60 plyo-jumps per day, three times per week for the last 3 wk. Blood samples were collected at baseline and at 4 and 8 wk to determine serum concentrations of bone-specific alkaline phosphate and C-terminal telopeptides of type I collagen. RESULTS OI for each session and week were different (P < 0.05) between the two jumping groups (baseline OI per week, J1x = 28 +/- 0.9, J2x = 34 +/- 0.9). There was a significant change (P = 0.005) in bone-specific alkaline phosphate over time, with 8-wk values being significantly higher than baseline values (change from baseline: J1x = 2.7 +/- 1.4 microg.L-1, J2x = 3.5 +/- 1.3 microg.L-1). J2x had an overall mean change significantly different from zero. C-terminal telopeptides of type I collagen did not change significantly during the 8 wk. CONCLUSIONS The data demonstrate that the bone of young adult males does respond to a high-impact exercise. In addition, compared with completing all plyo-jumps in one session, the use of recovery periods between exercise sessions on the same day may result in positive changes in bone turnover, indicative of an osteogenic effect. The beneficial impact of the OI and how it can be used to design programs to influence bone turnover still remain to be determined.

NARINGIN DOES NOT ALTER CAFFEINE PHARMACOKINETICS, ENERGY EXPENDITURE, OR CARDIOVASCULAR HAEMODYNAMICS IN HUMANS FOLLOWING CAFFEINE CONSUMPTION

1 Naringin, a grapefruit constituent interacts with many medications including caffeine, a popular weight loss supplement. The purpose of the current study was to identify changes in caffeine pharmacokinetics, resting energy expenditure (REE), oxygen consumption (VO2) and respiratory exchange ratio (RER) after an acute dosage of caffeine and naringin. 2 Using a double‐blinded, counterbalanced design, REE, VO2, and RER were measured before and systematically for 8 h after a single dosage of caffeine (CAF, 200 mg) with and without naringin (100 mg (CN100) or 200 mg (CN200)) in 10 apparently healthy individuals. A standardized meal was provided following 240‐minute measurements (400 kcals; 35 g carbohydrate; 27 g protein; 7 g fat). 3 Caffeine, CN100, CN200 did not alter VO2 or VO2 area under the curve (137 301 ± 8318, 139 729 ± 9300, 134 297 ± 8318, mL/480 min). Resting energy expenditure (k/cals) was 10.0 ± 1.4% higher with CAF versus CN200 (6.0 ± 1.4%) and CN100 (6 ± 1.5%) at 240 min (P = 0.07) which was then negated following a standardized meal. Percent change in RER from pre to 240 min and pre to 480 min was not different between the CAF, CN100, or CN200 (–0.2 ± 1.7%, 1.7 ± 1.7%, –2.8 ± 1.9%). 4 Although caffeine alone suggests a trend of increased REE, the results of the present study indicate that concurrent consumption of caffeine with naringin in acute dosages does not affect RER, VO2, and prevents the increase of REE in adult humans. The results suggest that the interaction of grapefruit juice and caffeine may be due to constituents of grapefruit juice other than naringin or in addition to naringin.

Changes in Body Composition in Division I Football Players Over a Competitive Season and Recovery in Off-Season.

Abstract Binkley, TL, Daughters, SW, Weidauer, LA, and Vukovich, MD. Changes in body composition in Division I football players over a competitive season and recovery in off-season. J Strength Cond Res 29(9): 2503–2512, 2015—This study investigated changes in body composition over 1 competitive football season in D-I collegiate football players (N = 53; by position, 21 linemen vs. 32 nonline; or by seniority, 30 upperclassmen vs. 23 underclassmen) and additional changes by the following spring season (N = 46; 20 linemen vs. 26 nonline; 27 upperclassmen vs. 19 underclassmen). Body composition by dual-energy x-ray absorptiometry (DXA) was completed pre- and post-season and the following spring. For the team as a whole, player weight decreased 1.3 kg (1.2%) and lean mass decreased 1.4 kg (1.6%) over the season. Absolute fat mass showed no change; however, percent body fat showed a 0.5% increase. There was an interaction between player position and seniority for changes in lean mass (p < 0.01). In nonline positions upperclassmen lost more lean mass than underclassmen, whereas in line positions underclassmen lost more lean mass than upperclassmen. Spring measures indicate that weight did not increase during the off-season, but improvement in body composition was noted. Lean mass increased by 2.2 kg (2.6%), whereas absolute fat mass decreased by 1.4 kg (6.7%). Although weight and lean mass losses during the competitive season were recovered in the off-season, changes in collegiate football programs that include nutrition counseling, dietary recommendations, monitoring of weight, and skin-fold testing as an estimate of body fat change would be beneficial to players. Strength and conditioning coaches and staff need to consider strategies to incorporate these practices into their programs.