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A 2-yr Randomized Controlled Trial on Creatine Supplementation during Exercise for Postmenopausal Bone Health.
Chilibeck, PD, Candow, DG, Gordon, JJ, Duff, WRD, Mason, R, Shaw, K, Taylor-Gjevre, R, Nair, B, Zello, GA
Medicine and science in sports and exercise. 2023;55(10):1750-1760
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Osteoporosis is a bone disease that gradually develops when bone mineral density (BMD) or bone mass decreases and the quality of bone is impaired. This randomised controlled trial conducted over 2 years wanted to test the effects of creatine monohydrate supplementation on BMD at several bone sites during a supervised resistance training and walking program in post menopausal women. 120 were randomly allocated to creatine and 117 to placebo. All participants received a daily supplement of 500 mg of calcium and 10 μg -400 IU of vitamin D. The researchers were particularly interested in finding out whether the creatine group showed improved (BMD) at the femoral neck, lower spine and upper thigh bone also known as the proximal femur which connects the hip joint. Bone density scans, dual-energy X-ray’s and ultrasounds were used to measure BMD and assess areas of bone. Falls and fractures were recorded for a total of 3 years. Dietary intake and physical activity outside of study requirements was assessed using food frequency and exercise questionnaires. Fasting blood and urine analyses along with 24-h urine analysis were taken. The authors conclude that creatine supplementation during a resistance training and walking program had no effect on BMD at the femoral neck, total hip, or lower spine. They further acknowledge relatively low compliance with the creatine supplements, and exercise protocols, along with a high drop out rate. Further studies of larger sample sizes are needed.
Abstract
PURPOSE Our purpose was to examine the effects of 2 yr of creatine monohydrate supplementation and exercise on bone health in postmenopausal women. METHODS Two hundred and thirty-seven postmenopausal women (mean age, 59 yr) were randomized to receive creatine (0.14 g·kg -1 ·d -1 ) or placebo during a resistance training (3 d·wk -1 ) and walking (6 d·wk -1 ) program for 2 yr. Our primary outcome was the femoral neck bone mineral density (BMD), with lumbar spine BMD and proximal femur geometric properties as the secondary outcomes. RESULTS Compared with placebo, creatine supplementation had no effect on BMD of the femoral neck (creatine: 0.725 ± 0.110 to 0.712 ± 0.100 g·cm -2 ; placebo: 0.721 ± 0.102 to 0.706 ± 0.097 g·cm -2 ), total hip (creatine: 0.879 ± 0.118 to 0.872 ± 0.114 g·cm -2 ; placebo: 0.881 ± 0.111 to 0.873 ± 0.109 g·cm -2 ), or lumbar spine (creatine: 0.932 ± 0.133 to 0.925 ± 0.131 g·cm -2 ; placebo: 0.923 ± 0.145 to 0.915 ± 0.143 g·cm -2 ). Creatine significantly maintained section modulus (1.35 ± 0.29 to 1.34 ± 0.26 vs 1.34 ± 0.25 to 1.28 ± 0.23 cm 3 (placebo), P = 0.0011), predictive of bone bending strength, and buckling ratio (10.8 ± 2.6 to 11.1 ± 2.2 vs 11.0 ± 2.6 to 11.6 ± 2.7 (placebo), P = 0.011), predictive of reduced cortical bending under compressive loads, at the narrow part of the femoral neck. Creatine reduced walking time over 80 m (48.6 ± 5.6 to 47.1 ± 5.4 vs 48.3 ± 4.5 to 48.2 ± 4.9 s (placebo), P = 0.0008) but had no effect on muscular strength (i.e., one-repetition maximum) during bench press (32.1 ± 12.7 to 42.6 ± 14.1 vs 30.6 ± 10.9 to 41.4 ± 14 kg (placebo)) and hack squat (57.6 ± 21.6 to 84.4 ± 28.1 vs 56.6 ± 24.0 to 82.7 ± 25.0 kg (placebo)). In the subanalysis of valid completers, creatine increased lean tissue mass compared with placebo (40.8 ± 5.7 to 43.1 ± 5.9 vs 40.4 ± 5.3 to 42.0 ± 5.2 kg (placebo), P = 0.046). CONCLUSIONS Two years of creatine supplementation and exercise in postmenopausal women had no effect on BMD; yet, it improved some bone geometric properties at the proximal femur.
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Efficacy of a 2-Month Very Low-Calorie Ketogenic Diet (VLCKD) Compared to a Standard Low-Calorie Diet in Reducing Visceral and Liver Fat Accumulation in Patients With Obesity.
Cunha, GM, Guzman, G, Correa De Mello, LL, Trein, B, Spina, L, Bussade, I, Marques Prata, J, Sajoux, I, Countinho, W
Frontiers in endocrinology. 2020;11:607
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Excess fat in the liver, known as non-alcoholic fatty liver disease (NAFLD), has been shown to increase the risk of chronic diseases such as type 2 diabetes. Standard treatment regimens consist of low-calorie (LC) diets and exercise, however these may be ineffective at reversing fat accumulation in the liver. A very low-calorie ketogenic diet (VLCKD) has been proposed as an alternative treatment for NAFLD. This randomised control pilot study of 39 individuals with obesity aimed to compare LC diet and VLCKD on fat accumulation and indicators for NAFLD for two months. The results showed greater weight loss, abdominal fat reduction, liver fat reduction and improvements in liver function with VLCKD compared to the LC diet. Cholesterol was significantly reduced by both diets. However liver stiffness remained unchanged. The authors concluded that VLCKD was more successful at reducing liver fat and abdominal fat accumulation than current standard therapy and has the potential to improve NAFLD. Health care professionals could use this study to improve liver and abdominal fat loss in patients with obesity to improve NAFLD, when standard therapy has been inadequate.
Abstract
Background: Currently the treatment of non-alcoholic fatty liver disease (NAFLD) is based on weight loss through lifestyle changes, such as exercise combined with calorie-restricted dieting. Objectives: To assess the effects of a commercially available weight loss program based on a very low-calorie ketogenic diet (VLCKD) on visceral adipose tissue (VAT) and liver fat content compared to a standard low-calorie (LC) diet. As a secondary aim, we evaluated the effect on liver stiffness measurements. Methods: Open, randomized controlled, prospective pilot study. Patients were randomized and treated either with an LC or a VLCKD and received orientation and encouragement to physical activity equally for both groups. VAT, liver fat fraction, and liver stiffness were measured at baseline and after 2 months of treatment using magnetic resonance imaging. Paired t-tests were used for comparison of continuous variables between visits and unpaired test between groups. Categorical variables were compared using the χ2-test. Pearson correlation was used to assess the association between VAT, anthropometric measures, and hepatic fat fraction. A significance level of the results was established at p < 0.05. Results: Thirty-nine patients (20 with VLCKD and 19 with LC) were evaluated at baseline and 2 months of intervention. Relative weight loss at 2 months was -9.59 ± 2.87% in the VLCKD group and -1.87 ± 2.4% in the LC group (p < 0.001). Mean reductions in VAT were -32.0 cm2 for VLCKD group and -12.58 cm2 for LC group (p < 0.05). Reductions in liver fat fraction were significantly more pronounced in the VLCKD group than in the LC group (4.77 vs. 0.79%; p < 0.005). Conclusion: Patients undergoing a VLCKD achieved superior weight loss, with significant VAT and liver fat fraction reductions when compared to the standard LC diet. The weight loss and rapid mobilization of liver fat demonstrated with VLCKD could serve as an effective alternative for the treatment of NAFLD. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT04322110.
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The microbiome of professional athletes differs from that of more sedentary subjects in composition and particularly at the functional metabolic level.
Barton, W, Penney, NC, Cronin, O, Garcia-Perez, I, Molloy, MG, Holmes, E, Shanahan, F, Cotter, PD, O'Sullivan, O
Gut. 2018;67(4):625-633
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The human gut microbiome is known to actively influence metabolism, immunity and development. It has been shown that increased physical activity and healthy diet is associated with positive changes in faecal microbial diversity and composition compared with sedentary individuals. The aim of this study was to assess the metabolic activity of the microbiota between extremely active and sedentary individuals. Metabolic and genetic factors of the gut microbiome were analysed in 40 professional rugby players and 46 sedentary controls. This study found significant differences in faecal microbiota between athletes and sedentary controls at the functional metabolic level, providing deeper insight into the link between sustained physical activity and metabolic health. Based on these results, the authors conclude exercise may be an effective way to manipulate the gut microbiome and suggest further controlled trials be done to better understand the relationship between diet, exercise and the gut microbiome.
Abstract
OBJECTIVE It is evident that the gut microbiota and factors that influence its composition and activity effect human metabolic, immunological and developmental processes. We previously reported that extreme physical activity with associated dietary adaptations, such as that pursued by professional athletes, is associated with changes in faecal microbial diversity and composition relative to that of individuals with a more sedentary lifestyle. Here we address the impact of these factors on the functionality/metabolic activity of the microbiota which reveals even greater separation between exercise and a more sedentary state. DESIGN Metabolic phenotyping and functional metagenomic analysis of the gut microbiome of professional international rugby union players (n=40) and controls (n=46) was carried out and results were correlated with lifestyle parameters and clinical measurements (eg, dietary habit and serum creatine kinase, respectively). RESULTS Athletes had relative increases in pathways (eg, amino acid and antibiotic biosynthesis and carbohydrate metabolism) and faecal metabolites (eg, microbial produced short-chain fatty acids (SCFAs) acetate, propionate and butyrate) associated with enhanced muscle turnover (fitness) and overall health when compared with control groups. CONCLUSIONS Differences in faecal microbiota between athletes and sedentary controls show even greater separation at the metagenomic and metabolomic than at compositional levels and provide added insight into the diet-exercise-gut microbiota paradigm.
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Altered metabolic homeostasis is associated with appetite regulation during and following 48-h of severe energy deprivation in adults.
Karl, JP, Smith, TJ, Wilson, MA, Bukhari, AS, Pasiakos, SM, McClung, HL, McClung, JP, Lieberman, HR
Metabolism: clinical and experimental. 2016;65(4):416-27
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Intermittent periods of substantial energy deficit, common among military personnel, result in multiple endocrine and metabolic signals. To date, the association between metabolic and endocrine markers with appetite regulation remain controversial. Using a novel model, the aim of this crossover study was to determine the effects of severe energy deprivation on cognitive function, and explore the metabolic response and its impact on appetite regulation in 23 young adults. Following prescribed exercise, participants were randomised to consume an energy balanced or energy deficit diet. The findings of this study showed that during energy deprivation, metabolic homeostasis modulates appetite independent of diet volume. Though further studies are required, these results suggest that metabolic and endocrine signals are associated with adipose and lean tissue loss to restore energy balance.
Abstract
BACKGROUND Military personnel frequently endure intermittent periods of severe energy deficit which can compromise health and performance. Physiologic factors contributing to underconsumption, and the subsequent drive to overeat, are not fully characterized. This study aimed to identify associations between appetite, metabolic homeostasis and endocrine responses during and following severe, short-term energy deprivation. METHODS Twenty-three young adults (17M/6F, 21±3years, BMI 25±3kg/m(2)) participated in a randomized, controlled, crossover trial. During separate 48-h periods, participants increased habitual energy expenditure by 1647±345kcal/d (mean±SD) through prescribed exercise at 40-65% VO2peak, and consumed provided isovolumetric diets designed to maintain energy balance at the elevated energy expenditure (EB; 36±93kcal/d energy deficit) or to produce a severe energy deficit (ED; 3681±716kcal/d energy deficit). Appetite, markers of metabolic homeostasis and endocrine mediators of appetite and substrate availability were periodically measured. Ad libitum energy intake was measured over 36h following both experimental periods. RESULTS Appetite increased during ED and was greater than during EB despite maintenance of diet volume (P=0.004). Ad libitum energy intake was 907kcal/36h [95% CI: 321, 1493kcal/36h, P=0.004] higher following ED compared to following EB. Serum beta-hydroxybutyrate, free fatty acids, branched-chain amino acids, dehydroepiandrosterone-sulfate (DHEA-S) and cortisol concentrations were higher (P<0.001 for all), whereas whole-body protein balance was more negative (P<0.001), and serum glucose, insulin, and leptin concentrations were lower (P<0.001 for all) during ED relative to during EB. Cortisol concentrations, but not any other hormone or metabolic substrate, were inversely associated with satiety during EB (R(2)=0.23, P=0.04). In contrast, serum glucose and DHEA-S concentrations were inversely associated with satiety during ED (R(2)=0.68, P<0.001). No associations between physiologic variables measured during EB and ad libitum energy intake following EB were observed. However, serum leptin and net protein balance measured during ED were inversely associated with ad libitum energy intake following ED (R(2)=0.48, P=0.01). CONCLUSION These findings suggest that changes in metabolic homeostasis during energy deprivation modulate appetite independent of reductions in diet volume. Following energy deprivation, physiologic signals of adipose and lean tissue loss may drive restoration of energy balance. CLINICAL TRIALS REGISTRATION www.clinicaltrials.gov #NCT01603550.
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The fall in leptin concentration is a major determinant of the metabolic adaptation induced by caloric restriction independently of the changes in leptin circadian rhythms.
Lecoultre, V, Ravussin, E, Redman, LM
The Journal of clinical endocrinology and metabolism. 2011;96(9):E1512-6
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Weight loss induced by caloric restriction (CR) is associated with a drop in energy expenditure (EE) beyond that expected for the changes in body composition, often blunting weight loss and predisposing individuals to weight regain. Recent evidence has identified leptin to be associated with this exaggerated decrease in EE. The aim of this trial was to explore the changes in leptin over a 24-hour period in response to caloric restriction, and explore its association with metabolic adaptation. Forty-eight participants were assigned to one of four groups for six months: control, CR, CR with exercise and a low calorie diet. This study indicates that the decline in 24-hour leptin in response to CR is a significant determinant of metabolic adaptation. Based on this study, the authors conclude that this decrease in leptin may underlie the additional reduction in EE observed in individuals following diet-induced weight loss.
Abstract
CONTEXT Leptin is involved in the hormonal regulation of the reproductive, somatotropic, thyroid, and autonomic axes and ultimately in the regulation of energy balance. In parallel to the metabolic adaptation observed in response to caloric restriction (CR), plasma leptin concentrations are substantially decreased, suggesting a role for this hormone in the drop in energy expenditure beyond that predicted by the changes in body composition (metabolic adaptation). AIM: The aim of the study was to explore the changes in 24-h leptin circadian rhythm in response to CR and to investigate the relationship between these changes and metabolic adaptation. DESIGN In a randomized, controlled trial (Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy), 48 subjects were assigned to a control group or one of three CR groups for 6 months. Leptin concentration was assessed every 30 min for 24 h, and leptin circadian variations were fitted by Cosinor analysis. Sedentary energy expenditure and urinary catecholamine excretion were measured for 24 h in a metabolic chamber. RESULTS Six months of CR decreased body weight by -11.4 ± 0.6% (mean ± sem; P < 0.001). Mean 24-h circulating leptin concentration decreased by -44 ± 3% (P < 0.001), whereas leptin diurnal amplitude slightly increased over the 6 months of CR. CR caused a metabolic adaptation of -126 ± 25 kcal/d (P <0.001) and a significant decrease in urinary norepinephrine (-13 ± 3%) and T(3) concentrations (10 ± 2%). The metabolic adaptation was significantly and independently related to the changes in 24-h leptin (r(2) = 0 .22, P < 0.01) but not to the changes in leptin amplitude. CONCLUSION Our results confirm an important role for leptin as an independent determinant of the metabolic adaptation in response to CR.
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Effect of purple sweet potato leaf consumption on the modulation of the antioxidative status in basketball players during training.
Chang, WH, Chen, CM, Hu, SP, Kan, NW, Chiu, CC, Liu, JF
Asia Pacific journal of clinical nutrition. 2007;16(3):455-61
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Purple sweet potato leaves (PSPLs) have a high polyphenol content and have been shown to exhibit free-radical scavenging properties. During a training period athletes experience exercise-induced oxidative stress, and many studies have indicated that polyphenols can help prevent oxidative damage. Currently there is limited information on the physiologic and biochemical effects of dietary PSPLs in humans. The aim of this crossover study was to examine the effect of PSPLs on a variety of antioxidant status biomarkers in fifteen elite basketball players. Participants were enrolled for seven weeks and consumed a PSPL-rich diet and a control diet with a washout period in between. This study found that PSPL consumption for two weeks led to a significant increase in total plasma polyphenol concentration and vitamin E and C levels, and demonstrated a protective effect on lipid and DNA oxidation. The authors conclude that can a polyphenol-rich diet can modulate the anti-oxidative status of athletes during a training period.
Abstract
The aim of this study was to evaluate the effect of purple sweet potato leaves (PSPLs) consumption on antioxidative status and its modulation of that status in basketball players during training period. Fifteen elite basketball players were enrolled in this study. The seven-week study consisted of a run-in (week 1), PSPLs diet (daily consumption of 200 g PSPLs) (weeks 2, 3), washout (weeks 4, 5), and control diet (low polyphenol, with the amount of carotenoids adjusted to the same level as that of PSPLs) (weeks 6, 7). Blood and urine samples were taken for biochemical analysis. Compared with the control group, the results showed that PSPLs consumption led to a significant increase of plasma polyphenol concentration and vitamin E and C levels. Low density lipoprotein (LDL) lag time was significantly longer in the PSPLs group. A significant decrease of urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) was noted; however, there was no significant change in plasma glutathione (GSH), total antioxidant status (TAS) and malondialdehyde + 4-hydroxy-2(E)-nonenal level after consuming the PSPLs diet. In conclusion, consumption of PSPLs diet for 2 weeks may reduce lipid and DNA oxidation that can modulate the antioxidative status of basketball players during training period.
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Gastrointestinal permeability during exercise: effects of aspirin and energy-containing beverages.
Lambert, GP, Broussard, LJ, Mason, BL, Mauermann, WJ, Gisolfi, CV
Journal of applied physiology (Bethesda, Md. : 1985). 2001;90(6):2075-80
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Many athletes use aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) for analgesia. This study of 17 subjects aimed to assess whether the use of aspirin with prolonged exercise could increase gastrointestinal permeability. It also aimed to examine whether consumption of a carbohydrate-containing or a carbohydrate and glutamine-containing beverage could reduce this effect. Authors concluded that acute aspirin consumption before prolonged exercise could increase gastroduodenal and intestinal permeability. They also indicated that gastroduodenal permeability was significantly decreased by the ingestion of carbohydrate-containing beverages and that consumption of carbohydrate containing glutamine beverage provided no additional benefits than the carbohydrate alone beverage.
Abstract
The purpose of this study was to determine whether aspirin (A) ingestion combined with prolonged exercise increases gastrointestinal permeability and whether consumption of a carbohydrate-containing (CHO) or a CHO + glutamine-containing (CHO+G) beverage would reduce this effect. Seventeen subjects completed six experiments. They ingested A (1,300 mg) or placebo (P) pills the evening before and before running 60 min at 70% maximal oxygen uptake. Also, before running they ingested a solution containing 5 g lactulose (L), 5 g sucrose (S), and 2 g rhamnose (R). During each trial, either a 6% CHO beverage, a 6% CHO+G (0.6%; 41 mM) beverage, or a water placebo (WP) was consumed. For 4 h after a run, all urine was collected to measure urinary excretion of L, R, and S. S excretion (percentage of dose ingested; measure of gastroduodenal permeability) was significantly greater (P < 0.05) during the A trial while the subjects drank the WP compared with all other trials. Administration of A also significantly increased L/R (measure of intestinal permeability) for the CHO and WP trials compared with all P trials. Ingestion the CHO or CHO+G beverages significantly reduced S excretion and L excretion when A was administered, but it did not reduce L/R. These results indicate that gastroduodenal and intestinal permeability increase after A ingestion during prolonged running and that ingestion of a CHO beverage attenuates the gastroduodenal effect but not the intestinal effect. Furthermore, addition of G to the CHO beverage provided no additional benefit in reducing gastroduodenal or intestinal permeability.