New strategies in sport nutrition to increase exercise performance

Effects of beetroot juice supplementation on intermittent high-intensity exercise efforts

Beetroot juice contains high levels of inorganic nitrate (NO3-) and its intake has proved effective at increasing blood nitric oxide (NO) concentrations. Given the effects of NO in promoting vasodilation and blood flow with beneficial impacts on muscle contraction, several studies have detected an ergogenic effect of beetroot juice supplementation on exercise efforts with high oxidative energy metabolism demands. However, only a scarce yet growing number of investigations have sought to assess the effects of this supplement on performance at high-intensity exercise. Here we review the few studies that have addressed this issue. The databases Dialnet, Elsevier, Medline, Pubmed and Web of Science were searched for articles in English, Portuguese and Spanish published from 2010 to March 31 to 2017 using the keywords: beet or beetroot or nitrate or nitrite and supplement or supplementation or nutrition or "sport nutrition" and exercise or sport or "physical activity" or effort or athlete. Nine articles fulfilling the inclusion criteria were identified. Results indicate that beetroot juice given as a single dose or over a few days may improve performance at intermittent, high-intensity efforts with short rest periods. The improvements observed were attributed to faster phosphocreatine resynthesis which could delay its depletion during repetitive exercise efforts. In addition, beetroot juice supplementation could improve muscle power output via a mechanism involving a faster muscle shortening velocity. The findings of some studies also suggested improved indicators of muscular fatigue, though the mechanism involved in this effect remains unclear.

Metabolism and Whole-Body Fat Oxidation Following Postexercise Carbohydrate or Protein Intake

Purpose: This study investigated how postexercise intake of placebo (PLA), protein (PRO), or carbohydrate (CHO) affected fat oxidation (FO) and metabolic parameters during recovery and subsequent exercise. Methods: In a cross-over design, 12 moderately trained women (VO2max 45 ± 6 ml·min−1·kg−1) performed three days of testing. A 23-min control (CON) incremental FO bike test (30–80% VO2max) was followed by 60 min exercise at 75% VO2max. Immediately postexercise, subjects ingested PLA, 20 g PRO, or 40 g CHO followed by a second FO bike test 2 h later. Results: Maximal fat oxidation (MFO) and the intensity at which MFO occurs (Fatmax) increased at the second FO test compared to the first following all three postexercise drinks (MFO for CON = 0.28 ± 0.08, PLA = 0.57 ± 0.13, PRO = 0.52 ± 0.08, CHO = 0.44 ± 0.12 g fat·min−1; Fatmax for CON = 41 ± 7, PLA = 54 ± 4, PRO = 55 ± 6, CHO = 50 ± 8 %VO2max, p < 0.01 for all values compared to CON). Resting FO, MFO, and Fatmax were not significantly different between PLA and PRO, but lower for CHO. PRO and CHO increased insulin levels at 1 h postexercise, though both glucose and insulin were equal with PLA at 2 h postexercise. Increased postexercise ketone levels only occurred with PLA. Conclusion: Protein supplementation immediately postexercise did not affect the doubling in whole body fat oxidation seen during a subsequent exercise trial 2 h later. Neither did it affect resting fat oxidation during the postexercise period despite increased insulin levels and attenuated ketosis. Carbohydrate intake dampened the increase in fat oxidation during the second test, though a significant increase was still observed compared to the first test.

Recent developments on the extraction and application of ursolic acid. A review

Ursolic acid (UA) is a pentacyclic triterpenoid widely found in herbs, leaves, flowers and fruits; update information on the major natural sources or agro-industrial wastes is presented. Traditional (maceration, Soxhlet and heat reflux) and modern (microwave-, ultrasound-, accelerated solvent- and supercritical fluid) extraction and purification technologies of UA, as well as some patented process, are summarized. The great interest in this bioactive compound is related to the beneficial effects in human health due to antioxidant, antimicrobial, anti-inflammatory, hepatoprotective, immunomodulatory, anti-tumor, chemopreventive, cardioprotective, antihyperlipidemic and hypoglycemic activities, and others. UA may augment the resistance of the skin barrier to irritants, prevent dry skin and could be suitable to develop antiaging products. The development of nanocrystals and nanoparticle-based drugs could reduce the side effects of high doses of UA in organisms, and increase its limited solubility and poor bioavailability of UA which limit the potential of this bioactive and the further applications. Commercial patented applications in relation to cosmetical and pharmaceutical uses of UA and its derivatives are surveyed.

Nutritional needs in the professional practice of swimming: a review

[Purpose]

Swimming requires developing a high aerobic and anaerobic capacity for strength and technical efficiency. The purpose of this study was to establish the nutritional requirements and dietary strategies that can optimize swimming performance.

[Methods]

Several related studies retrieved from the databases, Dialnet, Elsevier, Medline, Pubmed, and Web of Science, through keyword search strategies were reviewed.

[Results]

The recommended carbohydrate intake ranges between 6-10-12 g/kg/d, protein 2 g/kg/d, and fat should surpass 20-25% of the daily intake.

[Conclusion]

Performance can be optimized with a hydration plan, as well as adequate periodization of supplements, such as caffeine, creatine, sodium bicarbonate, B-alanine, beetroot juice, Vitamin D, bovine colostrum, and HMB.

Creatine supplementation elicits greater muscle hypertrophy in upper than lower limbs and trunk in resistance-trained men

BACKGROUND

Creatine (Cr) supplementation associated with resistance training produces greater muscular strength improvements in the upper compared with the lower body; however, no study has investigated if such region-specific results are seen with gains in muscle mass.

AIM

We aimed to evaluate the effect of Cr supplementation in combination with resistance training on lean soft tissue changes in the upper and lower limbs and trunk in resistance-trained young adult men.

METHODS

In a randomized, double-blind and placebo-controlled design, 43 resistance-trained men (22.7 ± 3.0 years, 72.9 ± 8.7 kg, 177.9 ± 5.7 cm, 23.0 ± 2.5 kg/m²) received either creatine (Cr, n = 22) or placebo (PLA, n = 21) over an 8-week study period. The supplementation protocol included a loading phase (7 days, four doses of 0.3 g/kg per day) and a maintenance phase (7 weeks, single dose of 0.03 g/kg per day). During the same period, subjects performed resistance training four times per week using the following two-way split routine: Monday and Thursday = pectoral, shoulders, triceps, and abdomen, Tuesday and Friday = back, biceps, thighs, and calves. Lean soft tissue of the upper limbs (ULLST), lower limbs (LLLST), and trunk (TLST) was assessed by dual-energy X-ray absorptiometry before and after the intervention.

RESULTS

Both groups showed significant ( p < 0.001) improvements in ULLST, LLLST, TLST, and the Cr group achieved greater ( p < 0.001) increases in these outcomes compared with PLA. For the Cr group, improvements in ULLST (7.1 ± 2.9%) were higher than those observed in LLLST (3.2 ± 2.1%) and TLST (2.1 ± 2.2%). Otherwise, for PLA group there was no significant difference in the magnitude of segmental muscle hypertrophy (ULLST = 1.6 ± 3.0%; LLLST = 0.7 ± 2.8%; TLST = 0.7 ± 2.8%).

CONCLUSION

Our results suggest that Cr supplementation can positively augment muscle hypertrophy in resistance-trained young adult men, particularly in the upper limbs.

Creatine Use in Sports

Context:

The use of creatine as a dietary supplement has become increasingly popular over the past several decades. Despite the popularity of creatine, questions remain with regard to dosing, effects on sports performance, and safety.

Evidence Acquisition:

PubMed was searched for articles published between 1980 and January 2017 using the terms creatine, creatine supplementation, sports performance, and dietary supplements. An additional Google search was performed to capture National Collegiate Athletic Association–specific creatine usage data and US dietary supplement and creatine sales.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

Short-term use of creatine is considered safe and without significant adverse effects, although caution should be advised as the number of long-term studies is limited. Suggested dosing is variable, with many different regimens showing benefits. The safety of creatine supplementation has not been studied in children and adolescents. Currently, the scientific literature best supports creatine supplementation for increased performance in short-duration, maximal-intensity resistance training.

Conclusion:

While creatine appears to be safe and effective for particular settings, whether creatine supplementation leads to improved performance on the field of play remains unknown.

Short-Term Effects of a Ready-to-Drink Pre-Workout Beverage on Exercise Performance and Recovery

In a double-blind, randomized and crossover manner, 25 resistance-trained participants ingested a placebo (PLA) beverage containing 12 g of dextrose and a beverage (RTD) containing caffeine (200 mg), β-alanine (2.1 g), arginine nitrate (1.3 g), niacin (65 mg), folic acid (325 mcg), and Vitamin B12 (45 mcg) for 7-days, separated by a 7-10-day. On day 1 and 6, participants donated a fasting blood sample and completed a side-effects questionnaire (SEQ), hemodynamic challenge test, 1-RM and muscular endurance tests (3 × 10 repetitions at 70% of 1-RM with the last set to failure on the bench press (BP) and leg press (LP)) followed by ingesting the assigned beverage. After 15 min, participants repeated the hemodynamic test, 1-RM tests, and performed a repetition to fatigue (RtF) test at 70% of 1-RM, followed by completing the SEQ. On day 2 and 7, participants donated a fasting blood sample, completed the SEQ, ingested the assigned beverage, rested 30 min, and performed a 4 km cycling time-trial (TT). Data were analyzed by univariate, multivariate, and repeated measures general linear models (GLM), adjusted for gender and relative caffeine intake. Data are presented as mean change (95% CI). An overall multivariate time × treatment interaction was observed on strength performance variables (p = 0.01). Acute RTD ingestion better maintained LP 1-RM (PLA: -0.285 (-0.49, -0.08); RTD: 0.23 (-0.50, 0.18) kg/kg_FFM, p = 0.30); increased LP RtF (PLA: -2.60 (-6.8, 1.6); RTD: 4.00 (-0.2, 8.2) repetitions, p = 0.031); increased BP lifting volume (PLA: 0.001 (-0.13, 0.16); RTD: 0.03 (0.02, 0.04) kg/kg_FFM, p = 0.007); and, increased total lifting volume (PLA: -13.12 (-36.9, 10.5); RTD: 21.06 (-2.7, 44.8) kg/kg_FFM, p = 0.046). Short-term RTD ingestion maintained baseline LP 1-RM (PLA: -0.412 (-0.08, -0.07); RTD: 0.16 (-0.50, 0.18) kg/kg_FFM, p = 0.30); LP RtF (PLA: 0.12 (-3.0, 3.2); RTD: 3.6 (0.5, 6.7) repetitions, p = 0.116); and, LP lifting volume (PLA: 3.64 (-8.8, 16.1); RTD: 16.25 (3.8, 28.7) kg/kg_FFM, p = 0.157) to a greater degree than PLA. No significant differences were observed between treatments in cycling TT performance, hemodynamic assessment, fasting blood panels, or self-reported side effects.

Exercise redox biochemistry: Conceptual, methodological and technical recommendations

Exercise redox biochemistry is of considerable interest owing to its translational value in health and disease. However, unaddressed conceptual, methodological and technical issues complicate attempts to unravel how exercise alters redox homeostasis in health and disease. Conceptual issues relate to misunderstandings that arise when the chemical heterogeneity of redox biology is disregarded: which often complicates attempts to use redox-active compounds and assess redox signalling. Further, that oxidised macromolecule adduct levels reflect formation and repair is seldom considered. Methodological and technical issues relate to the use of out-dated assays and/or inappropriate sample preparation techniques that confound biochemical redox analysis. After considering each of the aforementioned issues, we outline how each issue can be resolved and provide a unifying set of recommendations. We specifically recommend that investigators: consider chemical heterogeneity, use redox-active compounds judiciously, abandon flawed assays, carefully prepare samples and assay buffers, consider repair/metabolism, use multiple biomarkers to assess oxidative damage and redox signalling.

Untargeted metabolomics of fresh and heat treatment Tiger nut (Cyperus esculentus L.) milks reveals further insight into food quality and nutrition

Tiger nut (Cyperus esculentus L.) is a crop traditionally grown in Valencia Region (Spain) and other temperate and tropical regions in the world, where its tubers are commonly consumed as tiger nut milk (horchata). Because of their nutritive potential and original taste, these products are beginning to spread internationally and, as consequence, analytical procedures to assess nutritional profiles, quality control issues are acquiring increasing relevance. The main objective of this study was to use an advance analytical method and chemometrics tools to determine if the ultra-high temperature (UHT) treatment necessary to extend the shelf life of tiger nut milk would affect the profile of nutrients when compared to fresh product. A cold solvent extraction followed by liquid chromatography coupled with high resolution mass spectrometry (UHPLC-HRMS) was used. Datasets obtained from UHT and fresh tiger nut milk data were analyzed through an untargeted metabolomics approach to compare chemical patterns, highlighting differences in citric acid esters of mono- diglycerides (CITREM) and monoacylglycerol (MAG) used as emulsifiers of UHT products, and a remarkably higher abundance of biotin, phosphatidic acid (PA) and L-arginine in fresh products. These results showed that untargeted metabolomics through high resolution tandem mass spectrometry allowed fine differences between food products to be found, therefore, the nutrient lost caused by UHT treatment was clearly discerned.

Ursolic acid induces mitochondrial biogenesis through the activation of AMPK and PGC-1 in C2C12 myotubes: a possible mechanism underlying its beneficial effect on exercise endurance

Mitochondrial biogenesis, which involves an increase in mitochondrial number and the overall capacity of oxidative phosphorylation, is a critical determinant of skeletal muscle function. Recent findings have shown that some natural products can enhance mitochondrial adaptation to aerobic exercise, which in turn improves exercise performance, presumably by delaying muscle fatigue. Ursolic acid (UA), a natural triterpene, is commonly found in various vegetables and fruits. In the current study, UA was shown to increase mitochondrial mass and ATP generation capacity, with a concomitant production of a low level of mitochondrial reactive oxygen species (ROS) in C2C12 myotubes. Mitochondrial ROS, in turn, activated the redox sensitive adenosine monophosphate-dependent protein kinase (AMPK)/peroxisome proliferator-activated receptor γ coactivator-1(PGC-1) pathway. The activation of AMPK/PGC-1 further increased the expression of cytochrome c oxidase (COX) and uncoupling protein 3. Animal studies showed that UA can also dose-dependently increase the endurance exercise capacity in mice, as assessed by a weight-loaded swimming test and a hanging wire test. Our findings suggest that UA may induce mitochondrial biogenesis through the activation of AMPK and PGC-1 pathways in skeletal muscle, thereby offering a promising prospect for its use to enhance exercise endurance and alleviating fatigue in humans.

Cognitive Performance Enhancement Induced by Caffeine, Carbohydrate and Guarana Mouth Rinsing during Submaximal Exercise

The aim of this study was to investigate the influence of serial mouth rinsing (MR) with nutritional supplements on cognitive performance (i.e., cognitive control and time perception) during a 40-min submaximal exercise. Twenty-four participants completed 4 counterbalanced experimental sessions, during which they performed MR with either placebo (PL), carbohydrate (CHO: 1.6 g/25 mL), guarana complex (GUAc: 0.4 g/25 mL) or caffeine (CAF: 67 mg/25 mL) before and twice during exercise. The present study provided some important new insights regarding the specific changes in cognitive performance induced by nutritional supplements. The main results were: (1) CHO, CAF and GUA MR likely led participants to improve temporal performance; (2) CAF MR likely improved cognitive control; and (3) CHO MR led to a likely decrease in subjective perception of effort at the end of the exercise compared to PL, GUA and CAF. Moreover, results have shown that performing 40-min submaximal exercise enhances information processing in terms of both speed and accuracy, improves temporal performance and does not alter cognitive control. The present study opens up new perspectives regarding the use of MR to optimize cognitive performance during physical exercise.

"Nutraceuticals" in relation to human skeletal muscle and exercise

Skeletal muscles have a fundamental role in locomotion and whole body metabolism, with muscle mass and quality being linked to improved health and even lifespan. Optimizing nutrition in combination with exercise is considered an established, effective ergogenic practice for athletic performance. Importantly, exercise and nutritional approaches also remain arguably the most effective countermeasure for muscle dysfunction associated with aging and numerous clinical conditions, e.g., cancer cachexia, COPD, and organ failure, via engendering favorable adaptations such as increased muscle mass and oxidative capacity. Therefore, it is important to consider the effects of established and novel effectors of muscle mass, function, and metabolism in relation to nutrition and exercise. To address this gap, in this review, we detail existing evidence surrounding the efficacy of a nonexhaustive list of macronutrient, micronutrient, and "nutraceutical" compounds alone and in combination with exercise in relation to skeletal muscle mass, metabolism (protein and fuel), and exercise performance (i.e., strength and endurance capacity). It has long been established that macronutrients have specific roles and impact upon protein metabolism and exercise performance, (i.e., protein positively influences muscle mass and protein metabolism), whereas carbohydrate and fat intakes can influence fuel metabolism and exercise performance. Regarding novel nutraceuticals, we show that the following ones in particular may have effects in relation to 1) muscle mass/protein metabolism: leucine, hydroxyl β-methylbutyrate, creatine, vitamin-D, ursolic acid, and phosphatidic acid; and 2) exercise performance: (i.e., strength or endurance capacity): hydroxyl β-methylbutyrate, carnitine, creatine, nitrates, and β-alanine.

Periodized Nutrition for Athletes

It is becoming increasingly clear that adaptations, initiated by exercise, can be amplified or reduced by nutrition. Various methods have been discussed to optimize training adaptations and some of these methods have been subject to extensive study. To date, most methods have focused on skeletal muscle, but it is important to note that training effects also include adaptations in other tissues (e.g., brain, vasculature), improvements in the absorptive capacity of the intestine, increases in tolerance to dehydration, and other effects that have received less attention in the literature. The purpose of this review is to define the concept of periodized nutrition (also referred to as nutritional training) and summarize the wide variety of methods available to athletes. The reader is referred to several other recent review articles that have discussed aspects of periodized nutrition in much more detail with primarily a focus on adaptations in the muscle. The purpose of this review is not to discuss the literature in great detail but to clearly define the concept and to give a complete overview of the methods available, with an emphasis on adaptations that are not in the muscle. Whilst there is good evidence for some methods, other proposed methods are mere theories that remain to be tested. 'Periodized nutrition' refers to the strategic combined use of exercise training and nutrition, or nutrition only, with the overall aim to obtain adaptations that support exercise performance. The term nutritional training is sometimes used to describe the same methods and these terms can be used interchangeably. In this review, an overview is given of some of the most common methods of periodized nutrition including 'training low' and 'training high', and training with low- and high-carbohydrate availability, respectively. 'Training low' in particular has received considerable attention and several variations of 'train low' have been proposed. 'Training-low' studies have generally shown beneficial effects in terms of signaling and transcription, but to date, few studies have been able to show any effects on performance. In addition to 'train low' and 'train high', methods have been developed to 'train the gut', train hypohydrated (to reduce the negative effects of dehydration), and train with various supplements that may increase the training adaptations longer term. Which of these methods should be used depends on the specific goals of the individual and there is no method (or diet) that will address all needs of an individual in all situations. Therefore, appropriate practical application lies in the optimal combination of different nutritional training methods. Some of these methods have already found their way into training practices of athletes, even though evidence for their efficacy is sometimes scarce at best. Many pragmatic questions remain unanswered and another goal of this review is to identify some of the remaining questions that may have great practical relevance and should be the focus of future research.

Effects of Beetroot Juice Supplementation on Cardiorespiratory Endurance in Athletes. A Systematic Review

Athletes use nutritional supplementation to enhance the effects of training and achieve improvements in their athletic performance. Beetroot juice increases levels of nitric oxide (NO), which serves multiple functions related to increased blood flow, gas exchange, mitochondrial biogenesis and efficiency, and strengthening of muscle contraction. These biomarker improvements indicate that supplementation with beetroot juice could have ergogenic effects on cardiorespiratory endurance that would benefit athletic performance. The aim of this literature review was to determine the effects of beetroot juice supplementation and the combination of beetroot juice with other supplements on cardiorespiratory endurance in athletes. A keyword search of DialNet, MedLine, PubMed, Scopus and Web of Science databases covered publications from 2010 to 2016. After excluding reviews/meta-analyses, animal studies, inaccessible full-text, and studies that did not supplement with beetroot juice and adequately assess cardiorespiratory endurance, 23 articles were selected for analysis. The available results suggest that supplementation with beetroot juice can improve cardiorespiratory endurance in athletes by increasing efficiency, which improves performance at various distances, increases time to exhaustion at submaximal intensities, and may improve the cardiorespiratory performance at anaerobic threshold intensities and maximum oxygen uptake (VO_2max). Although the literature shows contradictory data, the findings of other studies lead us to hypothesize that supplementing with beetroot juice could mitigate the ergolytic effects of hypoxia on cardiorespiratory endurance in athletes. It cannot be stated that the combination of beetroot juice with other supplements has a positive or negative effect on cardiorespiratory endurance, but it is possible that the effects of supplementation with beetroot juice can be undermined by interaction with other supplements such as caffeine.

The NAD(+) precursor nicotinamide riboside decreases exercise performance in rats

BACKGROUND

Nicotinamide adenine dinucleotide (NAD(+)) and its phosphorylated form (NADP(+)) are key molecules in ubiquitous bioenergetic and cellular signaling pathways, regulating cellular metabolism and homeostasis. Thus, supplementation with NAD(+) and NADP(+) precursors emerged as a promising strategy to gain many and multifaceted health benefits. In this proof-of-concept study, we sought to investigate whether chronic nicotinamide riboside administration (an NAD(+) precursor) affects exercise performance.

METHODS

Eighteen Wistar rats were equally divided in two groups that received either saline vehicle or nicotinamide riboside at a dose of 300 mg/kg body weight/day for 21 days via gavage. At the end of the 21-day administration protocol, both groups performed an incremental swimming performance test.

RESULTS

The nicotinamide riboside group showed a tendency towards worse physical performance by 35 % compared to the control group at the final 10 % load (94 ± 53 s for the nicotinamide riboside group and 145 ± 59 s for the control group; P = 0.071).

CONCLUSION

Our results do not confirm the previously reported ergogenic effect of nicotinamide riboside. The potentially negative effect of nicotinamide riboside administration on physical performance may be attributed to the pleiotropic metabolic and redox properties of NAD(+) and NADP(+).