Effect of slow-release β-alanine tablets on absorption kinetics and paresthesia

Effects of β-Alanine Supplementation on Subjects Performing High-Intensity Functional Training

BACKGROUND

β-alanine, a non-essential amino acid found in the diet and produced through nucleotide catabolism, is significant for muscle performance due to its role in carnosine synthesis. This study aims to assess the impact of a 4-week β-alanine supplementation on neuromuscular fatigue in individuals engaging in High-Intensity Functional Training (HIFT) and its subsequent effect on sports performance, distinguishing between central fatigue from the CNS and peripheral fatigue from the muscular system.

MATERIALS AND METHODS

This study (a randomized controlled trial) comprised a total of 27 subjects, who were divided into two groups. Group A (the control group) was administered sucrose powder, while Group B (the experimental group) was given β-alanine powder. The subjects were randomly assigned to either the experimental or control groups. This study lasted four weeks, during which both groups participated in high-intensity interval training (HIFT) on the first day to induce fatigue and work close to their VO2 max.

RESULTS

Statistically significant changes were in the sports performance variables, specifically vertical jump and jumping power (p = 0.027). These changes were observed only in the group that had been supplemented with β-alanine. Nevertheless, no alterations were observed in any other variables, including fatigue, metabolic intensity of exercise, or perceived intensity (p > 0.05).

CONCLUSIONS

A four-week β-alanine intake program demonstrated an improvement in the capacity of subjects, as evidenced by enhanced vertical jump and power performance. Nevertheless, it does result in discernible alterations in performance.

The Mas-related G protein-coupled receptor d (Mrgprd) mediates pain hypersensitivity in painful diabetic neuropathy

ABSTRACT

Painful diabetic neuropathy (PDN) is one of the most common and intractable complications of diabetes. Painful diabetic neuropathy is characterized by neuropathic pain accompanied by dorsal root ganglion (DRG) nociceptor hyperexcitability, axonal degeneration, and changes in cutaneous innervation. However, the complete molecular profile underlying the hyperexcitable cellular phenotype of DRG nociceptors in PDN has not been elucidated. This gap in our knowledge is a critical barrier to developing effective, mechanism-based, and disease-modifying therapeutic approaches that are urgently needed to relieve the symptoms of PDN. Using single-cell RNA sequencing of DRGs, we demonstrated an increased expression of the Mas-related G protein-coupled receptor d (Mrgprd) in a subpopulation of DRG neurons in the well-established high-fat diet (HFD) mouse model of PDN. Importantly, limiting Mrgprd signaling reversed mechanical allodynia in the HFD mouse model of PDN. Furthermore, in vivo calcium imaging allowed us to demonstrate that activation of Mrgprd-positive cutaneous afferents that persist in diabetic mice skin resulted in an increased intracellular calcium influx into DRG nociceptors that we assess in vivo as a readout of nociceptors hyperexcitability. Taken together, our data highlight a key role of Mrgprd-mediated DRG neuron excitability in the generation and maintenance of neuropathic pain in a mouse model of PDN. Hence, we propose Mrgprd as a promising and accessible target for developing effective therapeutics currently unavailable for treating neuropathic pain in PDN.

Food for thought: Physiological considerations for nutritional ergogenic efficacy

Top-class athletes have optimized their athletic performance largely through adequate training, nutrition, recovery, and sleep. A key component of sports nutrition is the utilization of nutritional ergogenic aids, which may provide a small but significant increase in athletic performance. Over the last decade, there has been an exponential increase in the consumption of nutritional ergogenic aids, where over 80% of young athletes report using at least one nutritional ergogenic aid for training and/or competition. Accordingly, due to their extensive use, there is a growing need for strong scientific investigations validating or invalidating the efficacy of novel nutritional ergogenic aids. Notably, an overview of the physiological considerations that play key roles in determining ergogenic efficacy is currently lacking. Therefore, in this brief review, we discuss important physiological considerations that contribute to ergogenic efficacy for nutritional ergogenic aids that are orally ingested including (1) the impact of first pass metabolism, (2) rises in systemic concentrations, and (3) interactions with the target tissue. In addition, we explore mouth rinsing as an alternate route of ergogenic efficacy that bypasses the physiological hurdles of first pass metabolism via direct stimulation of the central nervous system. Moreover, we provide real-world examples and discuss several practical factors that can alter the efficacy of nutritional ergogenic aids including human variability, dosing protocols, training status, sex differences, and the placebo effect. Taking these physiological considerations into account will strengthen the quality and impact of the literature regarding the efficacy of potential ergogenic aids for top-class athletes.

Use of Buffers in Specific Contexts: Highly Trained Female Athletes, Extreme Environments and Combined Buffering Agents-A Narrative Review

This narrative review evaluated the evidence for buffering agents (sodium bicarbonate, sodium citrate and beta-alanine), with specific consideration of three discrete scenarios: female athletes, extreme environments and combined buffering agents. Studies were screened according to exclusion and inclusion criteria and were analysed on three levels: (1) moderating variables (supplement dose and timing, and exercise test duration and intensity), (2) design factors (e.g., use of crossover or matched group study design, familiarisation trials) and (3) athlete-specific factors (recruitment of highly trained participants, buffering capacity and reported performance improvements). Only 19% of the included studies for the three buffering agents reported a performance benefit, and only 10% recruited highly trained athletes. This low transferability of research findings to athletes' real-world practices may be due to factors including the small number of sodium citrate studies in females (n = 2), no studies controlling for the menstrual cycle (MC) or menstrual status using methods described in recently established frameworks, and the limited number of beta-alanine studies using performance tests replicating real-world performance efforts (n = 3). We recommend further research into buffering agents in highly trained female athletes that control or account for the MC, studies that replicate the demands of athletes' heat and altitude camps, and investigations of highly trained athletes' use of combined buffering agents. In a practical context, we recommend developing evidence-based buffering protocols for individual athletes which feature co-supplementation with other evidence-based products, reduce the likelihood of side-effects, and optimise key moderating factors: supplement dose and timing, and exercise duration and intensity.

The Anti-Cancer Activity of the Naturally Occurring Dipeptide Carnosine: Potential for Breast Cancer

Carnosine is an endogenous dipeptide composed of β-alanine and L-histidine, possessing a multimodal pharmacodynamic profile that includes anti-inflammatory and anti-oxidant activities. Carnosine has also shown its ability to modulate cell proliferation, cell cycle arrest, apoptosis, and even glycolytic energy metabolism, all processes playing a key role in the context of cancer. Cancer is one of the most dreaded diseases of the 20th and 21st centuries. Among the different types of cancer, breast cancer represents the most common non-skin cancer among women, accounting for an estimated 15% of all cancer-related deaths in women. The main aim of the present review was to provide an overview of studies on the anti-cancer activity of carnosine, and in particular its activity against breast cancer. We also highlighted the possible advantages and limitations involved in the use of this dipeptide. The first part of the review entailed a brief description of carnosine's biological activities and the pathophysiology of cancer, with a focus on breast cancer. The second part of the review described the anti-tumoral activity of carnosine, for which numerous studies have been carried out, especially at the preclinical level, showing promising results. However, only a few studies have investigated the therapeutic potential of this dipeptide for breast cancer prevention or treatment. In this context, carnosine has shown to be able to decrease the size of cancer cells and their viability. It also reduces the levels of vascular endothelial growth factor (VEGF), cyclin D1, NAD+, and ATP, as well as cytochrome c oxidase activity in vitro. When tested in mice with induced breast cancer, carnosine proved to be non-toxic to healthy cells and exhibited chemopreventive activity by reducing tumor growth. Some evidence has also been reported at the clinical level. A randomized phase III prospective placebo-controlled trial showed the ability of Zn-carnosine to prevent dysphagia in breast cancer patients undergoing adjuvant radiotherapy. Despite this evidence, more preclinical and clinical studies are needed to better understand carnosine's anti-tumoral activity, especially in the context of breast cancer.

Effect of a sustained-release formulation of β-alanine on laboratory parameters and paresthesia in recreational trained men: a randomized double-blind placebo-controlled study

Introduction

Beta-alanine is a non-essential amino acid that has been a focus of increasing research by its role as ergogenic aid to improve muscle performance.

Methods

A randomized, double-blind and controlled trial was conducted to determine the effect of a nutritional supplement of a sustained-release formulation of β-alanine in recreational trained men. The active product was an innovative sustained-release β-alanine microgranules powder blend, administered at high doses (15 g/day) divided into 3 intakes during 30 days. There were 10 participants in the experimental group and 9 in the placebo group, with a mean age of 22.5 ± 3.3 years. Participants were testing at baseline and at the end of study.

Results

In the β-alanine group, there were statistically increases in serum triglycerides, LDL-cholesterol, and urea nitrogen at the end of the study as compared with baseline, although there were no differences with the control group. The occurrence of paresthesia, described above all as tickling, was the majority but presented VAS score less than 3/10 in almost all subjects.

Discussion

More studies are required to evaluate the changes in blood parameters that can be caused by high intake of β-alanine during a long period of time.

Clinical trial registration

ClinicalTrials.gov, identifier (NCT05334121).

β-Alanine Supplementation in Combat Sports: Evaluation of Sports Performance, Perception, and Anthropometric Parameters and Biochemical Markers-A Systematic Review of Clinical Trials

β-alanine does not have an ergogenic effect by itself, but it does as a precursor for the synthesis of carnosine in human skeletal muscle. β-alanine and carnosine together help improve the muscles' functionality, especially in high-intensity exercises such as combat sports. Therefore, β-alanine could be considered a nutritional ergogenic aid to improve sports performance in combat athletes. We aimed to critically review clinical trial evidence on the impact of β-alanine supplementation on sports performance, perception, and anthropometric parameters, as well as circulating biochemical markers in combat athletes. This systematic review was conducted following the specific methodological guidelines of the Preferred Report Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA), the PICOS question model, the Critical Review Form of McMaster, and the PEDro scale. Furthermore, the Cochrane risk-of-bias assessment tool was used. The search was carried out in the SCOPUS, Web of Science (WOS), and Medline (PubMed) databases for studies published from the beginning of the database until July 31, 2023. Of the 41 registers identified, only 7 met the established criteria and were included in this systematic review. Overall, performance parameters related to strength, power, total exercise work capacity, and combat-specific parameters were significantly improved (p < 0.05). Perception parameters increased non-significantly (p > 0.05). Regarding biochemical parameters, carnosine increased significantly (p < 0.05), pH decreased non-significantly (p > 0.05), and the results for blood bicarbonate and blood lactate were heterogeneous. Finally, there was a non-significant (p > 0.05) improvement in the anthropometric parameters of lean mass and fat mass. β-alanine supplementation appears to be safe and could be a suitable nutritional ergogenic aid for combat athletes.

Acute Supplementation with Beta-Alanine Improves Performance in Aerobic-Anaerobic Transition Zones in Endurance Athletes

To determine the acute effect of low and high-dose BA trials on maximal aerobic speed (MAS) in endurance athletes. We hypothesized that high doses of BA have a greater effect than low doses, both compared to baseline.

Twelve male endurance athletes volunteered for the study (age = 21.8 ± 2.37 years, weight = 69.8 ± 4.36 kg, height = 174 ± 5.45 cm, maximal oxygen uptake = 59.6 ± 3.77 mLO₂·kg^-1·min^-1). The experimental design applied was randomized cross-over, double-blind. Treatment included three 6-minute run tests (6-MRT), the first as a baseline, then randomized 6-MRT with low (30 mg·kg^-1) and high (45 mg·kg^-1) dose BA trials. The 6-MRTs were separated by 72 hours. The main variable of the study was the distance (m) performed in the 6-MRT. Differences between tests were established through ANOVA and Tukey's multiple comparison tests (p < 0.05).

The analysis showed significant differences between baseline and both doses (p < 0.001). No significant differences were observed between low and high-dose BA trials (p > 0.05).

Both 30 and 45 mg·kg^-1 of BA increased physical performance at maximal aerobic speed in endurance athletes. The acute intake formats described in the present investigation may be helpful for endurance athletes training and competing in aerobic-anaerobic transition zones.

Carnosine as a potential therapeutic for the management of peripheral vascular disease

AIMS

To evaluate the potential role of carnosine in the management of peripheral vascular disease.

DATA SYNTHESIS

Peripheral vascular disease is growing in its burden and impact; however it is currently under researched, and there are a lack of strong, non-invasive therapeutic options for the clinicians. Carnosine is a dipeptide stored particularly in muscle and brain tissue, which exhibits a wide range of physiological activities, which may be beneficial as an adjunct treatment for peripheral vascular disease. Carnosine's strong anti-inflammatory, antioxidant and antiglycating actions may aid in the prevention of plaque formation, through protective actions on the vascular endothelium, and the inhibition of foam cells. Carnosine may also improve angiogenesis, exercise performance and vasodilatory response, while protecting from ischemic tissue injury.

CONCLUSIONS

Carnosine may have a role as an adjunct treatment for peripheral vascular disease alongside typical exercise and surgical interventions, and may be used in high risk individuals to aid in the prevention of atherogenesis.

CLINICAL RECOMMENDATION

This review identifies a beneficial role for carnosine supplementation in the management of patients with peripheral vascular disease, in conjunction with exercise and revascularization. Carnosine as a supplement is safe, and associated with a host of beneficial effects in peripheral vascular disease and its key risk factors.

Efficacy of 12 weeks oral beta-alanine supplementation in patients with chronic obstructive pulmonary disease: a double-blind, randomized, placebo-controlled trial

BACKGROUND

Beta-alanine (BA) supplementation increases muscle carnosine, an abundant endogenous antioxidant and pH buffer in skeletal muscle. Carnosine loading promotes exercise capacity in healthy older adults. As patients with chronic obstructive pulmonary disease (COPD) suffer from elevated exercise-induced muscle oxidative/carbonyl stress and acidosis, and from reduced muscle carnosine stores, it was investigated whether BA supplementation augments muscle carnosine and induces beneficial changes in exercise capacity, quadriceps function, and muscle oxidative/carbonyl stress in patients with COPD.

METHODS

In this double-blind, randomized, placebo (PL)-controlled trial (clinicaltrials.gov identifier: NCT02770417), 40 patients (75% male) with COPD (mean ± standard deviation: age 65 ± 6 years; FEV₁ % predicted 55 ± 14%) were assigned to 12 weeks oral BA or PL supplementation (3.2 g/day). The primary outcome, i.e. muscle carnosine, was quantified from m. vastus lateralis biopsies obtained before and after intervention. Co-primary outcomes, i.e. incremental and constant work rate cycle capacity, were also assessed. Linear mixed model analyses were performed. Compliance with and side effects of supplement intake and secondary outcomes (quadriceps strength and endurance, and muscle oxidative/carbonyl stress) were also assessed.

RESULTS

Beta-alanine supplementation increased muscle carnosine in comparison with PL in patients with COPD (mean difference [95% confidence interval]; +2.82 [1.49-4.14] mmol/kg wet weight; P < 0.001). Maximal incremental cycling capacity (VO₂ peak: +0.5 [-0.7 to 1.7] mL/kg/min; P = 0.384, Wpeak: +5 [-1 to 11] W; P = 0.103) and time to exhaustion on the constant work rate cycle test (+28 [-179 to 236] s; P = 0.782) did not change significantly. Compliance with supplement intake was similar in BA (median (quartile 1-quartile 3); 100 (98-100)%) and PL (98 (96-100)%) (P = 0.294) groups, and patients did not report side effects possibly related to supplement intake. No change was observed in secondary outcomes.

CONCLUSIONS

Beta-alanine supplementation is efficacious in augmenting muscle carnosine (+54% from mean baseline value) without side effects in patients with COPD in comparison with PL. However, accompanied beneficial changes in exercise capacity, quadriceps function, and muscle oxidative/carbonyl stress were not observed.

The Therapeutic Potential of Carnosine as an Antidote against Drug-Induced Cardiotoxicity and Neurotoxicity: Focus on Nrf2 Pathway

Different drug classes such as antineoplastic drugs (anthracyclines, cyclophosphamide, 5-fluorouracil, taxanes, tyrosine kinase inhibitors), antiretroviral drugs, antipsychotic, and immunosuppressant drugs are known to induce cardiotoxic and neurotoxic effects. Recent studies have demonstrated that the impairment of the nuclear factor erythroid 2–related factor 2 (Nrf2) pathway is a primary event in the pathophysiology of drug-induced cardiotoxicity and neurotoxicity. The Nrf2 pathway regulates the expression of different genes whose products are involved in antioxidant and inflammatory responses and the detoxification of toxic species. Cardiotoxic drugs, such as the anthracycline doxorubicin, or neurotoxic drugs, such as paclitaxel, suppress or impair the Nrf2 pathway, whereas the rescue of this pathway counteracts both the oxidative stress and inflammation that are related to drug-induced cardiotoxicity and neurotoxicity. Therefore Nrf2 represents a novel pharmacological target to develop new antidotes in the field of clinical toxicology. Interestingly, carnosine (β-alanyl-l-histidine), an endogenous dipeptide that is characterized by strong antioxidant, anti-inflammatory, and neuroprotective properties is able to rescue/activate the Nrf2 pathway, as demonstrated by different preclinical studies and preliminary clinical evidence. Starting from these new data, in the present review, we examined the evidence on the therapeutic potential of carnosine as an endogenous antidote that is able to rescue the Nrf2 pathway and then counteract drug-induced cardiotoxicity and neurotoxicity.

Exploring neuronal mechanisms involved in the scratching behavior of a mouse model of allergic contact dermatitis by transcriptomics

Background

Allergic contact dermatitis (ACD) is a common skin condition characterized by contact hypersensitivity to allergens, accompanied with skin inflammation and a mixed itch and pain sensation. The itch and pain dramatically affects patients’ quality of life. However, still little is known about the mechanisms triggering pain and itch sensations in ACD.

Methods

We established a mouse model of ACD by sensitization and repetitive challenge with the hapten oxazolone. Skin pathological analysis, transcriptome RNA sequencing (RNA-seq), qPCR, Ca²⁺ imaging, immunostaining, and behavioral assay were used for identifying gene expression changes in dorsal root ganglion innervating the inflamed skin of ACD model mice and for further functional validations.

Results

The model mice developed typical ACD symptoms, including skin dryness, erythema, excoriation, edema, epidermal hyperplasia, inflammatory cell infiltration, and scratching behavior, accompanied with development of eczematous lesions. Transcriptome RNA-seq revealed a number of differentially expressed genes (DEGs), including 1436-DEG mRNAs and 374-DEG-long noncoding RNAs (lncRNAs). We identified a number of DEGs specifically related to sensory neuron signal transduction, pain, itch, and neuroinflammation. Comparison of our dataset with another published dataset of atopic dermatitis mouse model identified a core set of genes in peripheral sensory neurons that are exclusively affected by local skin inflammation. We further found that the expression of the pain and itch receptor MrgprD was functionally upregulated in dorsal root ganglia (DRG) neurons innervating the inflamed skin of ACD model mice. MrgprD activation induced by its agonist β-alanine resulted in exaggerated scratching responses in ACD model mice compared with naïve mice.

Conclusions

We identified the molecular changes and cellular pathways in peripheral sensory ganglia during ACD that might participate in neurogenic inflammation, pain, and itch. We further revealed that the pain and itch receptor MrgprD is functionally upregulated in DRG neurons, which might contribute to peripheral pain and itch sensitization during ACD. Thus, targeting MrgprD may be an effective method for alleviating itch and pain in ACD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00316-w.

New Opportunities to Advance the Field of Sports Nutrition

Sports nutrition is a relatively new discipline; with ~100 published papers/year in the 1990s to ~3,500+ papers/year today. Historically, sports nutrition research was primarily initiated by university-based exercise physiologists who developed new methodologies that could be impacted by nutrition interventions (e.g., carbohydrate/fat oxidation by whole body calorimetry and muscle glycogen by muscle biopsies). Application of these methods in seminal studies helped develop current sports nutrition guidelines as compiled in several expert consensus statements. Despite this wealth of knowledge, a limitation of the current evidence is the lack of appropriate intervention studies (e.g., randomized controlled clinical trials) in elite athlete populations that are ecologically valid (e.g., in real-life training and competition settings). Over the last decade, there has been an explosion of sports science technologies, methodologies, and innovations. Some of these recent advances are field-based, thus, providing the opportunity to accelerate the application of ecologically valid personalized sports nutrition interventions. Conversely, the acceleration of novel technologies and commercial solutions, especially in the field of biotechnology and software/app development, has far outstripped the scientific communities' ability to validate the effectiveness and utility of the vast majority of these new commercial technologies. This mini-review will highlight historical and present innovations with particular focus on technological innovations in sports nutrition that are expected to advance the field into the future. Indeed, the development and sharing of more “big data,” integrating field-based measurements, resulting in more ecologically valid evidence for efficacy and personalized prescriptions, are all future key opportunities to further advance the field of sports nutrition.

Evaluation of spatial memory and anti-fatigue function of long-term supplementation of <i>β</i>-alanine and confirmation through cAMP-PKA and apoptosis pathways in mice

With an aim to explore the effects of <i>β</i>-alanine (<i>β</i>-A) on spatial memory and fatigue resistance, Kunming mice were treated with different concentrations of β-A (418, 836, and 2090 mg·kg^-1·day^-1). After gavage feeding with <i>β</i>-A for 10 weeks, results of the maze and MWM tests showed that <i>β</i>-A can enhance spatial learning and memory in mice. After evaluating the fatigue resistance, biochemical parameters (LG, GG, BUN, SOD, and MDA) showed significant differences in the low concentration treatment group compared to control group. Our data demonstrated that the appropriate dose of <i>β</i>-A can alleviate the oxidative stress and muscle fatigue in mice. Subsequently, expression of mRNA of key genes involved in cAMP-PKA pathway (PDE4A, MAPK1, adcy1, cAMP and CREB) was up regulated. Also, expression levels of apoptotic pathway genes were significantly affected as confirmed by qPCR and Western blotting. Our results demonstrated that <i>β</i>-A can enhance spatial learning and memory in mice via regulation of cAMP-PKA and apoptotic pathway.

Effect of β-alanine and sodium bicarbonate co-supplementation on the body's buffering capacity and sports performance: A systematic review

Muscle acidification is one of the main factors causing fatigue during exercise, thus compromising performance. The sport supplements beta alanine (β-A) and sodium bicarbonate (SB) are thought to enhance the effects of the body's buffer systems by reducing H⁺ concentrations. The aim of this systematic review was to analyze the effects of β-A and SB co-supplementation on the organism's buffering capacity and sport performance. The databases PubMed, Web of Science, Medline, CINAHL and SPORTDiscus were searched until November 2021 following PRISMA guidelines. Randomized controlled trials, at least single-blind, performed in athletes of any age were considered. Nine studies including a total of 221 athletes were identified for review. Athletes were supplemented with β-A and SB while they performed exercise tests to assess physical performance and buffer capacity. Five of the nine studies indicated there was some additional improvement in buffering capacity and performance with co-supplementation, while one study concluded that the effect was comparable to the added effects of the individual supplements. According to the results of the studies reviewed, we would recommend β-A and SB co-supplementation during high intensity exercises lasting between 30 s and 10 min.

Increased Bioavailability of β-Alanine by a Novel Controlled-Release Powder Blend Compared to a Slow-Release Tablet

BACKGROUND

β-Alanine is a sport supplement with increasing popularity due to its consistent ability to improve physical performance, with the downside of requiring several weeks of supplementation as imposed to the maximum daily and single dose tolerated without side effects (i.e., paresthesia). To date, the only alternative to overcome this problem has been use of a sustained-release tablet, while powders are the most commonly used format to deliver several grams of amino acids in a single dose. In this study we assessed the bioavailability, pharmacokinetics and paresthesia effect of β-alanine after administration in a novel controlled-released powder blend (test) versus a sustained-release tablet (reference).

METHODS

Twelve subjects (25.6 ± 3.2 y, 50% female) participated in a randomized, single-blind, crossover study. Each participant was administered orally the test (β-alanine 8 g, l-histidine 300 mg, carnosine 100 mg) or the reference product (10 tablets to reach β-alanine 8 g, Zinc 20 mg) with a 1-week washout period. β-Alanine plasma concentrations (0-8 h) were determined by LC-MS/MS and model-independent pharmacokinetic analysis was carried out. Paresthesia intensity was evaluated using a Visual Analog Score (VAS) and the categorical Intensity Sensory Score (ISS).

RESULTS

The CMAX and AUC0→∞ increased 1.6- and 2.1-fold (both p < 0.001) in the test product, respectively, which yielded 2.1-fold higher bioavailability; Ka decreased in the test (0.0199 ± 0.0107 min-1) versus the reference (0.0299 ± 0.0121 min-1) product (p = 0.0834) as well as V/F and Cl/F (both p < 0.001); MRT0→last increased in the test (143 ± 19 min) versus reference (128 ± 16 min) formulation (p = 0.0449); t1/2 remained similar (test: 63.5 ± 8.7 min, reference: 68.9 ± 9.8 min). Paresthesia EMAX increased 1.7-fold using the VAS (p = 0.086) and the ISS (p = 0.009). AUEC increased 1.9-fold with the VAS (p = 0.107) and the ISS (p = 0.019) reflecting scale intrinsic differences. Pharmacokinetic-pharmacodynamic analysis showed a clockwise hysteresis loop without prediction ability between CMAX, AUC0→∞ and EMAX or AUEC. No side effects were reported (except paresthesia).

CONCLUSIONS

The novel controlled-release powder blend shows 100% higher bioavailability of β-alanine, opening a new paradigm that shifts from chronic to short or mid-term supplementation strategies to increase carnosine stores in sports nutrition.

Effects of Acute Beta-Alanine Ingestion and Immersion-Plus-Exercise on Connectedness to Nature and Perceived Pain

This double-blinded, placebo-controlled, crossover study examined the effect of induced painful sensation (via acute Beta Alanine (B-ALA) ingestion) on Love and Care of Nature (LCN), heart rate (HR), rating of perceived exertion (RPE), and McGill Pain Questionnaire (MPQ) during outdoor exercise. Twenty participants volunteered on consecutive days to complete a 0.8 km (0.5 mi) up-hill hike after consuming either B-ALA (6.4 g) or placebo. Immediately after consumption participants answered LCN, RPE, and MPQ questionnaires, immersed in a natural environment for 45 min, and then completed a hike as quickly as possible without running. No difference in HR (p = 0.846), or RPE (p = 0.606) were observed between treatments. Total MPQ scores increased with consumption of B-ALA (p = 0.001). An increased LCN score was observed following exercise regardless of condition (p = 0.035). The results demonstrate that acute B-ALA supplementation is effective in increasing perceived pain sensations. The results also demonstrate an increase in LCN in the presence of increased perceptions of pain sensations during exercise.

Beta-alanine did not improve high-intensity performance throughout simulated road cycling

This study investigated the effect of beta-alanine supplementation on short-duration sprints and final 4-km simulated uphill cycling time-trial performance during a comprehensive and novel exercise protocol representative of the demands of road-race cycling, and determined if changes were related to increases in muscle carnosine content. Seventeen cyclists (age 38 ± 9 y, height 1.76 ± 0.07 m, body mass 71.4 ± 8.8 kg, V̇O_2max 52.4 ± 8.3 ml·kg^-1·min^-1) participated in this placebo-controlled, double-blind study. Cyclists undertook a prolonged intermittent cycling protocol lasting 125 min, with a 10-s sprint every 20 min, finishing with a 4-km time-trial at 5% simulated incline. Participants completed two familiarization sessions, and two main sessions, one pre-supplementation and one post-supplementation following 28 days of 6.4 g·day^-1 of beta-alanine (N=11) or placebo (N=6; maltodextrin). Muscle biopsies obtained pre- and post-supplementation were analysed for muscle carnosine content. There were no main effects on sprint performance throughout the intermittent cycling test (all P>0.05). There was no group (P=0.69), time (P=0.50) or group x time interaction (P=0.26) on time-to-complete the 4-km time-trial. Time-to-completion did not change from pre- to post-supplementation for BA (-19.2 ± 45.6 s, P=0.43) or PL (+2.8 ± 31.6 s, P=0.99). Beta-alanine supplementation increased muscle carnosine content from pre- to post-supplementation (+9.4 ± 4.0 mmol·kg^-1dm; P<0.0001) but was not related to performance changes (r=0.320, P=0.37). Chronic beta-alanine supplementation increased muscle carnosine content but did not improve short-duration sprint performance throughout simulated road race cycling, nor 4-km uphill time-trial performance conducted at the end of this cycling test.Highlights Performance during prolonged cycling events often depends on the ability to maintain an increased power output during higher intensity periods. Thus, cyclists are likely heavily dependent on their ability to resist fatigue during these periods of high-intensity activity.Meta-analytical data show beta-alanine to be an effective supplement to improve exercise outcomes, but little work exists on its efficacy during dynamic actions that are common during prolonged cycling.Beta-alanine supplementation increased muscle carnosine content but did not generate improvements in the performance of high-intensity cycling (10-s sprints or 4-km uphill time-trial) during a simulated road race cycling protocol.These data suggest that short duration sprints (≤10 s) and longer duration (>10 min) high-intensity activity throughout endurance cycling may not be improved with beta-alanine supplementation despite increases in muscle carnosine content.

Ergogenic effect of pre-exercise chicken broth ingestion on a high-intensity cycling time-trial

Background

chicken meat extract is a popular functional food in Asia. It is rich in the bioactive compounds carnosine and anserine, two histidine-containing dipeptides (HCD). Studies suggest that acute pre-exercise ingestion of chicken extracts has important applications towards exercise performance and fatigue control, but the evidence is equivocal. This study aimed to evaluate the ergogenic potential of the pre-exercise ingestion of a homemade chicken broth (CB) vs a placebo soup on a short-lasting, high-intensity cycling exercise.

Methods

fourteen men participated in this double-blind, placebo-controlled, crossover intervention study. Subjects ingested either CB, thereby receiving 46.4 mg/kg body weight of HCD, or a placebo soup (similar in taste without HCD) 40 min before an 8 min cycling time trial (TT) was performed. Venous blood samples were collected at arrival (fasted), before exercise and at 5 min recovery. Plasma HCD were measured with UPLC-MS/MS and glutathione (in red blood cells) was measured through HPLC. Capillary blood samples were collected at different timepoints before and after exercise.

Results

a significant improvement (p = 0.033; 5.2%) of the 8 min TT mean power was observed after CB supplementation compared to placebo. Post-exercise plasma carnosine (p <  0.05) and anserine (p <  0.001) was significantly increased after CB supplementation and not following placebo. No significant effect of CB supplementation was observed either on blood glutathione levels, nor on capillary blood analysis.

Conclusions

oral CB supplementation improved the 8 min TT performance albeit it did not affect the acid-base balance or oxidative status parameters. Further research should unravel the potential role and mechanisms of HCD, present in CB, in this ergogenic approach.

Aquagenic pruritus in an adolescent effectively managed with β-alanine supplementation

Aquagenic pruritus is a rare debilitating condition, which can be idiopathic, iatrogenic, or associated with systemic disease. In idiopathic cases, treatment can be challenging as options are limited and of variable efficacy. Here, we report the case of a teenage boy with refractory idiopathic aquagenic pruritus effectively managed with administration of β-alanine supplementation, a treatment gaining traction in lay media but not yet reported in the medical literature. This report adds to the limited options published for treatment of idiopathic aquagenic pruritus in pediatric patients.

Reduced Dose of Beta-Alanine Is Sufficient to Maintain Performance in Repeated Sprints

Zandona, BA, Ramos, RA, de Oliveira, CdS, McAnulty, SR, Ferreira, LHB, Smolarek, AC, Enes, AAN, Urbinati, KMdSS, Aragon, AA, Schoenfeld, BJ, and de Souza Junior, TP. Reduced Dose of Beta-Alanine Is Sufficient to Maintain Performance in Repeated Sprints. J Strength Cond Res XX(X): 000-000, 2020-Beta-alanine (BA) supplementation has been shown to be effective in improving physical performance by increasing carnosine concentration. However, it is still necessary to know the effect of a maintenance dose on performance. Thus, this study aimed to investigate the effects of a maintenance dose of BA supplementation on performance. Forty-four anaerobically trained men with 23.9 ± 3.8 years of age, 176.0 ± 0.05 cm height, 81.2 ± 7.5 kg body mass, and 15.5 ± 2.9% of body fat performed a cycle ergometer test consisting of 4 sprints of 30 s with 4 minutes of active recovery. The study comprised 3 phases: (a) presupplementation, (b) supplementation with 6.4 g·d BA or placebo, and (c) postsupplementation with a maintenance dose of 1.2 g·d of BA or interruption of supplementation. Data were analyzed using generalized estimated equations with a priori 0.05 level of significance. The placebo group and interruption group presented a lower power (7.28 ± 0.66 and 7.71 ± 0.42 W·kg vs. 8.04 ± 0.84 and 9.25 ± 1.18 W·kg, respectively; p < 0.05) during the third sprint in postsupplementation, whereas the maintenance group maintained the required power (7.47 ± 1.03 vs. 8.74 ± 1.07 W·kg; p > 0.05). The placebo group also presented higher percentage of fatigue (44.5% ± 12.3 and 44.8% ± 7.7 vs. 37.6 ± 7.2%; p = 0.021) and higher subjective perception of exertion (8.92 ± 0.90 vs. 8.00 ± 1.60; p = 0.028). Therefore, the maintenance dose of 1.2 g·d BA was effective in maintaining performance, whereas a reduction in performance was observed after supplementation interruption.

Effects of Beta-Alanine Supplementation on Physical Performance in Aerobic-Anaerobic Transition Zones: A Systematic Review and Meta-Analysis

Beta-alanine supplementation (BA) has a positive impact on physical performance. However, evidence showing a benefit of this amino acid in aerobic-anaerobic transition zones is scarce and the results controversial. The aim of this systematic review and meta-analysis is to analyze the effects of BA supplementation on physical performance in aerobic-anaerobic transition zones. At the same time, the effect of different dosages and durations of BA supplementation were identified. The search was designed in accordance with the PRISMA^® guidelines for systematic reviews and meta-analyses and performed in Web of Science (WOS), Scopus, SPORTDiscus, PubMed, and MEDLINE between 2010 and 2020. The methodological quality and risk of bias were evaluated with the Cochrane Collaboration tool. The main variables were the Time Trial Test (TTT) and Time to Exhaustion (TTE) tests, the latter separated into the Limited Time Test (LTT) and Limited Distance Test (LDT). The analysis was carried out with a pooled standardized mean difference (SMD) through Hedges' g test (95% CI). Nineteen studies were included in the systematic review and meta-analysis, revealing a small effect for time in the TTT (SMD, -0.36; 95% CI, -0.87-0.16; I² = 59%; p = 0.010), a small effect for LTT (SMD, 0.25; 95% CI, -0.01-0.51; I² = 0%; p = 0.53), and a large effect for LDT (SMD, 4.27; 95% CI, -0.25-8.79; I² = 94%; p = 0.00001). BA supplementation showed small effects on physical performance in aerobic-anaerobic transition zones. Evidence on acute supplementation is scarce (one study); therefore, exploration of acute supplementation with different dosages and formats on physical performance in aerobic-anaerobic transition zones is needed.

Dietary GABA induces endogenous synthesis of a novel imidazole peptide homocarnosine in mouse skeletal muscles

Carnosine (β-alanyl-L-histidine) is an imidazole dipeptide present at high concentrations in skeletal muscles, where it plays a beneficial role. However, oral intake of carnosine or β-alanine to increase skeletal muscle carnosine levels has disadvantages such as low efficiency and side effects. Therefore, we proposed homocarnosine (γ-aminobutyryl-L-histidine) as a novel alternative imidazole peptide for skeletal muscle based on its structural similarity to carnosine. To induce endogenous homocarnosine synthesis in skeletal muscles, mice were fed a basal diet mixed with 0, 0.5, 2, or 5% γ-aminobutyric acid (GABA) for 6 weeks. As expected, in the control group (0% GABA), GABA and homocarnosine were present in trace concentrations. Skeletal muscle homocarnosine levels were significantly increased in the 2% and 5% GABA intake groups (tenfold, P < 0.01 and 53-fold, P < 0.01; respectively) relative to those of the control group, whereas 0.5% GABA intake induced no such effect. GABA intake had no effect on the levels of carnosine, anserine, and β-alanine. Vigabatrin (inhibitor of GABA transaminase (GABA-T)) administration to mice receiving 2% GABA intake for 2 weeks led to GABA-T inhibition in the liver. Subsequently, a 43-fold increase in circulating GABA levels and a tendency increase in skeletal muscle homocarnosine levels were observed. Therefore, skeletal muscle homocarnosine synthesis can be induced by supplying its substrate GABA in tissues. As GABA availability is tightly regulated by GABA-T via GABA degradation, inhibitors of GABA or β-alanine degradation could be novel potential interventions for increasing skeletal muscle imidazole dipeptides.

Nutraceutical support in heart failure: a position paper of the International Lipid Expert Panel (ILEP)

Heart failure (HF) is a complex clinical syndrome that represents a major cause of morbidity and mortality in Western countries. Several nutraceuticals have shown interesting clinical results in HF prevention as well as in the treatment of the early stages of the disease, alone or in combination with pharmacological therapy. The aim of the present expert opinion position paper is to summarise the available clinical evidence on the role of phytochemicals in HF prevention and/or treatment that might be considered in those patients not treated optimally as well as in those with low therapy adherence. The level of evidence and the strength of recommendation of particular HF treatment options were weighed up and graded according to predefined scales. A systematic search strategy was developed to identify trials in PubMed (January 1970 to June 2019). The terms 'nutraceuticals', 'dietary supplements', 'herbal drug' and 'heart failure' or 'left verntricular dysfunction' were used in the literature search. The experts discussed and agreed on the recommendation levels. Available clinical trials reported that the intake of some nutraceuticals (hawthorn, coenzyme Q10, l-carnitine, d-ribose, carnosine, vitamin D, probiotics, n-3 PUFA and beet nitrates) might be associated with improvements in self-perceived quality of life and/or functional parameters such as left ventricular ejection fraction, stroke volume and cardiac output in HF patients, with minimal or no side effects. Those benefits tended to be greater in earlier HF stages. Available clinical evidence supports the usefulness of supplementation with some nutraceuticals to improve HF management in addition to evidence-based pharmacological therapy.

Fragmented Dosing of β-alanine Induces A Body Weight-Independent Pharmacokinetic Response

Personalised dosing of performance-enhancing food supplements is a hot topic. β-alanine is currently dosed using a fixed dose; however, evidence suggests that this might favour light compared to heavy subjects. A weight-relative dose seems to reverse this problem. In the present study, a novel dosing strategy was tested. A fragmented dose, composed of a fixed fragment of 800 mg and a weight-relative fragment of 10 mg/kg body weight, was compared to a fixed dose of 1600 mg and a weight-relative dose of 20 mg/kg body weight in a cohort of 20 subjects with a body weight ranging 48–139 kg (79.9 ± 24.4 kg). The results show that, following a fragmented dose, the influence of body weight on the pharmacokinetic response (iAUC) over a 210 min period was absent (r = −0.168; p = 0.478), in contrast to the fixed or weight-relative dose. The pharmacokinetic response also seemed more homogenous (CV% = 26%) following a fragmented dose compared to the fixed (33%) and the weight-relative dose (31%). The primary advantage of the easy-to-calculate fragmented dosing strategy is that it does not systematically favour or impair a certain weight group. Thorough dosage studies are lacking in the current field of sports and food supplements, therefore similar considerations can be made towards other (ergogenic) food supplements.

Can the Skeletal Muscle Carnosine Response to Beta-Alanine Supplementation Be Optimized?

Carnosine is an abundant histidine-containing dipeptide in human skeletal muscle and formed by beta-alanine and L-histidine. It performs various physiological roles during exercise and has attracted strong interest in recent years with numerous investigations focused on increasing its intramuscular content to optimize its potential ergogenic benefits. Oral beta-alanine ingestion increases muscle carnosine content although large variation in response to supplementation exists and the amount of ingested beta-alanine converted into muscle carnosine appears to be low. Understanding of carnosine and beta-alanine metabolism and the factors that influence muscle carnosine synthesis with supplementation may provide insight into how beta-alanine supplementation may be optimized. Herein we discuss modifiable factors that may further enhance the increase of muscle carnosine in response to beta-alanine supplementation including, (i) dose; (ii) duration; (iii) beta-alanine formulation; (iv) dietary influences; (v) exercise; and (vi) co-supplementation with other substances. The aim of this narrative review is to outline the processes involved in muscle carnosine metabolism, discuss theoretical and mechanistic modifiable factors which may optimize the muscle carnosine response to beta-alanine supplementation and to make recommendations to guide future research.

A Systematic Risk Assessment and Meta-Analysis on the Use of Oral β-Alanine Supplementation

β-Alanine supplementation is one of the world's most commonly used sports supplements, and its use as a nutritional strategy in other populations is ever-increasing, due to evidence of pleiotropic ergogenic and therapeutic benefits. Despite its widespread use, there is only limited understanding of potential adverse effects. To address this, a systematic risk assessment and meta-analysis was undertaken. Four databases were searched using keywords and Medical Subject Headings. All human and animal studies that investigated an isolated, oral, β-alanine supplementation strategy were included. Data were extracted according to 5 main outcomes, including 1) side effects reported during longitudinal trials, 2) side effects reported during acute trials, 3) effect of supplementation on circulating health-related biomarkers, 4) effect of supplementation on skeletal muscle taurine and histidine concentration, and 5) outcomes from animal trials. Quality of evidence for outcomes was ascertained using the Grading of Recommendations Assessment Development and Evaluation (GRADE) framework, and all quantitative data were meta-analyzed using multilevel models grounded in Bayesian principles. In total, 101 human and 50 animal studies were included. Paraesthesia was the only reported side effect and had an estimated OR of 8.9 [95% credible interval (CrI): 2.2, 32.6] with supplementation relative to placebo. Participants in active treatment groups experienced similar dropout rates to those receiving the placebo treatment. β-Alanine supplementation caused a small increase in circulating alanine aminotransferase concentration (effect size, ES: 0.274, CrI: 0.04, 0.527), although mean data remained well within clinical reference ranges. Meta-analysis of human data showed no main effect of β-alanine supplementation on skeletal muscle taurine (ES: 0.156; 95% CrI: -0.38, 0.72) or histidine (ES: -0.15; 95% CrI: -0.64, 0.33) concentration. A main effect of β-alanine supplementation on taurine concentration was reported for murine models, but only when the daily dose was ≥3% β-alanine in drinking water. The results of this review indicate that β-alanine supplementation within the doses used in the available research designs, does not adversely affect those consuming it.

Sports Foods and Dietary Supplements for Optimal Function and Performance Enhancement in Track-and-Field Athletes

Athletes are exposed to numerous nutritional products, attractively marketed with claims of optimizing health, function, and performance. However, there is limited evidence to support many of these claims, and the efficacy and safety of many products is questionable. The variety of nutritional aids considered for use by track-and-field athletes includes sports foods, performance supplements, and therapeutic nutritional aids. Support for sports foods and five evidence-based performance supplements (caffeine, creatine, nitrate/beetroot juice, β-alanine, and bicarbonate) varies according to the event, the specific scenario of use, and the individual athlete's goals and responsiveness. Specific challenges include developing protocols to manage repeated use of performance supplements in multievent or heat-final competitions or the interaction between several products which are used concurrently. Potential disadvantages of supplement use include expense, false expectancy, and the risk of ingesting banned substances sometimes present as contaminants. However, a pragmatic approach to the decision-making process for supplement use is recommended. The authors conclude that it is pertinent for sports foods and nutritional supplements to be considered only where a strong evidence base supports their use as safe, legal, and effective and that such supplements are trialed thoroughly by the individual before committing to use in a competition setting.

The effect of two β-alanine dosing strategies on 30-minute rowing performance: a randomized, controlled trial

Background

β-alanine (βA) supplementation has been shown to increase intramuscular carnosine content and subsequent high-intensity performance in events lasting < 4 minutes (min), which may be dependent on total, as opposed to daily, dose. The ergogenic effect of βA has also been demonstrated for 2000-m rowing performance prompting interest in whether βA may be beneficial for sustained aerobic exercise. This study therefore investigated the effect of two βA dosing strategies on 30-min rowing and subsequent sprint performance.

Methods

Following University Ethics approval, twenty-seven healthy, male rowers (age: 24 ± 2 years; body-height: 1.81 ± 0.02 m; body-mass: 82.3 ± 2.5 kg; body-fat: 14.2 ± 1.0%) were randomised in a double-blind manner to 4 weeks of: i) βA (2.4 g·d^− 1, βA1); ii) matched total βA (4.8 g on alternate days, βA2); or iii) cornflour placebo (2.4 g·d^− 1, PL). Participants completed a laboratory 30-min rowing time-trial, followed by 3x30-seconds (s) maximal sprint efforts at days 0, 14 and 28 (T1-T3). Total distance (m), average power (W), relative average power (W·kg^− 1), cardio-respiratory measures and perceived exertion were assessed for each 10-min split. Blood lactate ([La-]_b mmol·L^− 1) was monitored pre-post time-trial and following maximal sprint efforts. A 3-way repeated measures ANOVA was employed for main analyses, with Bonferonni post-hoc assessment (P ≤ 0.05).

Results

Total 30-min time-trial distance significantly increased from T1-T3 within βA1 only (7397 ± 195 m to 7580 ± 171 m, P = 0.002, ƞp² = 0.196), including absolute average power (194.8 ± 18.3 W to 204.2 ± 15.5 W, P = 0.04, ƞp² = 0.115) and relative average power output (2.28 ± 0.15 W·kg^− 1 to 2.41 ± 0.12 W·kg^− 1, P = 0.031, ƞp² = 0.122). These findings were potentially explained by within-group significance for the same variables for the first 10 min split (P ≤ 0.01), and for distance covered (P = 0.01) in the second 10-min split. However, no condition x time interactions were observed. No significant effects were found for sprint variables (P > 0.05) with comparable values at T3 for mean distance (βA1: 163.9 ± 3.8 m; βA2: 161.2 ± 3.5 m; PL: 162.7 ± 3.6 m), average power (βA1: 352.7 ± 14.5 W; βA2: 342.2 ± 13.5 W; PL: 348.2 ± 13.9 W) and lactate (βA1: 10.0 ± 0.9 mmol·L^− 1; βA2: 9.2 ± 1.1 mmol·L^− 1; PL: 8.7 ± 0.9 mmol·L^− 1).

Conclusions

Whilst daily βA may confer individual benefits, these results demonstrate limited impact of βA (irrespective of dosing strategy) on 30-min rowing or subsequent sprint performance. Further investigation of βA dosage > 2.4 g·d^− 1 and/or chronic intervention periods (> 4–8 weeks) may be warranted based on within-group observations.

24-Week β-alanine ingestion does not affect muscle taurine or clinical blood parameters in healthy males

PURPOSE

To investigate the effects of chronic beta-alanine (BA) supplementation on muscle taurine content, blood clinical markers and sensory side-effects.

METHODS

Twenty-five healthy male participants (age 27 ± 4 years, height 1.75 ± 0.09 m, body mass 78.9 ± 11.7 kg) were supplemented with 6.4 g day^-1 of sustained-release BA (N = 16; CarnoSyn™, NAI, USA) or placebo (PL; N = 9; maltodextrin) for 24 weeks. Resting muscle biopsies of the m. vastus lateralis were taken at 0, 12 and 24 weeks and analysed for taurine content (BA, N = 12; PL, N = 6) using high-performance liquid chromatography. Resting venous blood samples were taken every 4 weeks and analysed for markers of renal, hepatic and muscle function (BA, N = 15; PL, N = 8; aspartate transaminase; alanine aminotransferase; alkaline phosphatase; lactate dehydrogenase; albumin; globulin; creatinine; estimated glomerular filtration rate and creatine kinase).

RESULTS

There was a significant main effect of group (p = 0.04) on muscle taurine, with overall lower values in PL, although there was no main effect of time or interaction effect (both p > 0.05) and no differences between specific timepoints (week 0, BA: 33.67 ± 8.18 mmol kg^-1 dm, PL: 27.75 ± 4.86 mmol kg^-1 dm; week 12, BA: 35.93 ± 8.79 mmol kg^-1 dm, PL: 27.67 ± 4.75 mmol kg^-1 dm; week 24, BA: 35.42 ± 6.16 mmol kg^-1 dm, PL: 31.99 ± 5.60 mmol kg^-1 dm). There was no effect of treatment, time or any interaction effects on any blood marker (all p > 0.05) and no self-reported side-effects in these participants throughout the study.

CONCLUSIONS

The current study showed that 24 weeks of BA supplementation at 6.4 g day^-1 did not significantly affect muscle taurine content, clinical markers of renal, hepatic and muscle function, nor did it result in chronic sensory side-effects, in healthy individuals. Since athletes are likely to engage in chronic supplementation, these data provide important evidence to suggest that supplementation with BA at these doses for up to 24 weeks is safe for healthy individuals.

Ergogenic Effects of β-Alanine Supplementation on Different Sports Modalities: Strong Evidence or Only Incipient Findings?

Brisola, GMP and Zagatto, AM. Ergogenic effects of β-alanine supplementation on different sports modalities: strong evidence or only incipient findings? J Strength Cond Res 33(1): 253-282, 2019-β-Alanine supplementation is a popular nutritional ergogenic aid among the sports community. Due to its efficacy, already proven in the literature, to increase the intramuscular carnosine content (β-alanyl-L-histidine), whose main function is intramuscular buffering, β-alanine supplementation has become a nutritional strategy to improve performance, mainly in high-intensity efforts. However, although many studies present evidence of the efficacy of β-alanine supplementation in high-intensity efforts, discrepancies in outcomes are still present and the performance enhancing effects seem to be related to the specificities of each sport discipline, making it difficult for athletes/coaches to interpret the efficacy of β-alanine supplementation. Thus, this study carried out a review of the literature on this topic and summarized, analyzed, and critically discussed the findings with the objective of clarifying the current evidence found in the literature on different types of efforts and sport modalities. The present review revealed that inconsistencies are still found in aerobic parameters determined in incremental tests, except for physical working capacity at the neuromuscular fatigue threshold. Inconsistencies are also found for strength exercises and intermittent high-intensity efforts, whereas in supramaximal continuous mode intermittent exercise, the beneficial evidence is strong. In sports modalities, the evidence should be analyzed separately for each sporting modality. Thus, sports modalities that have strong evidence of the ergogenic effects of β-alanine supplementation are: cycling race of 4 km, rowing race of 2,000 m, swimming race of 100 and 200 m, combat modalities, and water polo. Finally, there is some evidence of slight additional effects on physical performance from cosupplementation with sodium bicarbonate.

Pharmacokinetics of β-Alanine Using Different Dosing Strategies

Introduction: The ergogenic response following long-term ingestion of β-alanine shows a high inter-individual variation. It is hypothesized that this variation is partially caused by a variable pharmacokinetic response induced by inferior dosing strategies. At this point most supplements are either taken in a fixed amount (× g), as is the case with β-alanine, or relative to body weight (× g per kg BW), but there is currently neither consensus nor a scientific rationale on why these or other dosing strategies should be used. The aim of this study is to objectify and understand the variation in plasma pharmacokinetics of a single oral β-alanine dose supplemented as either a fixed or a weight-relative dose (WRD) in an anthropometric diverse sample.

Methods: An anthropometric diverse sample ingested a fixed dose (1,400 mg) (n = 28) and a WRD of β-alanine (10 mg/kg BW) (n = 34) on separate occasions. Blood samples were taken before and at nine time points (up to 4 h) after β-alanine ingestion in order to establish a pharmacokinetic profile. Incremental area under the curve (iAUC) was calculated by the trapezoidal rule. Plasma β-alanine was quantified using HPLC-fluorescence.

Results: The variation coefficient (CV%) of the iAUC was 35.0% following ingestion of 1,400 mg β-alanine. Body weight explained 30.1% of the variance and was negatively correlated to iAUC (r = −0.549; p = 0.003). Interestingly, the CV% did not decrease with WRD (33.2%) and body weight was positively correlated to iAUC in response to the WRD (r = 0.488; p = 0.003).

Conclusion: Both dosing strategies evoked an equally high inter-individual variability in pharmacokinetic plasma profile. Strikingly, while body weight explained a relevant part of the variation observed following a fixed dose, correction for body weight did not improve the homogeneity in β-alanine plasma response. We suggest to put more effort into the optimization of easy applicable and scientifically justified personalized dosing strategies.

Comparison of sustained-release and rapid-release β-alanine formulations on changes in skeletal muscle carnosine and histidine content and isometric performance following a muscle-damaging protocol

β-alanine supplementation increases muscle carnosine content and improves anaerobic exercise performance by enhancing intracellular buffering capacity. β-alanine ingestion in its traditional rapid-release formulation (RR) is associated with the symptoms of paresthesia. A sustained-release formulation (SR) of β-alanine has been shown to circumvent paresthesia and extend the period of supply to muscle for carnosine synthesis. The purpose of this investigation was to compare 28 days of SR and RR formulations of β-alanine (6 g day^-1) on changes in carnosine content of the vastus lateralis and muscle fatigue. Thirty-nine recreationally active men and women were assigned to one of the three groups: SR, RR, or placebo (PLA). Participants supplementing with SR and RR formulations increased muscle carnosine content by 50.1% (3.87 mmol kg^-1ww) and 37.9% (2.62 mmol kg^-1ww), respectively. The change in muscle carnosine content in participants consuming SR was significantly different (p = 0.010) from those consuming PLA, but no significant difference was noted between RR and PLA (p = 0.077). Although participants ingesting SR experienced a 16.4% greater increase in muscle carnosine than RR, fatigue during maximal voluntary isometric contractions was significantly attenuated in both SR and RR compared to PLA (p = 0.002 and 0.024, respectively). Symptoms of paresthesia were significantly more frequent in RR compared to SR, the latter of which did not differ from PLA. Results of this study demonstrated that only participants consuming the SR formulation experienced a significant increase in muscle carnosine. Differences in the muscle carnosine response between these formulations may have practical significance for athletic populations in which small changes may have important implications on performance.

β-Alanine supplementation increased physical performance and improved executive function following endurance exercise in middle aged individuals

Background

Sarcopenia, a reduction in muscle mass and function seen in aging populations, may be countered by improving systemic carnosine stores via beta-Alanine (β-alanine) supplementation. Increasing systemic carnosine levels may result in enhanced anti-oxidant, neuro-protective and pH buffering capabilities. This enhancement should result in improved exercise capacity and executive function.

Methods

Twelve healthy adults (average age = 60.5 ± 8.6 yrs, weight = 81.5 ± 12.6 kg) were randomized and given either 2.4 g/d of β-alanine (BA) or Placebo (PL) for 28 days. Exercise capacity was tested via bouts on a cycle ergometer at 70% VO₂ peak. Executive function was measured by Stroop Tests 5 min before exercise (T1), immediately before exercise (T2), immediately following fatigue (T3), and 5 min after fatigue (T4). Lactate measures were taken pre/post exercise. Heart rate, Rating of Perceived Exertion (RPE) and VO₂ were recorded throughout exercise testing.

Results

PRE average time-to-exhaustion (TTE) for the PL and BA group were not significantly different (Mean ± SD; 9.4 ± 1.4mins vs 11.1 ± 2.4mins, respectively, P = 0.7). POST BA supplemented subjects cycled significantly longer than PRE (14.6 ± 3.8mins vs 11.1 ± 2.4mins, respectively, P = 0.04) while those given PL did not (8.7 ± 2.4mins vs 9.4 ± 1.4mins, respectively, P = 0.7). PL subjects were slower in completing the Stroop test POST at T4 compared to T3 (T3 = − 13.3 ± 8.6% vs T4 = 2.1 ± 8.3%, P = 0.04), while the BA group (T3 = − 9.2 ± 6.4% vs T4 = − 2.5 ± 3.5%, P = 0.5) was not. POST lactate production expressed a trend when comparing treatments, as the BA group produced 2.4 ± 2.6 mmol/L more lactate than the PL group (P = 0.06). Within group lactate production for BA (P = 0.4) and PL (P = 0.5), RPE (P = 0.9) and heart rate (P = 0.7) did not differ with supplementation.

Conclusion

BA supplementation increased exercise capacity and eliminated endurance exercise induced declines in executive function seen after recovery. Increased POST TTE coupled with similar PRE vs POST lactate production indicates an improvement in the ability of BA to extend exercise durations. Furthermore, by countering endurance exercise’s accompanying deficits in executive function, the aging population can maintain benefits from exercise with improved safety.

Changing to a vegetarian diet reduces the body creatine pool in omnivorous women, but appears not to affect carnitine and carnosine homeostasis: a randomised trial

Balanced vegetarian diets are popular, although they are nearly absent in creatine and carnosine and contain considerably less carnitine than non-vegetarian diets. Few longitudinal intervention studies investigating the effect of a vegetarian diet on the availability of these compounds currently exist. We aimed to investigate the effect of transiently switching omnivores onto a vegetarian diet for 6 months on muscle and plasma creatine, carnitine and carnosine homeostasis. In a 6-month intervention, forty omnivorous women were ascribed to three groups: continued omnivorous diet (control,n10), vegetarian diet without supplementation (Veg+Pla,n15) and vegetarian diet combined with dailyβ-alanine (0·8–0·4 g/d) and creatine supplementation (1 g creatine monohydrate/d) (Veg+Suppl,n15). Before (0 months; 0M), after 3 months (3M) and 6 months (6M), a fasted venous blood sample and 24-h urine was collected, and muscle carnosine content was determined by proton magnetic resonance spectroscopy (1H-MRS). Muscle biopsies were obtained at 0M and 3M. Plasma creatine and muscle total creatine content declined from 0M to 3M in Veg+Pla (P=0·013 andP=0·009, respectively), whereas plasma creatine increased from 0M in Veg+Suppl (P=0·004). None of the carnitine-related compounds in plasma or muscle showed a significant time×group interaction effect.1H-MRS-determined muscle carnosine content was unchanged over 6M in control and Veg+Pla, but increased in Veg+Suppl in soleus (P<0·001) and gastrocnemius (P=0·001) muscle. To conclude, the body creatine pool declined over a 3-month vegetarian diet in omnivorous women, which was ameliorated when accompanied by low-dose dietary creatine supplementation. Carnitine and carnosine homeostasis was unaffected by a 3- or 6-month vegetarian diet, respectively.

Effects of β-Alanine Supplementation on Carnosine Elevation and Physiological Performance

β-Alanine is one of the more popular sport supplements used by strength/power athletes today. The popularity of β-alanine stems from its ability to enhance intracellular muscle-buffering capacity thereby delaying fatigue during high-intensity exercise by increasing muscle carnosine content. Recent evidence also suggests that elevated carnosine levels may enhance cognitive performance and increase resiliency to stress. These benefits are thought to result from carnosine's potential role as an antioxidant. This review will discuss these new findings including recent investigations examining β-alanine supplementation and increased resiliency to posttraumatic stress and mild traumatic brain injury. This review will focus on the physiology of carnosine, the effect of β-alanine ingestion on carnosine elevations, and the potential ergogenic benefits it has for competitive and tactical athletes.

A urinary metabolomics (GC-MS) strategy to evaluate the antidepressant-like effect of chlorogenic acid in adrenocorticotropic hormone-treated rats

Major depressive disorder (MDD) is a chronic recurring illness that seriously affects human health. Chlorogenic acid (CGA), an important polyphenol extracted from Eucommia ulmoides Oliver bark, has been reported to have anti-depression, neuroprotection, memory improvement and other pharmacological effects. However, little is known about the underlying mechanisms of CGA on the treatment of depression. Here, we investigated the antidepressant-like effects of CGA on an adrenocorticotropic hormone (ACTH)-treated rat model. Thirty-two male Wistar rats were randomly divided into four groups: normal diet group (N), ACTH-treated model group (M), memantine positive control group (M + Mem) and CGA intervened group (M + CGA). Sucrose preference tests (SPTs) and open-field tests (OFTs) were performed to evaluate depressive-like behaviors. Memantine (30 mg kg⁻¹) and CGA (500 mg kg⁻¹) administration dramatically increased hedonic behaviors of the rats in SPT. The scores of crossing and rearing were significantly increased in the M + Mem group and M + CGA group. These results of the behaviour tests might be suggestive of antidepressant-like effects. Moreover, memantine and CGA reversed the levels of serum 5-hydroxytryptamine (5-HT), ACTH, corticotropin-releasing hormone (CRH), and dopamine (DA) that were altered in ACTH-treated rats. Based on a GC-MS metabolomic approach, significant differences in the metabolic profile were observed in ACTH-treated rats compared with the control group, as well as the M + CGA group and M + Mem group compared with the ACTH-treated group. A total of 19 metabolites were identified for the discrimination of normal rats and ACTH-treated rats, and 12 out of 19 differential metabolites were reversed with CGA intervention. Combined with pattern recognition and bioinformatics, nine perturbed metabolic pathways, including energy metabolism, neurotransmitter metabolism, and amino acid metabolism, were identified based on these metabolites. These integrative studies might give a holistic insight into the pathophysiological mechanism of the ACTH-treated depressive rat model, and also showed that CGA has antidepressant-like activities in ACTH-treated rats, providing an important drug candidate for the prevention and treatment of tricyclic anti-depressant treatment-resistant depression.

Chlorogenic acid showed antidepressant-like activity in chronic ACTH-treated rats, providing a potential drug candidate for prevention and treatment of tricyclic antidepressant treatment-resistant depression. Related metabolic pathways were shown.

No Effect of β-alanine on Muscle Function and Kayak Performance

PURPOSE

If β-alanine supplementation counteracts muscular fatigue development or improves athletic performance was investigated.

METHODS

Elite kayak rowers (10 men and 7 women) were supplemented with either 80 mg·kg body mass·d of β-alanine or placebo for 8 wk. Muscular fatigue development was investigated by applying a 2-min elbow flexor maximal voluntary contraction (MVC). EMG was recorded continuously, and voluntary activation was determined 30, 60, 90, and 115 s into the 2-min MVC. In addition, performance was evaluated as 1000-m and 5 × 250-m kayak ergometer rowing.

RESULTS

Force reduction during the 2-min MVC was similar before and after supplementation with β-alanine (30.9% ± 10.3% vs 36.0% ± 14.1%) and placebo (35.5% ± 7.7% vs 35.1% ± 8.0%). No time effect was apparent in voluntary activation during the 2-min MVC. In addition, there was no detectable effect of β-alanine supplementation on 1000-m kayak ergometer performance (β-alanine: 0.26% ± 0.02% vs placebo: -0.18% ± 0.02%) or accumulated 5 × 250-m time (β-alanine: -1.0% ± 0.3% vs placebo: -1.0% ± 0.2%). In 5 × 250 m, mean power output was reduced to a similar extent from first to fifth interval before and after supplementation with β-alanine (23% ± 11% vs 22% ± 10%) and placebo (26% ± 13% vs 20% ± 5%).

CONCLUSIONS

Two-minute MVC characteristics are unaffected by β-alanine supplementation in elite kayakers, and likewise, both a 1000-m kayak ergometer time trial lasting 4-5 min and a 5 × 250-m repeated sprint ability were unaltered by supplementation.

"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.

β-alanine supplementation improves in-vivo fresh and fatigued skeletal muscle relaxation speed

Purpose

In fresh muscle, supplementation with the rate-limiting precursor of carnosine, β-alanine (BA), results in a decline in muscle half-relaxation time (HRT) potentially via alterations to calcium (Ca²⁺) handling. Accumulation of hydrogen cation (H⁺) has been shown to impact Ca²⁺ signalling during muscular contraction, carnosine has the potential to serve as a cytoplasmic regulator of Ca²⁺ and H⁺ coupling, since it binds to both ions. The present study examined the effect of BA supplementation on intrinsic in-vivo isometric knee extensor force production and muscle contractility in both fresh and fatigued human skeletal muscle assessed during voluntary and electrically evoked (nerve and superficial muscle stimulation) contractions.

Methods

Twenty-three males completed two experimental sessions, pre- and post- 28 day supplementation with 6.4 g.day⁻¹ of BA (n = 12) or placebo (PLA; n = 11). Isometric force was recorded during a series of voluntary and electrically evoked knee extensor contractions.

Results

BA supplementation had no effect on voluntary or electrically evoked isometric force production, or twitch electromechanical delay and time-to-peak tension. There was a significant decline in muscle HRT in fresh and fatigued muscle conditions during both resting (3 ± 13%; 19 ± 26%) and potentiated (1 ± 15%; 2 ± 20%) twitch contractions.

Conclusions

The mechanism for reduced HRT in fresh and fatigued skeletal muscle following BA supplementation is unclear. Due to the importance of muscle relaxation on total energy consumption, especially during short, repeated contractions, BA supplementation may prove to be beneficial in minimising contractile slowing induced by fatigue.

Trial registration

The trial is registered with Clinicaltrials.gov, ID number NCT02819505.

Effects of Four Weeks of β-Alanine Supplementation on Repeated Sprint Ability in Water Polo Players

The purpose of this study was to investigate the effect of four weeks of β-alanine supplementation on repeated sprint ability in water polo players. Twenty-two male water polo players participated in the study, divided randomly into two homogeneous groups (placebo and β-alanine groups). The study design was double-blind, parallel and placebo controlled. Before and after the supplementation period (28 days), the athletes performed two specific repeated sprint ability tests interspaced by a 30-minute swimming test. Participants received 4.8g∙day-1 of the supplement (dextrose or β-alanine) on the first 10 days and 6.4g∙day-1 on the final 18 days. There was no significant group-time interaction for any variable. The qualitative inference for substantial changes demonstrated a likely beneficial effect in the β-alanine group (β-alanine vs placebo) for mean time (6.6±0.4s vs 6.7±0.4s; 81% likely beneficial), worst time (6.9±0.5s vs 7.1±0.5s; 78% likely beneficial) and total time (39.3±2.5s vs 40.4±2.5s; 81% likely beneficial) in the first repeated sprint ability set and for worst time (7.2±0.6s vs 7.5±0.6s; 57% possible beneficial) in the second repeated sprint ability set. Further, was found substantial change for total time for both repeated sprint ability tests (80.8±5.7s vs 83.4±5.6s; 52% possible beneficial). To conclude, four weeks of β-alanine supplementation had a likely beneficial effect in the first set of repeated sprint ability tests and a possible beneficial effect for worst time in the second set performed in a specific protocol in water polo players.

Timing, Optimal Dose and Intake Duration of Dietary Supplements with Evidence-Based Use in Sports Nutrition

[Purpose]

The aim of the present narrative review was to consider the evidence on the timing, optimal dose and intake duration of the main dietary supplements in sports nutrition, i.e. β-alanine, nitrate, caffeine, creatine, sodium bicarbonate, carbohydrate and protein.

[Methods]

This review article focuses on timing, optimal dose and intake duration of main dietary supplements in sports nutrition.

[Results]

This paper reviewed the evidence to determine the optimal time, efficacy doses and intake duration for sports supplements verified by scientific evidence that report a performance enhancing effect in both situation of laboratory and training settings.

[Conclusion]

Consumption of the supplements are usually suggested into 5 specific times, such as pre-exercise (nitrate, caffeine, sodium bicarbonate, carbohydrate and protein), during exercise (carbohydrate), post-exercise (creatine, carbohydrate, protein), meal time (β-alanine, creatine, sodium bicarbonate, nitrate, carbohydrate and protein), and before sleep (protein). In addition, the recommended dosing protocol for the supplements nitrate and β-alanine are fixed amounts irrespective of body weight, while dosing protocol for sodium bicarbonate, caffeine and creatine supplements are related to corrected body weight (mg/kg bw). Also, intake duration is suggested for creatine and β-alanine, being effective in chronic daily time < 2 weeks while caffeine, sodium bicarbonate are effective in acute daily time (1-3 hours). Plus, ingestion of nitrate supplement is required in both chronic daily time < 28 days and acute daily time (2- 2.5 h) prior exercise.

Beta-alanine supplementation enhances judo-related performance in highly-trained athletes

OBJECTIVES

In official judo competitions, athletes usually engage in 5-7 matches in the same day, performing numerous high-intensity efforts interspersed by short recovery intervals. Thus, glycolytic demand in judo is high and acidosis may limit performance. Carnosine is a relevant intracellular acid buffer whose content is increased with beta-alanine supplementation. Thus, we hypothesized that beta-alanine supplementation could attenuate acidosis and improve judo performance.

DESIGN

Twenty-three highly-trained judo athletes were randomly assigned to receive either beta-alanine (6.4gday^-1) or placebo (dextrose, same dosage) for 4 weeks.

METHODS

Performance was assessed before (PRE) and after (POST) supplementation through a 5-min simulated fight (randori) followed by 3 bouts of the Special Judo Fitness Test (SJFT). Blood samples were collected for blood pH, bicarbonate (HCO₃^-) and lactate determination.

RESULTS

Beta-alanine supplementation improved the number of throws per set and the total number of throws (both p<0.05). Placebo did not change these variables (both p>0.05). Blood pH and HCO₃^- reduced after exercise (all p<0.001), with no between-group differences (all p>0.05). However, the lactate response to exercise increased in the beta-alanine group as compared to placebo (p<0.05).

CONCLUSIONS

In conclusion, 4 weeks of beta-alanine supplementation effectively enhance judo-related performance in highly-trained athletes.

Nutritional Strategies to Modulate Intracellular and Extracellular Buffering Capacity During High-Intensity Exercise

Intramuscular acidosis is a contributing factor to fatigue during high-intensity exercise. Many nutritional strategies aiming to increase intra- and extracellular buffering capacity have been investigated. Among these, supplementation of beta-alanine (~3–6.4 g/day for 4 weeks or longer), the rate-limiting factor to the intramuscular synthesis of carnosine (i.e. an intracellular buffer), has been shown to result in positive effects on exercise performance in which acidosis is a contributing factor to fatigue. Furthermore, sodium bicarbonate, sodium citrate and sodium/calcium lactate supplementation have been employed in an attempt to increase the extracellular buffering capacity. Although all attempts have increased blood bicarbonate concentrations, evidence indicates that sodium bicarbonate (0.3 g/kg body mass) is the most effective in improving high-intensity exercise performance. The evidence supporting the ergogenic effects of sodium citrate and lactate remain weak. These nutritional strategies are not without side effects, as gastrointestinal distress is often associated with the effective doses of sodium bicarbonate, sodium citrate and calcium lactate. Similarly, paresthesia (i.e. tingling sensation of the skin) is currently the only known side effect associated with beta-alanine supplementation, and it is caused by the acute elevation in plasma beta-alanine concentration after a single dose of beta-alanine. Finally, the co-supplementation of beta-alanine and sodium bicarbonate may result in additive ergogenic gains during high-intensity exercise, although studies are required to investigate this combination in a wide range of sports.

Prevalence, knowledge and attitudes relating to β-alanine use among professional footballers

OBJECTIVES

To investigate β-alanine supplementation use and level of knowledge amongst professional footballers.

DESIGN

Cross-sectional survey of Australian professional football players.

METHODS

Questionnaires assessing β-alanine supplementation behaviours, level of knowledge and sources of information were completed by professional rugby union (RU) (n=87), rugby league (RL) (n=180) and Australian Rules Football (ARF) (n=303) players.

RESULTS

Approximately 61% of athletes reported β-alanine use, however use by ARF football players (44%) was lower than that of RU (80%) and RL players (80%). The majority of respondents were not using β-alanine in accordance with recommendations. Only 35% of the participants were able to correctly identify the potential benefits of β-alanine supplementation. The main information sources that influenced players' decision to use β-alanine were strength and conditioning coach (71%) and dietitian (52%). Forty-eight per cent of athletes never read labels prior to supplementing and only 11% completed their own research on β-alanine. Compared to RL and ARF players, RU players had both a greater knowledge of β-alanine supplementation and better supplementation practices.

CONCLUSIONS

Despite over half the surveyed professional footballers using β-alanine, the majority of athletes used β-alanine in a manner inconsistent with recommendations. A better understanding of the environment and culture within professional football codes is required before supplement use becomes consistent with evidence based supplement recommendations.