Curcumin effects on inflammation and performance recovery following eccentric exercise-induced muscle damage

Advances in relieving exercise fatigue for curcumin: Molecular targets, bioavailability, and potential mechanism

Intense and prolonged physical activity can lead to a decrease in muscle capacity, making it difficult to maintain the desired exercise intensity and resulting in exercise fatigue. The long-term effects of exercise fatigue can be very damaging to the body, so it is an urgent problem to be addressed. The intervention of foodborne active substances will be an effective measure. There is growing evidence that the molecular structure and function of curcumin have a positive effect on relieving fatigue. In this review, we summarize curcumin's molecular structure, which enables it to bind to a wealth of molecular targets, regulate signaling pathways, and thus alleviate exercise fatigue through a variety of mechanisms, including reducing oxidative stress, inhibiting inflammation, reducing metabolite accumulation, and regulating energy metabolism. The effects of curcumin on fatigue-related markers were analyzed from the perspective of animal models and human models and based on the bidirectional interaction between curcumin and intestinal microbiota: Intestinal microbiota can transform curcumin, and curcumin regulates gut microbiota through metabolic pathways, providing a new perspective for alleviating fatigue. This review contributes to a more comprehensive understanding of the possible molecular mechanisms of curcumin in anti-fatigue and provides a new possibility for the development of functional foods in the future.

Meta-analysis of the effect of curcumin supplementation on skeletal muscle damage status

OBJECTIVES

Meta-analysis was conducted to examine the effect of supplemental curcumin intake on skeletal muscle injury status and to propose an optimal intervention program.

METHODS

In accordance with the procedures specified in the PRISMA statement for systematic reviews and meta-analyses of randomized controlled trials, the Review Manager 5.3 was used to analyze the results of creatine kinase (CK), muscle soreness, interleukin-6 (IL-6), and range of motion (ROM) as outcome indicators in the 349 subjects included in the 14 articles.

RESULTS

The effect size of curcumin supplementation on muscle soreness, mean difference (MD) = -0.61; the relationship between curcumin supplementation and muscle soreness for time of measurement (I2 = 83.6%)、the relationship between curcumin supplementation and muscle soreness for period of intervention (I2 = 26.2%)、the relationship between whether one had been trained (I2 = 0%) and supplementation dose (I2 = 0%) were not heterogeneous for the relationship between curcumin supplementation and muscle soreness; The effect size on CK, MD = -137.32; the relationship between curcumin supplementation and CK (I2 = 79.7%)、intervention period (I2 = 91.9%)、whether or not trained (I2 = 90.7%)、and no heterogeneity in the relationship between curcumin supplementation and CK for the time of measurement (I2 = 0%); The effect size MD = 4.10 for the effect on ROM; The effect size for IL-6 was MD = -0.33.

CONCLUSIONS

This meta-analysis highlights that curcumin supplementation significantly mitigates skeletal muscle damage, with notable improvements in CK levels, muscle soreness, IL-6 levels, and ROM. The results highlight the importance of curcumin dosage and timing, revealing that prolonged supplementation yields the best results, especially for untrained individuals or those less exposed to muscle-damaging exercise. For muscle soreness and ROM enhancement, a pre-emptive, low-dose regimen is beneficial, while immediate post-exercise supplementation is most effective at reducing CK and IL-6 levels.

Dietary Curcumin Intake and Its Effects on the Transcriptome and Metabolome of Drosophila melanogaster

Curcumin, a polyphenol derived from Curcuma longa, used as a dietary spice, has garnered attention for its therapeutic potential, including antioxidant, anti-inflammatory, and antimicrobial properties. Despite its known benefits, the precise mechanisms underlying curcumin's effects on consumers remain unclear. To address this gap, we employed the genetic model Drosophila melanogaster and leveraged two omics tools-transcriptomics and metabolomics. Our investigation revealed alterations in 1043 genes and 73 metabolites upon supplementing curcumin into the diet. Notably, we observed genetic modulation in pathways related to antioxidants, carbohydrates, and lipids, as well as genes associated with gustatory perception and reproductive processes. Metabolites implicated in carbohydrate metabolism, amino acid biosynthesis, and biomarkers linked to the prevention of neurodegenerative diseases such as schizophrenia, Alzheimer's, and aging were also identified. The study highlighted a strong correlation between the curcumin diet, antioxidant mechanisms, and amino acid metabolism. Conversely, a lower correlation was observed between carbohydrate metabolism and cholesterol biosynthesis. This research highlights the impact of curcumin on the diet, influencing perception, fertility, and molecular wellness. Furthermore, it directs future studies toward a more focused exploration of the specific effects of curcumin consumption.

Curcumin and its nano-formulations combined with exercise: From molecular mechanisms to clinic

Curcumin is a strong substance derived from turmeric, a popular spice, renowned for its antioxidant and anti-inflammatory abilities. The study delved deeply into a thorough examination of various sources to evaluate the impact of both regular curcumin and nano-formulated curcumin on elements that impact physical performance, including muscular strain, discomfort, swelling, and oxidative tension. While engaging in exercise, the body experiences a rise in reactive oxygen species and inflammation. As a result, it is important to ensure a proper balance between internal and external sources of antioxidants to maintain stability in the skeletal muscle. Without this balance, there is a risk of muscle soreness, damage, and ultimately, a decline in exercise performance. Curcumin possesses the ability to enhance physical performance and reduce the symptoms of muscle fatigue and injury by virtue of its antioxidative and anti-inflammatory properties. Including curcumin supplements appears to have advantageous effects on various aspects of exercise, such as enhancing performance, assisting with recovery, lessening muscle damage and discomfort, and lowering levels of inflammation and oxidative stress. However, a thorough assessment is necessary to precisely gauge the healing advantages of curcumin in enhancing exercise ability and reducing recovery time.

Combined Turmeric, Vitamin C, and Vitamin D Ready-to-Drink Supplements Reduce Upper Respiratory Illness Symptoms and Gastrointestinal Discomfort in Elite Male Football Players

Elite football is associated with the increased risk of illness, although targeted supplementation can reduce illness risk. This study assessed the effects of a supplement containing turmeric root within a black pepper and fat-soluble blend, vitamin C and vitamin D, on upper respiratory symptoms (URS), gastrointestinal symptoms (GIS), muscle soreness, and markers of inflammation and gut permeability in elite male footballers. Twenty-three footballers completed 3 weeks of no intervention (CON), followed by 16 weeks of daily consuming 60 mL of a commercially available supplement containing raw turmeric root (17.5 g, estimated to contain 700 mg of curcumin), vitamin C (1000 mg), and vitamin D3 (3000 IU/75 mcg) (SUP). URS and GIS were measured daily. Immediately (0 h), 40, and 64 h after six competitive matches (two in CON, four in SUP), the subjective soreness and plasma concentrations of creatine kinase [CK], c-reactive protein [CRP], and intestinal fatty-acid binding protein [I-FABP] were assessed. URS incidence (p < 0.001), GIS (p < 0.05), and plasma [I-FABP] at 0 h (p < 0.05) were greater during CON versus SUP. At 40 h, [CRP] was greater than 0 h during CON (p < 0.01) but not SUP (p = 0.204). There were no differences in soreness or [CK]. This study indicates that turmeric root, vitamin C, and vitamin D supplementation over 16 weeks can reduce URS, GIS, and post-match [I-FABP] in elite footballers.

Effects of Turmeric Concentrate on Cardiovascular Risk Factors and Exercise-Induced Oxidative Stress in Healthy Volunteers; an Exploratory Study

Purpose

Evidence suggests that turmeric intake can improve antioxidant defense, blood pressure (BP), ageing and gut microbiota. The effects of turmeric concentrate (curcumin) intake on cardiovascular risk factors and exercise induced oxidative stress were investigated.

Methods

A randomized placebo-controlled study was performed to assess the effects of turmeric extract in healthy volunteers before and after a 30 min exercise bout. Participants (n=22) were given either turmeric concentrate or placebo supplements. Anthropometry, BP, pulse wave velocity (PWV), biomarkers of oxidative stress, perceived exertion and lipid peroxidation were assessed.

Results

In the turmeric group, the expected BP response to exercise following turmeric was blunted and the increase was not significant compared to basal values followed by a decrease in final BP and PWV values. There were no significant differences in all baseline parameters between the placebo and the curcumin groups (P>0.05). A significant increase was observed in urinary antioxidant power (P=0.031) and total polyphenol levels (P=0.022) post turmeric intervention. The distance ran by the participants taking turmeric was significantly longer (P=0.005) compared to basal value. Those who took the placebo did not show significant changes.

Conclusion

Our study suggests that turmeric concentrate intake can reduce BP and improve antioxidant, anti-inflammatory status and arterial compliance. Turmeric may improve exercise performance and ameliorates oxidative stress. Larger studies are warranted to validate these findings and test more cardiovascular risk factors.

Theracurmin Modulates Cardiac Inflammation in Experimental Model of Trypanosoma cruzi Infection

Theracurmin is a nanoparticle formulation derived from curcumin, a bioactive compound known for its antioxidant and anti-inflammatory properties. Trypanosoma cruzi, the etiological agent of Chagas disease, triggers an intense inflammatory response in mammals and also causes severe tissue damage. To evaluate the immunomodulatory and antiparasitic effects of Theracurmin, Swiss mice were experimentally infected with 10³ trypomastigote forms of the Colombian strain of T. cruzi and submitted to daily therapy with 30 mg/kg of Theracurmin. In addition, daily benznidazole therapy (100 mg/kg) was performed as a positive control. We evaluated the systemic and tissue parasitism, the survival and the body mass rate, the release of inflammatory mediators (TNF, IL-6, IL-15, CCL2 and creatine kinase) and the tissue inflammation at day 30 post-infection. Theracurmin therapy reduced the parasitemia curve without altering the animals' survival rate, and it protected mice from losing body mass. Theracurmin also reduced CCL2 in cardiac tissue, IL-15 in cardiac and skeletal tissue, and plasma CK. Even without effects on TNF and IL-6 production and tissue amastigote nests, Theracurmin reduced the leukocyte infiltrate in both evaluated tissues, even in the case of more effective results observed to the benznidazole treatment. Our data suggest Theracurmin has an immunomodulatory (CCL2, IL-15, CK and tissue leukocyte infiltration) and a trypanocidal effect (on circulating parasites) during experimental infection triggered by the Colombian strain of T. cruzi. Further investigations are necessary to comprehend the Theracurmin role performed in combination with benznidazole or other potential anti-T. cruzi chemical compounds.

Effect of curcumin supplementation on inflammatory status and muscle damage in competitive female soccer players: a placebo-controlled, singleblind, nonrandomized, crossover pilot study

PURPOSE

Curcumin, a major component of turmeric, has anti-inflammatory and antioxidative properties, which are associated with protective effects against muscle damage. This study examined the effects of dietary curcumin on inflammation and muscle damage in female competitive soccer players.

METHODS

A single-blinded, placebo-controlled, nonrandomized, crossover pilot study was conducted. Six competitive female soccer players (20.0 ± 2.0 yearsold) who participated in a 2-week preseason training program were assigned to two conditions: placebo and curcumin. The participants ingested a placebo or curcumin dosage (270 mg/day) during 2 weeks of preseason training, with 1 week of washout. Fasting blood samples were collected under resting conditions before (day 0) and after (day 15) the training period to examine changes in the concentration of interleukin 6 (IL-6), an inflammatory marker, and indices reflective of muscle damage.

RESULTS

Curcumin decreased the concentration of IL-6 released (mean decrease, -30.2 ± 28.1%), whereas no decrease was observed in the placebo condition (13.4 ± 17.4%). Changes in plasma IL-6 concentrations were significantly greater in the curcumin condition than in the placebo condition (p < 0.05). However, curcumin supplementation had no significant effects on muscle damage indices.

CONCLUSION

The present study shows that curcumin supplementation could attenuate inflammation, as indicated by IL-6 concentrations, in competitive female soccer players during the training period.

Effects of L-Carnitine Intake on Exercise-Induced Muscle Damage and Oxidative Stress: A Narrative Scoping Review

Exercise-induced muscle damage results in decreased physical performance that is accompanied by an inflammatory response in muscle tissue. The inflammation process occurs with the infiltration of phagocytes (neutrophils and macrophages) that play a key role in the repair and regeneration of muscle tissue. In this context, high intensity or long-lasting exercise results in the breakdown of cell structures. The removal of cellular debris is performed by infiltrated phagocytes, but with the release of free radicals as collateral products. L-carnitine is a key metabolite in cellular energy metabolism, but at the same time, it exerts antioxidant actions in the neuromuscular system. L-carnitine eliminates reactive oxygen and nitrogen species that, in excess, alter DNA, lipids and proteins, disturbing cell function. Supplementation using L-carnitine results in an increase in serum L-carnitine levels that correlates positively with the decrease in cell alterations induced by oxidative stress situations, such as hypoxia. The present narrative scoping review focuses on the critical evaluation of the efficacy of L-carnitine supplementation on exercise-induced muscle damage, particularly in postexercise inflammatory and oxidative damage. Although both concepts appear associated, only in two studies were evaluated together. In addition, other studies explored the effect of L-carnitine in perception of fatigue and delayed onset of muscle soreness. In view of the studies analyzed and considering the role of L-carnitine in muscle bioenergetics and its antioxidant potential, this supplement could help in postexercise recovery. However, further studies are needed to conclusively clarify the mechanisms underlying these protective effects.

Turmeric supplementation improves markers of recovery in elite male footballers: a pilot study

Football match-play causes muscle damage and provokes an inflammatory response. Rapid recovery is paramount to optimising subsequent performance and reducing injury risk. Turmeric contains high concentrations of curcumin, a polyphenol that has been shown to reduce muscle damage and soreness post-exercise in recreational exercisers. However, it is unknown whether a curcumin-containing supplement can support elite footballers recovery between matches. This applied study explored whether a turmeric supplement could improve performance, subjective and physiological markers of recovery, in elite male footballers. Twenty-four elite male footballers divided into a turmeric group, who consumed 60 mL of a turmeric drink twice per day, or a control group who did not. After 96 h of rest, baseline measurements of subjective soreness (leg and whole-body), plasma creatine kinase ([CK]), plasma C-reactive protein ([CRP]), isometric mid-thigh pull (IMTP) and counter movement jump (CMJ), were collected. Following eight competitive matches, subjective leg and whole-body soreness and plasma concentrations of inflammation markers ([CK] and [CRP]) were assessed immediately (0 h), 40 and 64 h post-match. Performance markers (IMTP and CMJ) were also assessed at 40 and 64 h post-match. Percentage change from baseline showed a main effect of group (p = 0.035, p = 0.005) and time (p = 0.002, p = 0.002) for both leg and whole-body soreness, respectively. There was a group by time interaction effect (p = 0.049) for [CRP]. There were no effects of turmeric on [CK], CMJ or IMTP. This applied study is the first in elite footballers to show that a curcumin-containing supplementation may attenuate a biomarker of inflammation [CRP] and soreness post-match play.

Curcumin (CUMINUP60®) mitigates exercise fatigue through regulating PI3K/Akt/AMPK/mTOR pathway in mice

Curcumin is a chemical constituent extracted from Curcuma longa L. Several clinical and preclinical studies have demonstrated that it can mitigate exercise fatigue, but the exact mechanism is still unknown. Therefore, we applied a mouse model of exercise fatigue to investigate the possible molecular mechanisms of curcumin's anti-fatigue effect. Depending on body mass, Kunming mice were randomly divided into control, caffeine (positive drug), and curcumin groups, and were given 28 days intragastric administration. Both the caffeine group and curcumin group showed significant improvement in exercise fatigue compared to the control group, as evidenced by the increase in time to exhaustion, as well as the higher quadriceps coefficient, muscle glycogen (MG) content, and increase in the expression of Akt, AMPK, PI3K, and mTOR proteins. While the curcumin group also significantly improved the exercise fatigue of the mice, demonstrating a lower AMP/ATP ratio and lactic acid (LA) content, and increased glycogen synthase (GS), and myonectin content compared to the caffeine group. Therefore, in the present study, we found that curcumin can exert a similar anti-fatigue effect to caffeine and may act by regulating energy metabolism through modulating the expression of the proteins in the PI3K/Akt/AMPK/mTOR pathway.

Is Curcumine Useful in the Treatment and Prevention of the Tendinopathy and Myotendinous Junction Injury? A Scoping Review

Physical activity in general and sports in particular, is a mechanism that produces stress and generates great force in the tendon and in the muscle-tendon unit, which increases the risk of injury (tendinopathies). Eccentric and repetitive contraction of the muscle precipitates persistent microtraumatism in the tendon unit. In the development of tendinopathies, the cellular process includes inflammation, apoptosis, vascular, and neuronal changes. Currently, treatments with oral supplements are frequently used. Curcumin seems to preserve, and even repair, damaged tendons. In this systematic review, we focus more especially on the benefits of curcumin. The biological actions of curcumin are diverse, but act around three systems: (a) inflammatory, (b) nuclear factor B (NF-κB) related apoptosis pathways, and (c) oxidative stress systems. A bibliographic search is conducted under the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) as a basis for reporting reliable systematic reviews to perform a Scoping review. After analysing the manuscripts, we can conclude that curcumin is a product that demonstrates a significant biological antialgic, anti-inflammatory, and antioxidant power. Therefore, supplementation has a positive effect on the inflammatory and regenerative response in tendinopathies. In addition, curcumin decreases and modulates the cell infiltration, activation, and maturation of leukocytes, as well as the production of pro-inflammatory mediators at the site of inflammation.

Impacts of turmeric and its principal bioactive curcumin on human health: Pharmaceutical, medicinal, and food applications: A comprehensive review

The yellow polyphenolic pigment known as curcumin, originating from the rhizome of the turmeric plant Curcuma longa L., has been utilized for ages in ancient medicine, as well as in cooking and food coloring. Recently, the biological activities of turmeric and curcumin have been thoroughly investigated. The studies mainly focused on their antioxidant, antitumor, anti-inflammatory, neuroprotective, hepatoprotective, and cardioprotective impacts. This review seeks to provide an in-depth, detailed discussion of curcumin usage within the food processing industries and its effect on health support and disease prevention. Curcumin's bioavailability, bio-efficacy, and bio-safety characteristics, as well as its side effects and quality standards, are also discussed. Finally, curcumin's multifaceted uses, food appeal enhancement, agro-industrial techniques counteracting its instability and low bioavailability, nanotechnology and focused drug delivery systems to increase its bioavailability, and prospective clinical use tactics are all discussed.

Nanoformulation of Curcuma longa Root Extract and Evaluation of Its Dissolution Potential

Medicinal plants have been widely used for therapeutic purposes for a long time, but they have been found to have some major issues such as low water solubility and bioavailability. In the present study, the nanoformulation of Curcuma longa L. plant extract was prepared to enhance its dissolution potential and biological activities. For the formulation of the nanosuspension, an ethanolic extract of C. longa was prepared through Soxhlet extraction using the nanoformulation technique. The nanosuspensions were formulated using four different stabilizers, namely sodium lauryl sulfate (SLS), hydroxy propyl methyl cellulose (HPMC), poly(vinyl alcohol) (PVA), and polysorbate-80 (P-80). The scanning electron microscopy (SEM), polydispersity index, and ζ potential were used for characterization of the nanoformulation. Among all of these, the surfactant stabilizer SLS was found to be the best. The average particle size of the selected optimized nanosuspension was found to be 308.2 nm with a polydispersity index (PDI) value of 0.330. The ζ potential value of the optimized nanosuspension was recorded at -33.3 mV. The SEM image indicated that the particles were slightly agglomerated, which may have occurred during lyophilization of the nanosuspension. The highest dissolution rate recorded at pH = 7 was 192.32 μg/mL, which indicates pH = 7 as the most appropriate condition for the dissolution of the C. longa nanosuspension. The antioxidant, antimicrobial, and antifungal activities of the optimized nanosuspension were also determined with regard to the coarse plant extract. The study findings suggested that the nanoprecipitation approach helps in enhancing the dissolution potential and biological activities of C. longa root extract.

12-week curcumin supplementation may relieve postexercise muscle fatigue in adolescent athletes

Introduction

High-intensity exercise causes oxidative stress, muscle soreness, and muscle fatigue, leading to reduced exercise performance. Curcumin possesses antioxidative and anti-inflammatory properties and thus alleviates postexercise damage. Therefore, this study evaluated the effect of curcumin on athletes' postexercise recovery.

Methods

A non-randomized prospective cohort investigation was done. We recruited middle and high school athletes engaged in wrestling, soccer, and soft tennis. During the 12-week daily exercise training, the participants were assigned to receive curcumin supplementation (curcumin group) or not (control group). Body composition, exercise performance, inflammatory factors, muscle fatigue, and muscle soreness were recorded at the baseline and end of the study. We used the Mann-Whitney U test to compare the participants' demographics, such as age, height, weight, and training years. The Wilcoxon test was used to compare the differences between the groups before and after curcumin supplementation.

Results

Of 28 participants (21 men and 7 women, with a mean age of 17 years), 13 were in the curcumin group and 15 in the control group. A significant decrease in muscle fatigue and muscle soreness scores was observed in the curcumin group after 12 weeks. Moreover, a significant decrease in the 8-hydroxy-2 deoxyguanosine level and a significant increase in basic metabolic rate and fat-free mass were observed in the curcumin group.

Conclusion

Curcumin can reduce muscle fatigue and soreness after exercise, indicating its potential to alleviate postexercise damage. It could be considered to cooperate with nutritional supplements in regular training in adolescent athletes.

Curcumin Attenuates Delayed-Onset Muscle Soreness and Muscle Function Deficits Following a Soccer Match in Male Professional Soccer Players

PURPOSE

To examine the effects of acute curcumin (CURC) supplementation on recovery from a soccer match in male professional players.

METHODS

In a randomized, placebo-controlled, crossover design, 11 players from the under-23 team of an English Premier League club (age 19 [1] y, body mass 79.4 [7.9] kg, height 180.8 [5.7] cm) consumed 500 mg of CURC or a control (medium-chain triglycerides) immediately and 12 and 36 hours after a 90-minute match. Countermovement jump height (CMJ), reactive strength index (RSI), delayed-onset muscle soreness (DOMS, 0-200 mm), and subjective well-being were measured before and 12, 36, and 60 hours postmatch. Global positioning systems measured external load during matches, and dietary intake was recorded across the testing period.

RESULTS

External load and dietary intake did not differ between conditions (P ≥ .246). CURC attenuated deficits in CMJ (P ≤ .004) and RSI (P ≤ .001) and reduced DOMS (P ≤ .004) at all postmatch time points (except 60 h post for RSI). The greatest difference between control and CURC was 12 hours post for CMJ (P < .001, 1.91 [4.40] cm, 95% CI, 1.25 to 2.57, g = 0.36) and RSI (P = .003, 0.40 [0.41] AU, 95% CI, 0.17 to 0.63, g = 0.90) and 36 hours post for DOMS (P < .001, 47 [23] mm, 95% CI, -67 to -27, g = 2.12).

CONCLUSIONS

CURC intake <36 hours after a soccer match attenuated DOMS and muscle function deficits, suggesting that CURC may aid recovery in professional male soccer players.

The beneficial therapeutic effects of plant-derived natural products for the treatment of sarcopenia

Sarcopenia is an age-related muscle disorder typically associated with a poor quality of life. Its definition has evolved over time, and several underlying causes of sarcopenia in the elderly have been proposed. However, the exact mechanisms involved in sarcopenia, as well as effective treatments for this condition, are not fully understood. The purpose of this article was to conduct a comprehensive review of previous evidence regarding the definition, diagnosis, risk factors, and efficacy of plant-derived natural products for sarcopenia. The methodological approach for the current narrative review was performed using PubMed, Scopus, and Web of Science databases, as well as Google Scholar (up to March 2021) in order to satisfy our objectives. The substantial beneficial effects along with the safety of some plant-derived natural products including curcumin, resveratrol, catechin, soy protein, and ginseng on sarcopenia are reported in this review. Based on clinical studies, nutraceuticals and functional foods may have beneficial effects on physical performance, including handgrip and knee-extension strength, weight-lifting capacity, time or distance travelled before feeling fatigued, mitochondrial function, muscle fatigue, mean muscle fibre area, and total number of myonuclei. In preclinical studies, supplementation with herbs and natural bioactive compounds resulted in beneficial effects including increased plantaris mass, skeletal muscle mass and strength production, increased expression of anabolic factors myogenin, Myf5 and MyoD, enhanced mitochondrial capacity, and inhibition of muscle atrophy and sarcopenia. We found that several risk factors such as nutritional status, physical inactivity, inflammation, oxidative stress, endocrine system dysfunction, insulin resistance, history of chronic disease, mental health, and genetic factors are linked or associated with sarcopenia. The substantial beneficial effects of some nutraceuticals and functional foods on sarcopenia, including curcumin, resveratrol, catechin, soy protein, and ginseng, without any significant side effects, are reported in this review. Plant-derived natural products might have a beneficial effect on various components of sarcopenia. Nevertheless, due to limited human trials, the clinical benefits of plant-derived natural products remain inconclusive. It is suggested that comprehensive longitudinal clinical studies to better understand risk factors over time, as well as identifying a treatment strategy for sarcopenia that is based on its pathophysiology, be undertaken in future investigations.

Effect of curcumin supplementation on exercise-induced muscle damage: a narrative review

Curcumin, a natural polyphenol extracted from turmeric, is a potent antioxidant and anti-inflammatory agent. In the past few decades, curcumin's ability to impact chronic inflammatory conditions such as metabolic syndrome, arthritis, and cancer has been widely researched, along with growing interest in understanding its role in exercise-induced muscle damage (EIMD). EIMD impacts individuals differently depending on the type (resistance exercise, high-intensity interval training, and running), intensity, and duration of the exercise. Exercise disrupts the muscles' ultrastructure, raises inflammatory cytokine levels, and can cause swelling in the affected limb, a reduction in range of motion (ROM), and a reduction in muscular force-producing capacity. This review focuses on the metabolism, pharmacokinetics of various brands of curcumin supplements, and the effect of curcumin supplementation on EIMD regarding muscle soreness, activity of creatine kinase (CK), and production of inflammatory markers. Curcumin supplementation in the dose range of 90-5000 mg/day can decrease the subjective perception of muscle pain intensity, increase antioxidant capacity, and reduce CK activity, which reduces muscle damage when consumed close to exercise. Consumption of curcumin also improves muscle performance and has an anti-inflammatory effect, downregulating the production of pro-inflammatory cytokines, including TNF-α, IL-6, and IL-8. Curcumin may also improve oxidative capacity without hampering training adaptations in untrained and recreationally active individuals. The optimal curcumin dose to ameliorate EIMD is challenging to assess as its effect depends on the curcumin concentration in the supplement and its bioavailability.

Nutritional Compounds to Improve Post-Exercise Recovery

The metabolic and mechanical stresses associated with muscle-fatiguing exercise result in perturbations to bodily tissues that lead to exercise-induced muscle damage (EIMD), a state of fatigue involving oxidative stress and inflammation that is accompanied by muscle weakness, pain and a reduced ability to perform subsequent training sessions or competitions. This review collates evidence from previous research on a wide range of nutritional compounds that have the potential to speed up post-exercise recovery. We show that of the numerous compounds investigated thus far, only two-tart cherry and omega-3 fatty acids-are supported by substantial research evidence. Further studies are required to clarify the potential effects of other compounds presented here, many of which have been used since ancient times to treat conditions associated with inflammation and disease.

Curcumin-Added Whey Protein Positively Modulates Skeletal Muscle Inflammation and Oxidative Damage after Exhaustive Exercise

(1) Background: Exhaustive exercise can induce muscle damage. The consumption of nutritional compounds with the ability to positively influence the oxidative balance and an exacerbated inflammatory process has been previously studied. However, little is known about the nutritional value of curcumin (CCM) when mixed with whey protein concentrate (WPC). This study was developed to evaluate the effect of CCM-added WPC on inflammatory and oxidative process control and histopathological consequences in muscle tissue submitted to an exhaustive swimming test (ET). (2) Methods: 48 animals were randomly allocated to six groups (n = 8). An ET was performed 4 weeks after the start of the diet and animals were euthanized 24 h post ET. (3) Results: WPC + CCM and CCM groups reduced IL-6 and increased IL-10 expression in muscle tissue. CCM reduced carbonyl protein after ET compared to standard AIN-93M ET and WPC + CCM ET diets. Higher nitric oxide concentrations were observed in animals that consumed WPC + CCM and CCM. Consumption of WPC + CCM or isolated CCM reduced areas of inflammatory infiltrate and fibrotic tissue in the muscle. (4) Conclusions: WPC + CCM and isolated CCM contribute to the reduction in inflammation and oxidative damage caused by the exhaustive swimming test.

Effects of Intestinal Bacterial Hydrogen Gas Production on Muscle Recovery following Intense Exercise in Adult Men: A Pilot Study

This study aimed to examine the effects of hydrogen gas (H₂) produced by intestinal microbiota on participant conditioning to prevent intense exercise-induced damage. In this double-blind, randomized, crossover study, participants ingested H₂-producing milk that induced intestinal bacterial H₂ production or a placebo on the trial day, 4 h before performing an intense exercise at 75% maximal oxygen uptake for 60 min. Blood marker levels and respiratory variables were measured before, during, and after exercise. Visual analog scale scores of general and lower limb muscle soreness evaluated were 3.8- and 2.3-fold higher, respectively, on the morning after treatment than that before treatment during the placebo trial, but not during the test beverage consumption. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentrations and production rates significantly increased with placebo consumption; no changes were observed with test beverage consumption. After exercise, relative blood lactate levels with H₂-producing milk consumption were lower than those with placebo consumption. A negative correlation was observed between the variation of 8-OHdG and the area under the curve (AUC) of breath H₂ concentrations. Lipid oxidation AUC was 1.3-fold higher significantly with H₂-producing milk than with placebo consumption. Conclusively, activating intestinal bacterial H₂ production by consuming a specific beverage may be a new strategy for promoting recovery and conditioning in athletes frequently performing intense exercises.

Curcumin: A dietary phytochemical for boosting exercise performance and recovery

Curcumin, as the main natural compound in the turmeric plant (Curcuma longa), is a yellowish polyphenol that has been used traditionally in Asian countries as a medicinal herb for various types of disease and pathological conditions caused by inflammation and oxidative stress. In the present review, we conducted a comprehensive literature search for evidence that shows the effect of curcumin on factors influencing exercise performance, including muscle damage, muscle soreness, inflammation, and oxidative stress. During exercise, reactive oxygen species and inflammation are increased. Thus, if there is no balance between endogenous and exogenous antioxidants and increases in oxidative stress and inflammation, which is important for maintaining redox homeostasis in skeletal muscle, it can lead to muscle soreness and muscle damage and ultimately result in reduced exercise performance. Due to the anti-oxidant and anti-inflammatory properties of curcumin, it can increase exercise performance and decrease exercise-induced muscle soreness and muscle damage. It appears that curcumin supplementation can have positive effects on exercise performance and recovery, muscle damage and pain, inflammation, and oxidative stress. However, there is still a need to precisely evaluate factors to more accurately assess/quantify the beneficial therapeutic effects of curcumin with regard to enhancing exercise performance and recovery.

The effect of curcumin supplementation on delayed-onset muscle soreness, inflammation, muscle strength, and joint flexibility: A systematic review and dose-response meta-analysis of randomized controlled trials

To quantify the effects of curcumin supplementation on exercise-induced muscle damage, muscle soreness, inflammatory biomarkers, muscle strength, and joint flexibility via assessment of creatine kinase (CK), visual analogue scale (VAS) score, maximal voluntary contraction (MVC), and range of motion (ROM), respectively. Online databases, including PubMed, Google Scholar, and Scopus, were searched up to February 2021. RevMan® software (version 5.3) was used for assessing the risk of bias to assess the quality of studies. The mean differences (MD) and confidence intervals (95% CI) of CK activity (IU/L), VAS score, tumor necrosis factor (TNF-α) (pg/ml), interleukin-6 (IL-6) (pg/ml), IL-8 (pg/ml), MVC (nm) and ROM (degree) were pooled using a random- or fixed-effect model. Between-study heterogeneity was assessed using χ-square or I² statistic. Ten trials met the eligibility criteria and were included in the pooled analysis. Meta-analysis showed that curcumin supplementation significantly reduced serum CK activity [WMD = -65.98 IU/L, 95% CI (-99.53 to -32.44)], muscle soreness [WMD = -0.56, 95% CI (-0.84 to -0.27)], and TNF-α concentration [WMD = -0.22 pg/ml, 95% CI (-0.33 to -0.10)]. Also, curcumin supplementation elicited significant improvements in MVC [WMD = 3.10 nm, 95% CI (1.45-4.75)] and ROM [WMD = 6.49°, 95% CI (3.91-9.07)], although no significant changes in IL-6 and IL-8 levels were found. Dose-response analysis indicated that there is a significant non-linear association between the daily dose and the final effect size regarding TNF-α. Curcumin supplementation may improve some aspects of DOMS, including muscle damage, muscle soreness, inflammation, muscle strength, and joint flexibility. Further, well-designed and high-quality studies with larger sample sizes are needed to ascertain the long-term effects and safety of curcumin supplementation.

Effects of Red-Fleshed Pitaya (Selenicereus polyrhizus) Ingestion after Strenuous Exercise on Creatine Kinase and Mitochondrial Function in Rat Muscle Cells

BACKGROUND: Free radicals formed during strenuous exercise through an increase in reactive oxygen species induce damage to tissues (e.g., muscle and liver) and cause oxidative damage to cells, resulting in mitochondrial dysfunction. AIM: As an effective method to repair mitochondrial muscle cell function, this study investigated the effects of red-fleshed pitaya (RFP) ingestion on creatine kinase (CK), which is a biomarker for muscle tissue damage, and malondialdehyde (MDA) levels during strenuous exercise. METHODS: This study involved 25 3-month-old male rats with an average weight of 200 g. The RFP extract was obtained through ethanol extraction and concentrated using an air-drying method. Rats were randomly allocated into five groups as follows: Two control groups (K1 [no-exercise, no RFP] and K2 [exercise, no RFP]) and three test groups (P1, P2, and P3; subjected to exercise and treated with 75, 150, and 300 mg kg−1 body weight of RFP, respectively). The exercise was in the form of swimming for 20 min 3 times/week for 31 days. CK and MDA were measured through an enzyme-linked immunosorbent assay, and histopathological examinations were performed through hematoxylin and eosin staining of rat muscles. RESULTS: The MDA levels after the ingestion of RFP extracts were compared between the K2 group and the P1, P2, and P3 groups. The results showed significant differences (p < 0.05 for P1 and P2, and p < 0.01 for P3), indicating the production of free radicals and CK, with features of damaged muscle cells based on histopathology. Ingestion of the RFP extract led to improvements in soleus muscle cells, resulting in cell function repair. CONCLUSION: Levels of MDA and CK increased during exercise, which caused significant muscle damage. However, after treatment with the RFP extract, the levels of both markers decreased. Thus, strenuous exercise causes an increase in reactive oxygen species, resulting in increased free radical levels. RFP ingestion decreased oxidative stress levels, thus repairing mitochondrial cell function.

Curcumin: The Golden Nutraceutical on the Road to Cancer Prevention and Therapeutics. A Clinical Perspective

Cancer is considered as the major public health scourge of the 21st century. Although remarkable strides were made for developing targeted therapeutics, these therapies suffer from lack of efficacy, high cost, and debilitating side effects. Therefore, the search for safe, highly efficacious, and affordable therapies is paramount for establishing a treatment regimen for this deadly disease. Curcumin, a known natural, bioactive, polyphenol compound from the spice turmeric (Curcuma longa), has been well documented for its wide range of pharmacological and biological activities. A plethora of literature indicates its potency as an anti-inflammatory and anti-cancer agent. Curcumin exhibits anti-neoplastic attributes via regulating a wide array of biological cascades involved in mutagenesis, proliferation, apoptosis, oncogene expression, tumorigenesis, and metastasis. Curcumin has shown a wide range of pleiotropic anti-proliferative effect in multiple cancers and is a known inhibitor of varied oncogenic elements, including nuclear factor kappa B (NF-κB), c-myc, cyclin D1, Bcl-2, VEGF, COX-2, NOS, tumor necrosis factor alpha (TNF-α), interleukins, and MMP-9. Further, curcumin targets different growth factor receptors and cell adhesion molecules involved in tumor growth and progression, making it a most promising nutraceutical for cancer therapy. To date, curcumin-based therapeutics have completed more than 50 clinical trials for cancer. Although creative experimentation is still elucidating the immense potential of curcumin, systematic validation by proper randomized clinical trials warrant its transition from lab to bedside. Therefore, this review summarizes the outcome of diverse clinical trials of curcumin in various cancer types.

Curcumin, the active substance of turmeric: its effects on health and ways to improve its bioavailability

Turmeric (Curcuma longa L.) is a spice utilized widely in India, China, and Southeast Asia as an aromatic stimulant, a food preservative, and coloring material. The commonly used names of turmeric are castor saffron, turmeric, and saffron root. Turmeric is a yellow-orange polyphenolic natural substance derived from C. longa rhizomes. It has been used to treat common inflammatory diseases, tumors, biliary diseases, anorexia, cough, topical wounds, diabetic injuries, liver disorders, rheumatism, and sinusitis. Extensive studies on the biological properties and pharmacological consequences of turmeric extracts have been conducted in recent years. Curcumin, the primary yellow biocomponent of turmeric, has anti-inflammatory, antioxidant, anticarcinogenic, antidiabetic, antibacterial, antiprotozoal, antiviral, antifibrotic, immunomodulatory, and antifungal properties. Defense assessment tests showed that curcumin is tolerated well at high doses, without adverse effects. Thus, curcumin is a highly active biological material with the potential to treat different diseases in modern medicine. This review article focuses on curcumin's biological characteristics. The most popular methods for curcumin encapsulation are also discussed. Several effective techniques and approaches have been proposed for curcuminoid capsulation, including nanocomplexing, gelation, complex coacervation, electrospraying, and solvent-free pH-driven encapsulation. This review also highlights curcumin's chemical properties, allowing the readers to expand their perspectives on its use in the development of functional products with health-promoting properties. © 2021 Society of Chemical Industry.

Effect of White Willow Bark on Delayed Onset Muscle Soreness Following Resistance Training: A Pilot Study

OBJECTIVES Delayed onset muscle soreness (DOMS) is discomfort that occurs within 8-24hrs following an unaccustomed bout of physical activity that peaks within 24-27hrs and slowly resolves on its own. White willow bark (WWB) is a nutritional supplement that is believed to have anti-inflammatory and analgesic properties like aspirin but without the risk of GI adverse effects. The purpose of this investigation is to determine the effectiveness of WWB on alleviating the symptoms of DOMS following exercise.METHODS Twenty-five individuals volunteered to participate and were randomly assigned to take WWB (798mg salicin) or placebo for 5 days following a lower body resistance training session which consisted of 5X10 lunges at 40% body weight (BW) and 3X fatigue leg press at 75%BW. Test procedures included visual analog scale (VAS), mid-thigh circumference and pressure pain threshold. VAS was measured pre, all five days of the supplementation period and day 6 (post-supplementation). All other variables were measured at pre, immediate, day 3(72hrs), and day 6 (post-supplementation).RESULTS No condition X time interaction was observed (p > 0.05) for any variable. However, VAS scores were lower in the WWB compared to the placebo for all time frames. There was a significant main effect of time for VAS scores indicating muscle soreness for hamstrings (p < 0.001), gluteal (p < 0.001), gastrocnemius (p < 0.001) and quadriceps (p < 0.001). In addition, there was a significant main effect of time for right midthigh pressure pain threshold (p = 0.02), mid-right (p < 0.001) and mid-left (p < 0.001) thigh circumference.CONCLUSIONS WWB may reduce subjective feelings of muscle soreness and appears to have analgesic properties.

Next-Generation Ultrasol Curcumin Boosts Muscle Endurance and Reduces Muscle Damage in Treadmill-Exhausted Rats

Curcumin positively affects performance during exercise and subsequent recovery. However, curcumin has limited bioavailability unless consumed in larger doses. In the current study, we examined the impact of a new formulation of curcumin, Next-Generation Ultrasol Curcumin (NGUC), which is relatively more bioavailable than natural curcumin on exhaustion time, grip strength, muscle damage parameters, and serum and muscle proteins. A total of 28 rats were randomly grouped as control (C, non-supplemented), exercise (E, non-supplemented), E+NGUC100 (supplemented with 100 mg/kg BW NGUC), and E+NGUC200 (supplemented with 200 mg/kg NGUC). Grip strength and exhaustion time were increased with NGUC supplementation (p < 0.0001). Creatine kinase (CK), lactate dehydrogenase (LDH), lactic acid (LA), myoglobin, malondialdehyde (MDA) concentrations were reduced in serum, and muscle tissue in NGUC supplemented groups (p < 0.05). In contrast, NGUC supplementation elevated the antioxidant enzyme levels compared to the non-supplemented exercise group (p < 0.01). Additionally, inflammatory cytokines were inhibited with NGUC administration (p < 0.05). NGUC decreased PGC-1α, p-4E-BP1, p-mTOR, MAFbx, and MuRF1 proteins in muscle tissue (p < 0.05). These results indicate that NGUC boosts exercise performance while reducing muscle damage by targeting antioxidant, anti-inflammatory, and muscle mass regulatory pathways.

Antifatigue effects of Hechong (Tylorrhynchus heterochaetus) through modulation of Nrf2/ARE- mediated antioxidant signaling pathway

This study was to evaluate the antifatigue effect of T. heterochaetus and explore the underlying mechanism of action. T. heterochaetus extract was treated to mice for 28 days. On the 28th day, after weight loaded swimming test. The levels of antioxidant enzymes and levels of pro- and anti-inflammatory cytokines in the liver and muscles of exercised mice were evaluated. mRNA and protein expression levels of Nrf2, SOD, HO-1, and Keap-1 were evaluated using RT-PCR and western blot analysis. The low (2.70 mg/0.5 ml/20 g) and medium (5.41 mg/0.5 ml/20 g) dose enhanced the activities of antioxidant enzymes like SOD, CAT and GPx in the liver and skeletal muscle thereby enhancing the antifatigue effect. The low and medium doses showed good anti-inflammatory effects by evaluating the levels of pro and anti-inflammatory cytokines such as TNF-α, IL-1β, IL-6, and IL-10 both in the liver and skeletal muscle. Furthermore, RT-PCR and western blot analysis showed increased expression of HO-1, SOD, Nrf2, and decreased expression of Keap-1 gene and proteins in liver and skeletal muscle of T. heterochaetus treated group mice. The current results indicate that T. heterochaetus exert the antifatigue effect through attenuating oxidative stress injury and inflammatory responses through the Nrf2/ARE-mediated signaling pathway.

Diet and redox state in maintaining skeletal muscle health and performance at high altitude

High altitude exposure leads to compromised physical performance with considerable weight loss. The major stressor at high altitude is hypobaric hypoxia which leads to disturbance in redox homeostasis. Oxidative stress is a well-known trigger for many high altitude illnesses and regulates several key signaling pathways under stressful conditions. Altered redox homeostasis is considered the prime culprit of high altitude linked skeletal muscle atrophy. Hypobaric hypoxia disturbs redox homeostasis through increased RONS production and compromised antioxidant system. Increased RONS disturbs the cellular homeostasis via multiple ways such as inflammation generation, altered protein anabolic pathways, redox remodeling of RyR1 that contributed to dysregulated calcium homeostasis, enhanced protein degradation pathways via activation calcium-regulated protein, calpain, and apoptosis. Ultimately, all the cellular signaling pathways aggregately result in skeletal muscle atrophy. Dietary supplementation of phytochemicals could become a safe and effective intervention to ameliorate skeletal muscle atrophy and enhance the physical performance of the personnel who are staying at high altitude regions. The present evidence-based review explores few dietary supplementations which regulate several signaling mechanisms and ameliorate hypobaric hypoxia induced muscle atrophy and enhances physical performance. However, a clinical research trial is required to establish proof-of-concept.

Dietary Polyphenol and Methylsulfonylmethane Supplementation Improves Immune, DAMP Signaling, and Inflammatory Responses During Recovery From All-Out Running Efforts

Nutritional ingredients with defined mechanisms of action can be useful in the recovery of the body from the physical demands of a habitual training plan. The purpose of this study was to determine the effect of dietary supplementation with optimized curcumin, pomegranate ellagitannins, and MSM (R + MSM) on immune-associated mRNA during early recovery (i.e., up to 8 h post-exercise) following all-out running efforts (5-km, 10-km, and 21.1-km). Subjects (N = 14) were randomized to either a supplement (R + MSM) or a control group using an open label design. The study was completed over a period of 31-day prior to a scheduled half-marathon race. Venous blood samples were collected into PAXgene tubes at baseline, subsequent samples were collected at 2, 4, and 8 h after each running effort. A 574-plex mRNA Immunology Array (NanoString) was measured for each sample and ROSALIND^® Advanced Analysis Software was used to examined changes in 31 annotated immune response pathways and specific mRNA changes. The greatest change in immune pathways occurred at 2 h (GSS > 3) followed by 4 h (GSS 2–3) and 8 h (GSS 1–2). R + MSM was associated with an increase in innate immunity (CAMP, LTF, TIRAP, CR1, IL1R1, CXCR1, PDCDILG2, and GNLY) and a blunted/smaller increase in damage-associated molecular pattern (DAMP) signaling/inflammation (TLR4, TLR5, S100A8, S100A9, and IFP35). We also found changes in immune-associated mRNA that have not been previously linked to exercise recovery (SOCS1, SOCS2, MME, CECAM6, MX1, IL-1R2, KLRD1, KLRK1, and LAMP3). Collectively these results demonstrate that supplementation with a combination of optimized curcumin, pomegranate ellagitannins, and methylsulfonylmethane resulted in changes that may improve biological recovery from all-out running efforts.

Current clinical developments in curcumin-based therapeutics for cancer and chronic diseases

The last decade has seen an unprecedented rise in the prevalence of chronic diseases worldwide. Different mono-targeted approaches have been devised to treat these multigenic diseases, still most of them suffer from limited success due to the off-target debilitating side effects and their inability to target multiple pathways. Hence a safe, efficacious, and multi-targeted approach is the need for the hour to circumvent these challenging chronic diseases. Curcumin, a natural compound extracted from the rhizomes of Curcuma longa, has been under intense scrutiny for its wide medicinal and biological properties. Curcumin is known to manifest antibacterial, antiinflammatory, antioxidant, antifungal, antineoplastic, antifungal, and proapoptotic effects. A plethora of literature has already established the immense promise of curcuminoids in the treatment and clinical management of various chronic diseases like cancer, cardiovascular, metabolic, neurological, inflammatory, and infectious diseases. To date, more than 230 clinical trials have opened investigations to understand the pharmacological aspects of curcumin in human systems. Still, further randomized clinical studies in different ethnic populations warrant its transition to a marketed drug. This review summarizes the results from different clinical trials of curcumin-based therapeutics in the prevention and treatment of various chronic diseases.

Effects of Four Weeks of Concurrent Taekwondo Plus Resistance Training on Post-exercise Blood Biomarkers of Physiological Stress in Previously-Trained Individuals

Background: Various training protocols have been used in combat sports, including Taekwondo (TKD), to rapidly improve performance and to avoid injury by balancing the exercise intensity and the athletes’ metabolic tolerance and hormonal response. However, little is known about such metabolic responses in previously-trained individuals. Objectives: To investigate the effects of a concurrent TKD plus resistance (RT) training program on post-exercise blood biomarkers of physiological stress in previously-trained individuals. Methods: Twenty-eight (16 males: 12 females) previously-trained individuals aged 20 - 26 years were matched by gender and randomly divided into either moderate- to vigorous-intensity exercising group (MODG) or a high-intensity exercising group (HIG). The MODG performed TKD training at a target training intensity of 55 - 70% (weeks 1 - 2) and 70 - 85% (weeks 3 - 4) maximum heart rate (HRmax) and RT training for four sets of 10 - 15 repetitions for each of the 13 whole-body RT exercises. The HIG performed TKD training at a target training intensity of 85 - 100% (weeks 1 - 2) and 95 - 100% (weeks 3 - 4) HRmax and RT training for five sets of 10 - 15 repetitions for each of the 13 whole-body RT exercises. A structured taekwondo tasks (sTT) test was conducted before and after the training period. Results: Significant post-exercise improvements were found for total testosterone (P = 0.02), free testosterone (P = 0.01), C/T ratio (P = 0.03) and lactate (P = 0.03) in the mixed gender HIG. With regards to the specific gender effects, post-exercise improvements were found in S-CPK in the male MODG and HIG, with improvements in uric acid only in the male HIG. In turn, post-exercise improvements were found for total testosterone, testosterone binding globulin, free testosterone in the female MODG and HIG, with post-exercise improvements in S-CPK and uric acid in the female HIG only. Conclusions: This study demonstrates that even a short period of concurrent taekwondo and resistance training improves adaptation and post-exercise responses to physiological stress, and such adaptation may even be more marked in previously-trained female athletes. Thus, this mode of training may provide a novel exercise training modality to rapidly improve an individuals’ capacity to exercise, especially in situations of plateau, while avoiding overtraining and an increased concomitant chance of illness and musculoskeletal injury.

Excessive Treadmill Training Produces different Cardiac-related MicroRNA Profiles in the Left and Right Ventricles in Mice

High-volume training followed by inadequate recovery may cause overtraining. This process may undermine the protective effect of regular exercise on the cardiovascular system and may increase the risk of pathological cardiac remodelling. We evaluated whether chronic overtraining changes cardiac-related microRNA profiles in the left and right ventricles. C57BL/6 mice were divided into the control, normal training, and overtrained by running without inclination, uphill running or downhill running groups. After an 8-week treadmill training protocol, the incremental load test and training volume results showed that the model had been successfully established. The qRT-PCR results showed increased cardiac miR-1, miR-133a, miR-133b, miR-206, miR-208b and miR-499 levels in the left ventricle of the downhill running group compared with the left ventricle of the control group. Similarly, compared with the control group, the downhill running induced increased expression of miR-21, miR-17–3p, and miR-29b in the left ventricle. Unlike the changes in the left ventricle, no difference in the expression of the tested miRNAs was observed in the right ventricle. Briefly, our results indicated that overtraining generally affects key miRNAs in the left ventricle (rather than the right ventricle) and that changes in individual miRNAs may cause either adaptive or maladaptive remodelling with overtraining.

The Effects of Curcumin Supplementation on Muscle Damage, Oxidative Stress, and Inflammatory Markers in Healthy Females with Moderate Physical Activity: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

BACKGROUND

Exercise-induced oxidative stress, muscle damage, and inflammation represent major contributors to why athletes use ergogenic aids. Turmeric is used as a spice because of its polyphenol ingredient named curcumin. We assessed the effects of curcumin supplementation on inflammatory, oxidative stress markers, muscle damage, and anthropometric indices in women with moderate physical activity.

METHODS

This double-blind, placebo-controlled clinical trial was conducted on 80 women with moderate physical activity levels (defined as walking or swimming for at least 1 h per day) for 8 weeks. Mean ± SD of age (years) all participants was 21 ± 2. Participants were randomly assigned into two groups: curcumin (500 mg/day) and placebo (500 mg/day cornstarch). Serum C-reactive protein (CRP), total antioxidant capacity (TAC), malondialdehyde (MDA), lactate dehydrogenase (LDH) levels, body composition, and maximum oxygen uptake (VO2 max) were evaluated before and after an intervention.

RESULTS

Sixty-five subjects completed the 8-week intervention. Within analysis indicated a significant decrease in CRP, LDH, MDA levels, and a significant increase in VO2 max in the curcumin group after an intervention (P < 0.05). There were significant decreases in CRP (P = 0.002), LDH (P = 0.041), and MDA (P = 0.005), no significant increase in TAC, and significant increase in VO2 max (P = 0.0001) levels in the curcumin group compared with placebo group. There were no significant changes in weight, body mass index, body fat, and lean body mass between two groups.

CONCLUSIONS

Our findings indicated that 8-week curcumin administration could significantly improve CRP, LDH, MDA, and VO2 max. Curcumin supplementation did not elicit significant changes in anthropometric indices in this study.

Short Term, Oral Supplementation with Optimized Curcumin Does Not Impair Performance Improvements Associated with High Intensity Interval Training

Curcumin may improve athletic performance through a reduction in inflammation following exercise and improve mental states of well-being. The purpose of this investigation was to explore the effects of a 14 day HIIT intervention and oral supplementation with Longvida^® optimized curcumin on athletic performance, lactate response, and well-being. Sixteen males and twenty females participated in a double-blinded, randomized, placebo-controlled trial to explore the effects of Longvida(R) optimized curcumin (1.0 g/day) and or a placebo (PLA) taken daily during a 14 day HIIT protocol. Participants were randomized into two groups, then evaluated in three groups, curcumin-fast (CURF), curcumin-slow (CURS) and placebo. Curcumin-fast and curcumin-slow were separated by their 16.1 km cycling time trial performance (TT) with CURF and CURS determined by a TT <30 min and >30 min at the pre intervention time point, respectively. Cycling time-trial performance, blood lactate response, and well-being assessments were determined at pre and post 14 day HIIT intervention time points. Blood lactate was recorded at baseline, 8.01 km, 15.1 km, and 1 min post, and 4 min post of the pre and post intervention TT. Following the internvetion, CONP and CURS experienced with 8.15% and 5.04% improvements in TT performance times, while CURF experienced a 0.57% improvement in TT performance time. No changes were observed with respect to other measures. When curcumin is taken daily in conjunction with 14 days of HIIT on a cycle ergometer, cycling performance in either well trained or more recreationally trained athletes is not impaired. Although the improvements in TT performance were not stasticially significant, they are noteworthy.

Curcumin Attenuates Sarcopenia in Chronic Forced Exercise Executed Aged Mice by Regulating Muscle Degradation and Protein Synthesis with Antioxidant and Anti-inflammatory Effects

The aim of the current study is to investigate the effects of spray dry powders of Curcuma longa containing 40% curcumin (CM-SD), as a new aqueous curcumin formula, on sarcopenia in chronic forced exercise executed 10 month old ICR mice. CM-SD (80 and 40 mg/kg) increased calf thicknesses and strengths, total body and calf protein amounts, and muscle weights in both gastrocnemius and soleus muscles. mRNA expressions regarding muscle growth and protein synthesis were induced, while those of muscle degradation significantly declined in CM-SD treatment. CM-SD decreased serum biochemical markers, lipid peroxidation, and reactive oxygen species and increased endogenous antioxidants and enzyme activities. It also reduced immunoreactive myofibers for apoptosis and oxidative stress markers but increased ATPase in myofibers. These results suggest that CM-SD can be an adjunct therapy to exercise-based remedy that prevents muscle disorders including sarcopenia by anti-apoptosis, anti-inflammation, and antioxidation-mediated modulation of gene expressions related to muscle degradation and protein synthesis.

Obesity-induced alterations to the immunoproteasome: a potential link to intramuscular lipotoxicity

Although the mechanisms are unclear, inflammation and/or lipotoxicity likely contribute to obese muscle pathology. The immunoproteasome is known to respond to inflammation and oxidative damage and may aid muscle regeneration. We sought to determine whether diet-induced obesity (DIO) influences the immunoproteasome subunits LMP7 and MECL-1 in mouse muscle with and without exercise-induced muscle damage (EIMD). Muscle mass, regeneration, macrophage content and lipid peroxidation (8-isoprostane) were also assessed. Sixty male, 4-week-old C57BL/6J mice were fed a high-fat (HFD) or low-fat diet for 12 weeks. Mice were then subdivided into EIMD or no muscle damage (NMD) groups. The gastrocnemius muscle was excised 1 or 5 days after EIMD, producing 6 groups (n = 10/group). Body mass was greater; however, relative gastrocnemius mass was lower in HFD-fed mice. Despite no macrophage or MECL-1 alterations, LMP7 and 8-isoprostane were increased in obese mice in the NMD and 1 day post-EIMD groups. However, 8-isoprostane was reduced in obese mice 5 days post-EIMD, and accompanied by increased muscle LMP7, MECL-1 and macrophage content. Consequently, DIO may impair the immunoproteasome's ability to control muscle lipid peroxidation but is reversed with eccentric exercise. Although muscle regeneration was unchanged, immunoproteasome dysregulation occurs in obese muscle and may contribute to muscle pathology. Novelty: DIO may impair the intramuscular immunoproteasome response to lipid peroxidation. Acute eccentric exercise may protect obese individuals from muscle lipotoxicity via immunoproteasome upregulation.

Protective effects of whey protein concentrate admixtured of curcumin on metabolic control, inflammation and oxidative stress in Wistar rats submitted to exhaustive exercise

This work aimed to evaluate the effects of whey protein concentrate (WPC) admixtured of curcumin on metabolic control, inflammation and oxidative stress in Wistar rats submitted to exhaustive exercise. A total of forty-eight male rats were divided into six experimental groups (n 8): standard diet group (AIN-93M), standard diet submitted to exhaustion test group (AIN-93M ET), WPC admixtured of curcumin group (WPC + CCM), WPC + CCM submitted to exhaustion test group (WPC + CCM ET), CCM group and CCM subjected to exhaustion test group (CCM ET). The swimming exhaustion test was performed after 4 weeks of experiment. The consumption of WPC + CCM as well as isolated CCM did not alter the biometric measurements, the animals' food consumption and the hepatic and kidney function, as well as the protein balance of the animals (P > 0·05), but reduced the glycaemia and the gene expression of TNF-α and IL-6 and increased the expression of IL-10 (P < 0·05). The animals that were submitted to the exhaustion test (AIN-93M ET) showed higher aspartate aminotransferase values when compared to the animals that did not perform the exercise (AIN-93 M) (P < 0·05). WPC + CCM reduced the concentration of nitric oxide, carbonylated protein and increased the concentration of catalase (P < 0·05). Both (WPC + CCM and CCM) were able to increase the concentrations of superoxide dismutase (P < 0·05). We concluded that the WPC admixtured of CCM represents a strategy capable of decreasing blood glucose and oxidative and inflammatory damage caused by exhaustive physical exercise in swimming.

Improved recovery from skeletal muscle damage is largely unexplained by myofibrillar protein synthesis or inflammatory and regenerative gene expression pathways

The contribution of myofibrillar protein synthesis (MyoPS) to recovery from skeletal muscle damage in humans is unknown. Recreationally active men and women consumed a daily protein-polyphenol beverage targeted at increasing amino acid availability and reducing inflammation (PPB; n = 9), both known to affect MyoPS, or an isocaloric placebo (PLA; n = 9) during 168 h of recovery from 300 maximal unilateral eccentric contractions (EE). Muscle function was assessed daily. Muscle biopsies were collected for 24, 27, 36, 72, and 168 h for MyoPS measurements using ²H₂O and expression of 224 genes using RT-qPCR and pathway analysis. PPB improved recovery of muscle function, which was impaired for 5 days after EE in PLA (interaction P < 0.05). Acute postprandial MyoPS rates were unaffected by nutritional intervention (24-27 h). EE increased overnight (27-36 h) MyoPS versus the control leg (PLA: 33 ± 19%; PPB: 79 ± 25%; leg P < 0.01), and PPB tended to increase this further (interaction P = 0.06). Daily MyoPS rates were greater with PPB between 72 and 168 h after EE, albeit after function had recovered. Inflammatory and regenerative signaling pathways were dramatically upregulated and clustered after EE but were unaffected by nutritional intervention. These results suggest that accelerated recovery from EE is not explained by elevated MyoPS or suppression of inflammation.NEW & NOTEWORTHY The present study investigated the contribution of myofibrillar protein synthesis (MyoPS) and associated gene signaling to recovery from 300 muscle-damaging, eccentric contractions. Measured with ²H₂O, MyoPS rates were elevated during recovery and observed alongside expression of inflammatory and regenerative signaling pathways. A nutritional intervention accelerated recovery; however, MyoPS and gene signaling were unchanged compared with placebo. These data indicate that MyoPS and associated signaling do not explain accelerated recovery from muscle damage.

Ten Days of Curcumin Supplementation Attenuates Subjective Soreness and Maintains Muscular Power Following Plyometric Exercise

Curcumin has become a popular product used to decrease inflammation and enhance recovery from exercise.

PURPOSE

To determine the effects of curcumin supplementation on delayed onset muscle soreness and muscle power following plyometric exercise.

METHODS

Participants (n = 22; five females, 17 males) consumed either curcumin (500 mg) or placebo twice daily for 10 days (6 days pre, day of and 3 days post exercise). Participants completed 5 x 20 drop jumps on day 7. Blood sampling and recovery tests were assessed at pre-supplementation, 24-hours and immediately pre-exercise, and immediately post-, 24, 48 and 72-hours post-exercise. Blood markers included serum creatine kinase (CK) and erythrocyte sedimentation rate (ESR), while soreness was measured during a squat and post vertical jump.

RESULTS

Both groups experienced muscle damage post-exercise with elevated CK (403 ± 390 ul; p < 0.01), soreness with squatting (38 ± 29 mm; p < 0.01), and vertical jump (36 ± 30 mm; p < 0.01). Soreness was greater in placebo vs. curcumin 48 h and 72 h post-exercise (p < 0.01); however, CK was not significantly different between groups (p = 0.28) despite being >200 IU·L^-1 greater 24 hr post exercise in placebo vs. curcumin. ESR was significantly greater immediately post-exercise (6.3 ± 5.6 vs. 3.4 ± 2.6 mm/hr; p = 0.03), however these were within the normal range for this test and not significantly different between groups (p = 0.25). Vertical jump decreased over time in the placebo, but not curcumin group (19.8 ± 4.8 vs. 21.4 ± 3.2 in; p = 0.01).

CONCLUSION

These data suggest curcumin reduces soreness and maintains muscular power following plyometric exercise.

Changes in Behaviour and Voluntary Physical Activity Exhibited by Sled Dogs throughout Incremental Exercise Conditioning and Intermittent Rest Days

Participation in repetitive endurance training decreases sled dogs' voluntary activity and locomotive behaviours; however, the changes in their voluntary physical activity over consecutive rest days has not been examined to assess exercise-recovery. The objective of this study was to examine the changes in behaviour and voluntary activity of sled dogs throughout repetitive incremental conditioning and intermittent rest days. Fourteen dogs (6 males, 8 females; age 3.7 ± 2.7 years; BW 21.5 ± 2.8 kg) underwent 10 weeks of conditioning. Once a week, 5-min video recordings were taken pre- and post-exercise to measure the time spent performing agonistic behaviours, chewing on the gangline, digging, jumping, lunging, posture changing, sitting, standing and lying. Additionally, voluntary physical activity was measured on a day with an exercise bout during baseline, week 4, 5 and 7 and two consecutive rest days during baseline, week 1, 4, 5 and 7. A repeated-measures mixed model was used to analyse data in SAS (v 9.4.). As dogs progressed through their conditioning, the time spent changing posture prior to an exercise bout decreased (p < 0.05), suggesting that dogs may reduce their voluntary locomotive behaviours with increasing exercise. Additionally, dogs were more active during the second consecutive rest day than the first (p < 0.05), suggesting that rest days may provide a short-term recovery period.

Marine Phytoplankton Improves Exercise Recovery in Humans and Activates Repair Mechanisms in Rats

This study investigated the effects of marine phytoplankton supplementation on 1) perceived recovery and ground reaction forces in humans following a non-functional overreaching resistance-training program and 2) myogenic molecular markers associated with muscle cell recovery in a rat model. In the human trial, a 5-week resistance-training program with intentional overreaching on weeks 2 and 5 was implemented. Results indicate that marine phytoplankton prompted positive changes in perceived recovery at post-testing and, while both marine phytoplankton and placebo conditions demonstrated decreased peak and mean rate of force development following the overreaching weeks, placebo remained decreased at post-testing while marine phytoplankton returned to baseline levels. In the rat model, rats were divided into four conditions: (i) control, (ii) exercise, (iii) exercise + marine phytoplankton 2.55 mg·d^-1, or (iv) exercise+marine phytoplankton 5.1 mg·d^-1. Rats in exercising conditions performed treadmill exercise 5 d·wk^-1 for 6 weeks. Marine phytoplankton in exercising rats increased positive and decrease negative myogenic factors regulating satellite cell proliferation. Taken together, marine phytoplankton improved perceptual and functional indices of exercise recovery in an overreaching human model and, mechanistically, this could be driven through cell cycle regulation and a potential to improve protein turnover.

The effect of curcumin supplementation on recovery following exercise-induced muscle damage and delayed-onset muscle soreness: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

curcumin consumption may have a protective effect against exercise-induced muscle damage (EIMD) through stabilization of the cell membrane via inhibition of free radical formation. Evidence supporting a protective role of curcumin after physical activity induced muscle injury in humans, however, it is inconsistent.

METHODS

Medline, Scopus, and Google scholar were systematically searched up to May 2020. The Cochrane Collaboration tool for assessing the risk of bias was used for assessing the quality of studies. Random effects model, weighted mean difference (WMD), and 95% confidence interval (CI) were used for estimating the overall effect. Between-study heterogeneity was assessed using the chi-squared and I² statistic.

RESULTS

The results revealed a significant effect of curcumin supplementation on reducing creatine kinase (CK) (weighted mean difference [WMD] = -48.54 IU.L^-1 ; 95% CI: -80.667, -16.420; p = .003) and muscle soreness index decrease (WMD = -0.476; 95% CI: -0.750, -0.202; p = .001). Moreover, a subgroup analysis resulted in a significant decrease in CK concentrations and muscle soreness index, according to follow-ups after exercise, dose of curcumin, duration of studies, exercise type, train status and study design.

CONCLUSIONS

The current evidence revealed a efficacy of curcumin in reducing CK serum levels and muscle soreness index among adults. Therefore, curcumin may be known as a priority EIMD recovery agent in interventions.

Effects of Curcumin and Fenugreek Soluble Fiber on the Physical Working Capacity at the Fatigue Threshold, Peak Oxygen Consumption, and Time to Exhaustion

Herrick, LP, Goh, J, Menke, W, Campbell, MS, Fleenor, BS, Abel, MG, and Bergstrom, HC. Effects of curcumin and fenugreek soluble fiber on the physical working capacity at the fatigue threshold, peak oxygen consumption, and time to exhaustion. J Strength Cond Res 34(12): 3346-3355, 2020-The purpose of this study was to examine the effects of curcumin in combination with fenugreek soluble fiber (CUR + FEN) or fenugreek soluble fiber alone (FEN) on the neuromuscular fatigue threshold (PWCFT), peak oxygen consumption (V˙o2peak), and time to exhaustion (Tlim) on a graded exercise test (GXT), in untrained subjects. The PWCFT estimates the highest power output that can be maintained without evidence of neuromuscular fatigue. Forty-seven untrained, college-aged subjects were randomly assigned to one of 3 supplementation groups; placebo (PLA, n = 15), CUR + FEN (500 mg·d, n = 18), or FEN (300 mg·d, n = 14). The subjects completed a maximal GXT on a cycle ergometer to determine the PWCFT, V˙o2peak, and Tlim before (PRE) and after (POST) 28 days of daily supplementation. Surface electromyographic signals were recorded from a bipolar electrode arrangement on the vastus lateralis of the right leg during each test. Separate one-way analysis of covariances were used to determine if there were between-group differences for adjusted POST-PWCFT, POST-V˙o2peak, and POST-Tlim values, covaried for the respective PRE-test scores. The adjusted POST-PWCFT for the CUR + FEN group (mean ± SD: 196 ± 58 W) was greater (p = 0.016) than the PLA group (168 ± 49 W) but the FEN group (185 ± 32 W) was not different from the CUR + FEN or PLA groups (p > 0.05). There were no differences for adjusted POST-V˙o2peak (p = 0.612) or POST-Tlim (p = 0.508) among the groups. These findings suggested curcumin combined with fenugreek soluble fiber might delay neuromuscular fatigue.

Curcumin supplementation and delayed onset muscle soreness (DOMS): effects, mechanisms, and practical considerations

[Purpose]

In this literature review we aimed to investigate the effects of curcumin supplementation on delayed onset muscle soreness (DOMS), which occurs after exercise, and evaluate related parameters to propose practical recommendations for the field of exercise physiology.

[Methods]

Experimental studies conducted on curcumin supplementation and DOMS were systematically reviewed to determine (1) the effect of curcumin supplementation on DOMS, (2) potential mechanisms by which curcumin supplementation may attenuate DOMS, and (3) practical considerations for curcumin supplementation.

[Results]

While several studies have reported that curcumin supplementation attenuates DOMS after exercise, others have reported that curcumin supplementation has no effect on DOMS. Several mechanisms have been proposed by which curcumin supplementation may attenuate DOMS; the most probable of which is a reduction in inflammatory response. Other potential mechanisms include modulation of transient receptor potential vanilloid 1 (TRPV1) or changes in post-exercise capillary lactate levels; these require further examination. The usual recommended dose of curcumin is 150–1500 mg daily (sometimes up to 5 g), divided into 2–3 portions and taken before and after exercise. It is not necessary to take curcumin together with piperine.

[Conclusion]

Although conflicting results regarding the effects of curcumin supplementation on DOMS exist in literature, it may be considered as a method of nutritional intervention for reducing post-exercise DOMS.

Intensive Running Enhances NF-κB Activity in the Mice Liver and the Intervention Effects of Quercetin

Background: Emerging evidence has supported that intensive exercise induces weakened performance and immune and metabolic disorders. We systematically evaluated the effects of quercetin against hepatic inflammatory damage caused by repeated intensive exercise and explored the potential mechanism. Methods: Male BALB/c mice were administered quercetin (100 mg/kg BW) for four weeks, and performed a treadmill running protocol of 28 m/min, 5° slope, 90 min/day concurrently for the last seven days. Results: Quercetin administration reduced the leakage of aspartic acid and alanine aminotransferase and improved ultrastructural abnormalities such as swelling, and degeneration caused by high-intensity running in mice. Quercetin significantly decreased the hepatic and plasmatic levels of inflammatory cytokines IL-1β, IL-6, TNF-α, inducible nitric oxide synthase, cyclooxygenase-2 and intercellular adhesion molecule-1—provoked by over-exercise. Furthermore, diminished activation and nuclear translocation of NF-κB were found after quercetin treatment through inhibiting IKKα and Iκbα phosphorylation of intensive running mice. Conclusion: Quercetin offers protection for mouse livers against intensive sports-induced inflammatory injury, and the suppression of the NF-κB signal transduction pathway may play a role in its anti-inflammatory effects. Our findings broaden our understanding of natural phytochemicals as a promising strategy to prevent excessive exercise damage.