Quercetin's influence on exercise-induced changes in plasma cytokines and muscle and leukocyte cytokine mRNA

Effect of onion (Allium cepa L.) peel extract on natural killer cell and cytokines in a randomized, double-blind, placebo-controlled trial

BACKGROUND/OBJECTIVES

Onion, particularly onion peel, is a quercetin-rich food with, anti-inflammatory and immunomodulatory effects. However, the effect of onion peel extract (OPE) in humans is unclear. Thus, the present study aimed to investigate whether OPE improves natural killer (NK) cell activity and cytokine concentration in a randomized double-blind placebo-controlled trial.

SUBJECTS/METHODS

Eighty participants aged 19-64 yrs old with a white blood cell count of 4,000-10,000 cells/µL, symptoms of upper respiratory infection at least once within the previous 12 mon, and perceived stress scale (PSS) over 14 were included. Participants were randomly assigned to take either 1,000 mg/day OPE or a placebo for 8 weeks.

RESULTS

Compliance were 87.4 ± 8.6% and 86.9 ± 79.0% in OPE and placebo groups. Compared to the placebo, OPE supplementation improved "Hoarseness" (P = 0.038) of the Wisconsin Upper Respiratory Symptom Survey (WURSS)-21 symptom, and stress scores (P = 0.001; 0.021) of PSS. Supplementation of OPE had no significant effect on NK cell activity and concentrations of cytokines such as interleukin (IL)-2, IL-6, IL-12, IL-1β, interferon-γ, and tumor necrosis factor-α. At baseline, the WURSS-21 symptom and PSS score (P = 0.024; 0.026) were higher in the OPE group than the placebo group. Among participants with higher than median WURSS-21 symptom score, OPE supplementation increased NK cell activity (P = 0.038). Supplementation of OPE had no significant effects on safety measurements and adverse events.

CONCLUSIONS

The present study suggested that OPE supplementation improves NK cell activity in participants with moderate upper respiratory symptoms without any significant adverse effects.

Trial Registration

ClinicalTrials.gov Identifier: NCT05666752.

The Use of Some Polyphenols in the Modulation of Muscle Damage and Inflammation Induced by Physical Exercise: A Review

Food bioactive compounds (FBC) comprise a vast class of substances, including polyphenols, with different chemical structures, and they exert physiological effects on individuals who consume them, such as antioxidant and anti-inflammatory action. The primary food sources of the compounds are fruits, vegetables, wines, teas, seasonings, and spices, and there are still no daily recommendations for their intake. Depending on the intensity and volume, physical exercise can stimulate oxidative stress and muscle inflammation to generate muscle recovery. However, little is known about the role that polyphenols may have in the process of injury, inflammation, and muscle regeneration. This review aimed to relate the effects of supplementation with mentation with some polyphenols in oxidative stress and post-exercise inflammatory markers. The consulted papers suggest that supplementation with 74 to 900 mg of cocoa, 250 to 1000 mg of green tea extract for around 4 weeks, and 90 mg for up to 5 days of curcumin can attenuate cell damage and inflammation of stress markers of oxidative stress during and after exercise. However, regarding anthocyanins, quercetins, and resveratrol, the results are conflicting. Based on these findings, the new reflection that was made is the possible impact of supplementation associating several FBCs simultaneously. Finally, the benefits discussed here do not consider the existing divergences in the literature. Some contradictions are inherent in the few studies carried out so far. Methodological limitations, such as supplementation time, doses used, forms of supplementation, different exercise protocols, and collection times, create barriers to knowledge consolidation and must be overcome.

Exertional heat stroke: nutritional considerations

NEW FINDINGS

What is the topic of this review? The potential role of nutrition in exertional heat stroke. What advances does it highlight? Certain nutritional and dietary strategies used by athletes and workers may exert a protective effect the pathophysiological processes of exertional heat stroke, whereas others may be detrimental. While current evidence suggests that some of these practices may be leveraged as a potential countermeasure to exertional heat stroke, further research on injury-related outcomes in humans is required.

ABSTRACT

Exertional heat stroke (EHS) is a life-threatening illness and an enduring problem among athletes, military servicemen and -women, and occupational labourers who regularly perform strenuous activity, often under hot and humid conditions or when wearing personal protective equipment. Risk factors for EHS and mitigation strategies have generally focused on the environment, health status, clothing, heat acclimatization and aerobic conditioning, but the potential role of nutrition is largely underexplored. Various nutritional and dietary strategies have shown beneficial effects on exercise performance and health and are widely used by athletes and other physically active populations. There is also evidence that some of these practices may dampen the pathophysiological features of EHS, suggesting possible protection or abatement of injury severity. Promising candidates include carbohydrate ingestion, appropriate fluid intake and glutamine supplementation. Conversely, some nutritional factors and low energy availability may facilitate the development of EHS, and individuals should be cognizant of these. Therefore, the aims of this review are to present an overview of EHS along with its mechanisms and pathophysiology, discuss how selected nutritional considerations may influence EHS risk focusing on their impact on the key pathophysiological processes of EHS, and provide recommendations for future research. With climate change expected to increase EHS risk and incidence in the coming years, further investigation on how diet and nutrition may be optimized to protect against EHS would be highly beneficial.

Quercetin Attenuates Quinocetone-Induced Cell Apoptosis In Vitro by Activating the P38/Nrf2/HO-1 Pathway and Inhibiting the ROS/Mitochondrial Apoptotic Pathway

Quinocetone (QCT), a member of the quinoxaline 1,4-di-N-oxides (QdNOs) family, can cause genotoxicity and hepatotoxicity, however, the precise molecular mechanisms of QCT are unclear. This present study investigated the protective effect of quercetin on QCT-induced cytotoxicity and the underlying molecular mechanisms in human L02 and HepG2 cells. The results showed that quercetin treatment (at 7.5–30 μM) significantly improved QCT-induced cytotoxicity and oxidative damage in human L02 and HepG2 cells. Meanwhile, quercetin treatment at 30 μM significantly inhibited QCT-induced loss of mitochondrial membrane potential, an increase in the expression of the CytC protein and the Bax/Bcl-2 ratio, and an increase in caspases-9 and -3 activity, and finally improved cell apoptosis. Quercetin pretreatment promoted the expression of the phosphorylation of p38, Nrf2, and HO-1 proteins. Pharmacological inhibition of p38 significantly inhibited quercetin-mediated activation of the Nrf2/HO-1 pathway. Consistently, pharmacological inhibitions of the Nrf2 or p38 pathways both promoted QCT-induced cytotoxicity and partly abolished the protective effects of quercetin. In conclusion, for the first time, our results reveal that quercetin could improve QCT-induced cytotoxicity and apoptosis by activating the p38/Nrf2/HO-1 pathway and inhibiting the ROS/mitochondrial apoptotic pathway. Our study highlights that quercetin may be a promising candidate for preventing QdNOs-induced cytotoxicity in humans or animals.

Changes in Specific Biomarkers Indicate Cardiac Adaptive and Anti-inflammatory Response of Repeated Recreational SCUBA Diving

Objective

Recreational SCUBA (rSCUBA) diving has become a highly popular and widespread sport. Yet, information on molecular events underlying (patho)physiological events that follow exposure to the specific environmental conditions (hyperbaric conditions, coldness, immersion, and elevated breathing pressure), in which rSCUBA diving is performed, remain largely unknown. Our previous study suggested that repeated rSCUBA diving triggers an adaptive response of cardiovascular and immune system. To elucidate further molecular events underlying cardiac and immune system adaptation and to exclude possible adverse effects we measured blood levels of specific cardiac and inflammation markers.

Methods

This longitudinal intervention study included fourteen recreational divers who performed five dives, one per week, on the depth 20–30 m that lasted 30 min, after the non-dive period of 5 months. Blood samples were taken immediately before and after the first, third, and fifth dives. Copeptin, immunoglobulins A, G and M, complement components C3 and C4, and differential blood count parameters, including neutrophil-to-lymphocyte ratio (NLR) were determined using standard laboratory methods. Cell-free DNA was measured by qPCR analysis and N-glycans released from IgG and total plasma proteins (TPP), were analyzed by hydrophilic interaction ultra-performance liquid chromatography.

Results

Copeptin level increased after the first dive but decreased after the third and fifth dive. Increases in immunoglobulins level after every dive and during whole studied period were observed, but no changes in C3, C4, and cfDNA level were detected. NLR increased only after the first dive. IgG and TPP N-glycosylation alterations toward anti-inflammatory status over whole studied period were manifested as an increase in monogalyctosylated and core-fucosylated IgG N-glycans and decrease in agalactosylated TPP N-glycans.

Conclusion

rSCUBA diving practiced on a regular basis promotes anti-inflammatory status thus contributing cardioprotection and conferring multiple health benefits.

State of Knowledge on Molecular Adaptations to Exercise in Humans: Historical Perspectives and Future Directions

For centuries, regular exercise has been acknowledged as a potent stimulus to promote, maintain, and restore healthy functioning of nearly every physiological system of the human body. With advancing understanding of the complexity of human physiology, continually evolving methodological possibilities, and an increasingly dire public health situation, the study of exercise as a preventative or therapeutic treatment has never been more interdisciplinary, or more impactful. During the early stages of the NIH Common Fund Molecular Transducers of Physical Activity Consortium (MoTrPAC) Initiative, the field is well-positioned to build substantially upon the existing understanding of the mechanisms underlying benefits associated with exercise. Thus, we present a comprehensive body of the knowledge detailing the current literature basis surrounding the molecular adaptations to exercise in humans to provide a view of the state of the field at this critical juncture, as well as a resource for scientists bringing external expertise to the field of exercise physiology. In reviewing current literature related to molecular and cellular processes underlying exercise-induced benefits and adaptations, we also draw attention to existing knowledge gaps warranting continued research effort. © 2021 American Physiological Society. Compr Physiol 12:3193-3279, 2022.

Healthy values and de novo domestication of sand rice (Agriophyllum squarrosum), a comparative view against Chenopodium quinoa

Sand rice (Agriophyllum squarrosum) is prized for its well-balanced nutritional properties, broad adaptability in Central Asia and highly therapeutic potentials. It has been considered as a potential climate-resilient crop. Its seed has comparable metabolite profile with Chenopodium quinoa and is rich in proteins, essential amino acids, minerals, polyunsaturated fatty acids, and phenolics, but low in carbohydrates. Phenolics like protocatechuic acid and quercetins have been characterized with biological functions on regulation of lipid and glucose metabolism in addition to anti-inflammatory and antioxidant activities. Sand rice is thus an important source for developing functional and nutraceutical products. Though historical consumption has been over 1300 years, sand rice has undergone few agronomic improvements until recently. Breeding by individual selection has been performed and yield of the best genotype can reach up to 1295.5 kg/ha. Furthermore, chemical mutagenesis has been used to modify the undesirable traits and a case study of a dwarf line (dwarf1), which showed the Green Revolution-like phenotypes, is presented. Utilization of both breeding methodologies will accelerate its domestication process. As a novel crop, sand rice research is rather limited compared with quinoa. More scientific input is urgently required if the nutritional and commercial potentials are to be fully realized.

New horizons in the roles and associations of COX-2 and novel natural inhibitors in cardiovascular diseases

Age-related cardiovascular disease is the leading cause of death in elderly populations. Coxibs, including celecoxib, valdecoxib, etoricoxib, parecoxib, lumiracoxib, and rofecoxib, are selective cyclooxygenase-2 (COX-2) inhibitors used to treat osteoarthritis and rheumatoid arthritis. However, many coxibs have been discontinued due to adverse cardiovascular events. COX-2 contains cyclooxygenase (COX) and peroxidase (POX) sites. COX-2 inhibitors block COX activity without affecting POX activity. Recently, quercetin-like flavonoid compounds with OH groups in their B-rings have been found to serve as activators of COX-2 by binding the POX site. Galangin-like flavonol compounds serve as inhibitors of COX-2. Interestingly, nabumetone, flurbiprofen axetil, piketoprofen-amide, and nepafenac are ester prodrugs that inhibit COX-2. The combination of galangin-like flavonol compounds with these prodrug metabolites may lead to the development of novel COX-2 inhibitors. This review focuses on the most compelling evidence regarding the role and mechanism of COX-2 in cardiovascular diseases and demonstrates that quercetin-like compounds exert potential cardioprotective effects by serving as cofactors of COX-2.

Natural Polyphenols as Immunomodulators to Rescue Immune Response Homeostasis: Quercetin as a Research Model against Severe COVID-19

The COVID-19 pandemic is caused by SARS-CoV-2 and is leading to the worst health crisis of this century. It emerged in China during late 2019 and rapidly spread all over the world, producing a broad spectrum of clinical disease severity, ranging from asymptomatic infection to death (4.3 million victims so far). Consequently, the scientific research is devoted to investigating the mechanisms of COVID-19 pathogenesis to both identify specific therapeutic drugs and develop vaccines. Although immunological mechanisms driving COVID-19 pathogenesis are still largely unknown, new understanding has emerged about the innate and adaptive immune responses elicited in SARS-CoV-2 infection, which are mainly focused on the dysregulated inflammatory response in severe COVID-19. Polyphenols are naturally occurring products with immunomodulatory activity, playing a relevant role in reducing inflammation and preventing the onset of serious chronic diseases. Mainly based on data collected before the appearance of SARS-CoV-2, polyphenols have been recently suggested as promising agents to fight COVID-19, and some clinical trials have already been approved with polyphenols to treat COVID-19. The aim of this review is to analyze and discuss the in vitro and in vivo research on the immunomodulatory activity of quercetin as a research model of polyphenols, focusing on research that addresses issues related to the dysregulated immune response in severe COVID-19. From this analysis, it emerges that although encouraging data are present, they are still insufficient to recommend polyphenols as potential immunomodulatory agents against COVID-19.

Does Flavonoid Consumption Improve Exercise Performance? Is It Related to Changes in the Immune System and Inflammatory Biomarkers? A Systematic Review of Clinical Studies since 2005

Flavonoids are attracting increasing attention due to their antioxidant, cardioprotective, and immunomodulatory properties. Nevertheless, little is known about their role in exercise performance in association with immune function. This systematic review firstly aimed to shed light on the ergogenic potential of flavonoids. A search strategy was run using SCOPUS database. The returned studies were screened by prespecified eligibility criteria, including intervention lasting at least one week and performance objectively quantified, among others. Fifty-one studies (54 articles) met the inclusion criteria, involving 1288 human subjects, either physically untrained or trained. Secondly, we aimed to associate these studies with the immune system status. Seventeen of the selected studies (18 articles) assessed changes in the immune system. The overall percentage of studies reporting an improved exercise performance following flavonoid supplementation was 37%, the proportion being 25% when considering quercetin, 28% for flavanol-enriched extracts, and 54% for anthocyanins-enriched extracts. From the studies reporting an enhanced performance, only two, using anthocyanin supplements, focused on the immune system and found certain anti-inflammatory effects of these flavonoids. These results suggest that flavonoids, especially anthocyanins, may exert beneficial effects for athletes’ performances, although further studies are encouraged to establish the optimal dosage and to clarify their impact on immune status.

8-Week Supplementation of 2S-Hesperidin Modulates Antioxidant and Inflammatory Status after Exercise until Exhaustion in Amateur Cyclists

Both acute and chronic ingestion of 2S-hesperidin have shown antioxidant and anti-inflammatory effects in animal studies, but so far, no one has studied this effect of chronic ingestion in humans. The main objective was to evaluate whether an 8-week intake of 2S-hesperidin had the ability to modulate antioxidant-oxidant and inflammatory status in amateur cyclists. A parallel, randomized, double-blind, placebo-controlled trial study was carried out with two groups (500 mg/d 2S-hesperidin; n = 20 and 500 mg/d placebo; n = 20). An incremental test was performed to determine the working zones in a rectangular test, which was used to analyze for changes in antioxidant and inflammatory biomarkers. After 2S-hesperidin ingestion, we found in the rectangular test: (1) an increase in superoxide dismutase (SOD) after the exercise phase until exhaustion (p = 0.045) and the acute recovery phase (p = 0.004), (2) a decrease in the area under the oxidized glutathione curve (GSSG) (p = 0.016), and (3) a decrease in monocyte chemoattractant protein 1 (MCP1) after the acute recovery phase (p = 0.004), post-intervention. Chronic 2S-hesperidin supplementation increased endogenous antioxidant capacity (↑SOD) after maximal effort and decreased oxidative stress (↓AUC-GSSG) during the rectangular test, decreasing inflammation (↓MCP1) after the acute recovery phase.

Phytonutrient and Nutraceutical Action against COVID-19: Current Review of Characteristics and Benefits

The trend toward using phytonutrients and/or nutraceuticals (P/Ns) with the aim of impacting immune health has increased in recent years. The main reason is that properties of P/Ns are associated with possible immunomodulating effects in the prevention and complementary treatment of viral diseases, including COVID-19 and other respiratory infections. In the present review, we assess the scientific plausibility of specific P/Ns for this purpose of preventative and therapeutic interventions against COVID-19, with an emphasis on safety, validity, and evidence of efficacy against other viruses. Five potential candidates have been identified after reviewing available studies (in silico, in vitro, and in vivo) in which certain flavonoids have demonstrated a potential for use as adjuvant therapeutic agents against viral infections, including COVID-19. As these are often better tolerated than pharmacological treatments, their use could be more widely considered if additional detailed studies can validate the existing evidence.

Quercetin: Antiviral Significance and Possible COVID-19 Integrative Considerations

Quercetin, a naturally occurring dietary flavonoid, is well known to ameliorate chronic diseases and aging processes in humans, and its antiviral properties have been investigated in numerous studies. In silico and in vitro studies demonstrated that quercetin can interfere with various stages of the coronavirus entry and replication cycle such as PLpro, 3CLpro, and NTPase/helicase. Due to its pleiotropic activities and lack of systemic toxicity, quercetin and its derivatives may represent target compounds to be tested in future clinical trials to enrich the drug arsenal against coronavirus infections. There is evidence that quercetin in combination with, for example, vitamins C and D, may exert a synergistic antiviral action that may provide either an alternative or additional therapeutic/preventive option due to overlapping antiviral and immunomodulatory properties. This review summarizes the antiviral significance of quercetin and proposes a possible strategy for the effective utilization of natural polyphenols in our daily diet for the prevention of viral infection.

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.

The Physiologic Activity and Mechanism of Quercetin-Like Natural Plant Flavonoids

The term "vitamin P" is an old but interesting concept. Most substances in this category belong to the family of flavonoids. "Vitamin P" has also been used to define the activity of some flavonoids, including quercetin, myricetin, and rutin. According to experimental studies, the "quercetin-like natural plant flavonoids" are beneficial to the body due to their various physiological and pharmacological activities in large doses (5 μM in vitro, 50 mg/kg in mice and 100 mg/kg in rats). The physiologically achievable concentration is 10 to 100 nM, which is quite high and hard to achieve from a normal diet. Thus, the physiologic activity and mechanism of "vitamin P" are still not clear. It should be noted that the quercetin-like natural plant flavonoids are physiological co-factors of cyclooxygenases (COXs), which are the rate-limiting key enzymes of prostaglandins. These quercetin-like natural plant flavonoids can strongly stimulate prostaglandin levels at lower doses (10 nM in vitro and in 0.1 mg/kg in vivo in rats). Although these "vitamin P" substances are not original substances in the body, their physiological functions affect the body. This review is focused on the most compelling evidence regarding the physiologic role and mechanism of quercetin-like natural plant flavonoids, which may be useful in understanding the physiological functions of "vitamin P", with the goal of focusing on the role of flavonoids in human physiological health.

Nutritional interventions for reducing the signs and symptoms of exercise-induced muscle damage and accelerate recovery in athletes: current knowledge, practical application and future perspectives

PURPOSE

This review provides an overview of the current knowledge of the nutritional strategies to treat the signs and symptoms related to EIMD. These strategies have been organized into the following sections based upon the quality and quantity of the scientific support available: (1) interventions with a good level of evidence; (2) interventions with some evidence and require more research; and (3) potential nutritional interventions with little to-no-evidence to support efficacy.

METHOD

Pubmed, EMBASE, Scopus and Web of Science were used. The search terms 'EIMD' and 'exercise-induced muscle damage' were individually concatenated with 'supplementation', 'athletes', 'recovery', 'adaptation', 'nutritional strategies', hormesis'.

RESULT

Supplementation with tart cherries, beetroot, pomegranate, creatine monohydrate and vitamin D appear to provide a prophylactic effect in reducing EIMD. β-hydroxy β-methylbutyrate, and the ingestion of protein, BCAA and milk could represent promising strategies to manage EIMD. Other nutritional interventions were identified but offered limited effect in the treatment of EIMD; however, inconsistencies in the dose and frequency of interventions might account for the lack of consensus regarding their efficacy.

CONCLUSION

There are clearly varying levels of evidence and practitioners should be mindful to refer to this evidence-base when prescribing to clients and athletes. One concern is the potential for these interventions to interfere with the exercise-recovery-adaptation continuum. Whilst there is no evidence that these interventions will blunt adaptation, it seems pragmatic to use a periodised approach to administering these strategies until data are in place to provide and evidence base on any interference effect on adaptation.

Quercetin and Vitamin C: An Experimental, Synergistic Therapy for the Prevention and Treatment of SARS-CoV-2 Related Disease (COVID-19)

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) represents an emergent global threat which is straining worldwide healthcare capacity. As of May 27th, the disease caused by SARS-CoV-2 (COVID-19) has resulted in more than 340,000 deaths worldwide, with 100,000 deaths in the US alone. It is imperative to study and develop pharmacological treatments suitable for the prevention and treatment of COVID-19. Ascorbic acid is a crucial vitamin necessary for the correct functioning of the immune system. It plays a role in stress response and has shown promising results when administered to the critically ill. Quercetin is a well-known flavonoid whose antiviral properties have been investigated in numerous studies. There is evidence that vitamin C and quercetin co-administration exerts a synergistic antiviral action due to overlapping antiviral and immunomodulatory properties and the capacity of ascorbate to recycle quercetin, increasing its efficacy. Safe, cheap interventions which have a sound biological rationale should be prioritized for experimental use in the current context of a global health pandemic. We present the current evidence for the use of vitamin C and quercetin both for prophylaxis in high-risk populations and for the treatment of COVID-19 patients as an adjunct to promising pharmacological agents such as Remdesivir or convalescent plasma.

Electroacupuncture Mimics Exercise-Induced Changes in Skeletal Muscle Gene Expression in Women With Polycystic Ovary Syndrome

CONTEXT

Autonomic nervous system activation mediates the increase in whole-body glucose uptake in response to electroacupuncture but the mechanisms are largely unknown.

OBJECTIVE

To identify the molecular mechanisms underlying electroacupuncture-induced glucose uptake in skeletal muscle in insulin-resistant overweight/obese women with and without polycystic ovary syndrome (PCOS).

DESIGN/PARTICIPANTS

In a case-control study, skeletal muscle biopsies were collected from 15 women with PCOS and 14 controls before and after electroacupuncture. Gene expression and methylation was analyzed using Illumina BeadChips arrays.

RESULTS

A single bout of electroacupuncture restores metabolic and transcriptional alterations and induces epigenetic changes in skeletal muscle. Transcriptomic analysis revealed 180 unique genes (q < 0.05) whose expression was changed by electroacupuncture, with 95% of the changes towards a healthier phenotype. We identified DNA methylation changes at 304 unique sites (q < 0.20), and these changes correlated with altered expression of 101 genes (P < 0.05). Among the 50 most upregulated genes in response to electroacupuncture, 38% were also upregulated in response to exercise. We identified a subset of genes that were selectively altered by electroacupuncture in women with PCOS. For example, MSX1 and SRNX1 were decreased in muscle tissue of women with PCOS and were increased by electroacupuncture and exercise. siRNA-mediated silencing of these 2 genes in cultured myotubes decreased glycogen synthesis, supporting a role for these genes in glucose homeostasis.

CONCLUSION

Our findings provide evidence that electroacupuncture normalizes gene expression in skeletal muscle in a manner similar to acute exercise. Electroacupuncture might therefore be a useful way of assisting those who have difficulties performing exercise.

Effects of exercise training and detraining on atheromatous matrix metalloproteinase activity in mice

BACKGROUND AND AIMS

Exercise training (ET) helps treat atherosclerosis. However, many patients stop regular ET for various reasons. The effect of detraining on atherosclerosis is not well studied. We examined the effects of ET vs. short-term detraining on atheromatous matrix-metalloproteinase (MMP) activity in preexisting plaque and circulating cytokines/lipids.

METHODS AND RESULTS

Eighteen-week-old apolipoprotein-E^-/- mice (n = 56) on a Western diet underwent: 1) ET for 6-weeks (ET5+1), 2) ET for 5-weeks and detraining for 1-week (ET5+0), 3) ET for the last 1-week (ET0+1), or 4) no treadmill ET at all for 6-weeks (ET0+0). Atheromatous MMP-activity was visualized using molecular imaging with an MMP-2/9-activatable near-infrared-fluorescent probe. Compared with no ET (ET0+0), regular ET (ET5+1) decreased carotid atheromatous MMP activity, but this protective effect was significantly blunted by short-term detraining (ET5+0). Short-term detraining after longer-term ET showed a reduction in MMP-activity similar to short-term ET (ET0+1). Blood levels of lipids and cytokines paralleled the molecular imaging results: exercise caused higher levels of high-density lipoprotein, adiponectin, and interleukin-10 and lower levels of vascular cell adhesion molecule, monocyte chemoattractant protein-1, interleukin-1β, and low-density lipoprotein. However, this beneficial effect was short-lived, with the ET5+0 group being similar to the ET0+0 group, and the ET0+1 group being similar to the ET5+1 group. The effect of exercise can be modeled with an exponential-decay of the protective factor of about 15%/day.

CONCLUSIONS

Even short-term detraining reduces atheroprotective effects, and tips the balance towards atherosclerosis. This suggests that ET, to be effective, needs to be prolonged and regular, and that detraining should be avoided.

Mixed Flavonoid Supplementation Attenuates Postexercise Plasma Levels of 4-Hydroxynonenal and Protein Carbonyls in Endurance Athletes

This double-blinded, placebo controlled, randomized crossover trial investigated the influence of 2-week mixed flavonoid versus placebo supplementation on oxinflammation markers after a 75-km cycling time trial in 22 cyclists (42.3 ± 1.7 years). Blood samples were collected before and after the 2-week supplementation, and then 0 hr, 1.5 hr, and 21 hr post 75-km cycling (176 ± 5.4 min, 73.4 ±2.0% maximal oxygen consumption). The supplement provided 678-mg flavonoids with quercetin (200 mg), green tea catechins (368 mg, 180-mg epigallocatechin gallate), and anthocyanins (128 mg) from bilberry extract, with caffeine, vitamin C, and omega-3 fatty acids added as adjuvants. Blood samples were analyzed for blood leukocyte counts, oxinflammation biomarkers, including 4-hydroxynonenal, protein carbonyls, and peripheral blood mononuclear mRNA expression for cyclooxygenease-2 and glutathione peroxidase. Each of the blood biomarkers was elevated postexercise (time effects, all ps < .01), with lower plasma levels for 4-hydroxynonenal (at 21-hr postexercise) in flavonoid versus placebo (interaction effect, p = .008). Although elevated postexercise, no trial differences for the neutrophil/lymphocyte ratio (p = .539) or peripheral blood mononuclear mRNA expression for cyclooxygenease-2 (p = .322) or glutathione peroxidase (p = .839) were shown. Flavonoid supplementation prior to intensive exercise decreased plasma peroxidation and oxidative damage, as determined by 4-hydroxynonenal. Postexercise increases were similar between the flavonoid and placebo trials for peripheral blood mononuclear mRNA expression for cyclooxygenease-2 and the nuclear factor erythroid 2-related factor 2 related gene glutathione peroxidase (NFE2L2). The data support the strategy of flavonoid supplementation to mitigate postexercise oxidative stress in endurance athletes.

Effect of Cocoa Products and Its Polyphenolic Constituents on Exercise Performance and Exercise-Induced Muscle Damage and Inflammation: A Review of Clinical Trials

In recent years, the consumption of chocolate and, in particular, dark chocolate has been "rehabilitated" due to its high content of cocoa antioxidant polyphenols. Although it is recognized that regular exercise improves energy metabolism and muscle performance, excessive or unaccustomed exercise may induce cell damage and impair muscle function by triggering oxidative stress and tissue inflammation. The aim of this review was to revise the available data from literature on the effects of cocoa polyphenols on exercise-associated tissue damage and impairment of exercise performance. To this aim, PubMed and Web of Science databases were searched with the following keywords: "intervention studies", "cocoa polyphenols", "exercise training", "inflammation", "oxidative stress", and "exercise performance". We selected thirteen randomized clinical trials on cocoa ingestion that involved a total of 200 well-trained athletes. The retrieved data indicate that acute, sub-chronic, and chronic cocoa polyphenol intake may reduce exercise-induced oxidative stress but not inflammation, while mixed results are observed in terms of exercise performance and recovery. The interpretation of available results on the anti-oxidative and anti-inflammatory activities of cocoa polyphenols remains questionable, likely due to the variety of physiological networks involved. Further experimental studies are mandatory to clarify the role of cocoa polyphenol supplementation in exercise-mediated inflammation.

Changes in Parameters of Oxidative Stress, Immunity, and Behavior in Endurance Athletes During a Preparation Period in Winter

Michalickova, D, Minic, R, Kotur-Stevuljevic, J, Andjelkovic, M, Dikic, N, Kostic-Vucicevic, M, Slanar, O, and Djordjevic, B. Changes in parameters of oxidative stress, immunity, and behavior in endurance athletes during a preparation period in winter. J Strength Cond Res 34(10): 2965-2973, 2020-The current study monitored markers of immunological and oxidative status in 9 male elite endurance athletes: V[Combining Dot Above]O2max: 68 ± 11 ml·kg·min, age: 24 ± 2.5 years, and training loads: 128 ± 21 metabolic equivalents-h·wk during a 3-month preparation period in winter (January-March). Self-rated state of moods evaluation (by Profile of Mood States questionnaire) was performed, and blood samples were collected at the beginning and end of the study. Spectrophotometric methods and enzyme-linked immunosorbent assay were used for parameters' determination. The level of concanavalin A (ConA)-stimulated interferon-γ (IFN-γ) from peripheral blood mononuclear cells (PBMCs) was increased (562 [147-852] vs. 1,097 [451-1842] pg·ml, p = 0.013). Also, the level of transforming growth factor-1 (TGF-β1) in serum was elevated (2.5 [1.4-5.1] vs. 7.2 [4.9-8.2] ng·ml, p = 0.015). There was no change in the level of peptidoglycan (PGN)-stimulated interleukin (IL)-10 from PBMCs. There were no significant changes in PBMCs proliferation/viability on stimulation with ConA and PGN during the study. No changes in superoxide dismutase, prooxidative-antioxidative balance, total oxidant status (TOS), and thiobarbituric acid reactive substances were observed along the study. Total antioxidant status (TAS) was increased (910 ± 174 vs. 1,090 ± 102 μmol·L, p = 0.018), and activity of paraoxonase (PON1) was decreased (523 ± 295 vs. 335 ± 183 U·L, p = 0.003) at the end of the study. Advanced oxidation protein products were increased (25 ± 7.9 vs. 42 ± 7.6 μmol·L, p = 0.011). The self-rated sense of vigor significantly declined (20 ± 2.1 vs. 14 ± 3.4, p = 0.045). In conclusion, 3 months of regular training in winter induced prominent changes in cytokines, biomarkers of oxidative stress, and antioxidative enzyme activity. These changes might increase susceptibility of athletes to disease and muscle damage and consequently lead to performance reduction.

Exercise-induced muscle damage: What is it, what causes it and what are the nutritional solutions?

Exercise-induced muscle damage (EIMD) is characterized by symptoms that present both immediately and for up to 14 days after the initial exercise bout. The main consequence of EIMD for the athlete is the loss of skeletal muscle function and soreness. As such, numerous nutrients and functional foods have been examined for their potential to ameliorate the effects of EIMD and accelerate recovery, which is the purpose of many nutritional strategies for the athlete. However, the trade-off between recovery and adaptation is rarely considered. For example, many nutritional interventions described in this review target oxidative stress and inflammation, both thought to contribute to EIMD but are also crucial for the recovery and adaptation process. This calls into question whether long term administration of supplements and functional foods used to target EIMD is indeed best practice. This rapidly growing area of sports nutrition will benefit from careful consideration of the potential hormetic effect of long term use of nutritional aids that ameliorate muscle damage. This review provides a concise overview of what EIMD is, its causes and consequences and critically evaluates potential nutritional strategies to ameliorate EIMD. We present a pragmatic practical summary that can be adopted by practitioners and direct future research, with the purpose of pushing the field to better consider the fine balance between recovery and adaptation and the potential that nutritional interventions have in modulating this balance.

Critical Evaluation of Gene Expression Changes in Human Tissues in Response to Supplementation with Dietary Bioactive Compounds: Moving Towards Better-Quality Studies

Pre-clinical cell and animal nutrigenomic studies have long suggested the modulation of the transcription of multiple gene targets in cells and tissues as a potential molecular mechanism of action underlying the beneficial effects attributed to plant-derived bioactive compounds. To try to demonstrate these molecular effects in humans, a considerable number of clinical trials have now explored the changes in the expression levels of selected genes in various human cell and tissue samples following intervention with different dietary sources of bioactive compounds. In this review, we have compiled a total of 75 human studies exploring gene expression changes using quantitative reverse transcription PCR (RT-qPCR). We have critically appraised the study design and methodology used as well as the gene expression results reported. We herein pinpoint some of the main drawbacks and gaps in the experimental strategies applied, as well as the high interindividual variability of the results and the limited evidence supporting some of the investigated genes as potential responsive targets. We reinforce the need to apply normalized procedures and follow well-established methodological guidelines in future studies in order to achieve improved and reliable results that would allow for more relevant and biologically meaningful results.

Metabolic recovery from heavy exertion following banana compared to sugar beverage or water only ingestion: A randomized, crossover trial

Objectives and methods

Using a randomized, crossover, counterbalanced approach, cyclists (N = 20, overnight fasted state) engaged in the four 75-km time trials (2-week washout) while ingesting two types of bananas with similar carbohydrate (CHO) but different phenolic content (Cavendish, CAV; mini-yellow, MIY, 63% higher polyphenols), a 6% sugar beverage (SUG), and water only (WAT). CHO intake was set at 0.2 g/kg every 15 minutes. Blood samples were collected pre-exercise and 0 h-, 0.75 h-,1.5 h-, 3 h-, 4.5 h-, 21 h-, 45 h-post-exercise.

Results

Each of the CHO trials (CAV, MIY, SUG) compared to water was associated with higher post-exercise plasma glucose and fructose, and lower leukocyte counts, plasma 9+13 HODES, and IL-6, IL-10, and IL-1ra. OPLS-DA analysis showed that metabolic perturbation (N = 1,605 metabolites) for WAT (86.8±4.0 arbitrary units) was significantly greater and sustained than for CAV (70.4±3.9, P = 0.006), MIY (68.3±4.0, P = 0.002), and SUG (68.1±4.2, P = 0.002). VIP ranking (<3.0, N = 25 metabolites) showed that both CAV and MIY were associated with significant fold changes in metabolites including those from amino acid and xenobiotics pathways. OPLS-DA analysis of immediate post-exercise metabolite shifts showed a significant separation of CAV and MIY from both WAT and SUG (R2Y = 0.848, Q2Y = 0.409). COX-2 mRNA expression was lower in both CAV and MIY, but not SUG, versus WAT at 21-h post-exercise in THP-1 monocytes cultured in plasma samples. Analysis of immediate post-exercise samples showed a decrease in LPS-stimulated THP-1 monocyte extracellular acidification rate (ECAR) in CAV and MIY, but not SUG, compared to WAT.

Conclusions

CHO ingestion from bananas or a sugar beverage had a comparable influence in attenuating metabolic perturbation and inflammation following 75-km cycling. Ex-vivo analysis with THP-1 monocytes supported a decrease in COX-2 mRNA expression and reduced reliance on glycolysis for ATP production following ingestion of bananas but not sugar water when compared to water alone.

Trial registration

ClinicalTrials.gov, U.S. National Institutes of Health, identifier: NCT02994628

Putative mechanisms of kiwifruit on maintenance of normal gastrointestinal function

Kiwifruits are recognized as providing relief from constipation and symptoms of constipation-predominant irritable bowel syndrome (IBS-C). However, the underlying mechanisms, specifically in regards to gastrointestinal transit time and motility, are still not completely understood. This review provides an overview on the physiological and pathophysiological processes underlying constipation and IBS-C, the composition of kiwifruit, and recent advances in the research of kiwifruit and abdominal comfort. In addition, gaps in the research are highlighted and scientific studies of other foods with known effects on the gastrointestinal tract are consulted to find likely mechanisms of action. While the effects of kiwifruit fiber are well documented, observed increases in gastrointestinal motility caused by kiwifruit are not fully characterized. There are a number of identified mechanisms that may be activated by kiwifruit compounds, such as the induction of motility via protease-activated signaling, modulation of microflora, changes in colonic methane status, bile flux, or mediation of inflammatory processes.

Quercetin and Green Tea Extract Supplementation Downregulates Genes Related to Tissue Inflammatory Responses to a 12-Week High Fat-Diet in Mice

Quercetin (Q) and green tea extract (E) are reported to counter insulin resistance and inflammation and favorably alter fat metabolism. We investigated whether a mixture of E + Q (EQ) could synergistically influence metabolic and inflammation endpoints in a high-fat diet (HFD) fed to mice. Male C57BL/6 mice (n = 40) were put on HFD (fat = 60%kcal) for 12 weeks and randomly assigned to Q (25 mg/kg of body weight (BW)/day), E (3 mg of epigallocatechin gallate/kg BW/day), EQ, or control groups for four weeks. At 16 weeks, insulin sensitivity was measured via the glucose tolerance test (GTT), followed by area-under-the-curve (AUC) estimations. Plasma cytokines and quercetin were also measured, along with whole genome transcriptome analysis and real-time polymerase chain reaction (qPCR) on adipose, liver, and skeletal muscle tissues. Univariate analyses were conducted via analysis of variance (ANOVA), and whole-genome expression profiles were examined via gene set enrichment. At 16 weeks, plasma quercetin levels were higher in Q and EQ groups vs. the control and E groups (p < 0.05). Plasma cytokines were similar among groups (p > 0.05). AUC estimations for GTT was 14% lower for Q vs. E (p = 0.0311), but non-significant from control (p = 0.0809). Genes for cholesterol metabolism and immune and inflammatory response were downregulated in Q and EQ groups vs. control in adipose tissue and soleus muscle tissue. These data support an anti-inflammatory role for Q and EQ, a result best captured when measured with tissue gene downregulation in comparison to changes in plasma cytokine levels.

Muscle damage and inflammation during recovery from exercise

Unaccustomed exercise consisting of eccentric (i.e., lengthening) muscle contractions often results in muscle damage characterized by ultrastructural alterations in muscle tissue, clinical signs, and symptoms (e.g., reduced muscle strength and range of motion, increased muscle soreness and swelling, efflux of myocellular proteins). The time course of recovery following exercise-induced muscle damage depends on the extent of initial muscle damage, which in turn is influenced by the intensity and duration of exercise, joint angle/muscle length, and muscle groups used during exercise. The effects of these factors on muscle strength, soreness, and swelling are well characterized. By contrast, much less is known about how they affect intramuscular inflammation and molecular aspects of muscle adaptation/remodeling. Although inflammation has historically been viewed as detrimental for recovery from exercise, it is now generally accepted that inflammatory responses, if tightly regulated, are integral to muscle repair and regeneration. Animal studies have revealed that various cell types, including neutrophils, macrophages, mast cells, eosinophils, CD8 and T-regulatory lymphocytes, fibro-adipogenic progenitors, and pericytes help to facilitate muscle tissue regeneration. However, more research is required to determine whether these cells respond to exercise-induced muscle damage. A large body of research has investigated the efficacy of physicotherapeutic, pharmacological, and nutritional interventions for reducing the signs and symptoms of exercise-induced muscle damage, with mixed results. More research is needed to examine if/how these treatments influence inflammation and muscle remodeling during recovery from exercise.

Recovery of the immune system after exercise

The notion that prolonged, intense exercise causes an "open window" of immunodepression during recovery after exercise is well accepted. Repeated exercise bouts or intensified training without sufficient recovery may increase the risk of illness. However, except for salivary IgA, clear and consistent markers of this immunodepression remain elusive. Exercise increases circulating neutrophil and monocyte counts and reduces circulating lymphocyte count during recovery. This lymphopenia results from preferential egress of lymphocyte subtypes with potent effector functions [e.g., natural killer (NK) cells, γδ T cells, and CD8⁺ T cells]. These lymphocytes most likely translocate to peripheral sites of potential antigen encounter (e.g., lungs and gut). This redeployment of effector lymphocytes is an integral part of the physiological stress response to exercise. Current knowledge about changes in immune function during recovery from exercise is derived from assessment at the cell population level of isolated cells ex vivo or in blood. This assessment can be biased by large changes in the distribution of immune cells between blood and peripheral tissues during and after exercise. Some evidence suggests that reduced immune cell function in vitro may coincide with changes in vivo and rates of illness after exercise, but more work is required to substantiate this notion. Among the various nutritional strategies and physical therapies that athletes use to recover from exercise, carbohydrate supplementation is the most effective for minimizing immune disturbances during exercise recovery. Sleep is an important aspect of recovery, but more research is needed to determine how sleep disruption influences the immune system of athletes.

Diet and Inflammation in Alzheimer's Disease and Related Chronic Diseases: A Review

Inflammation is one of the pathological features of the neurodegenerative disease, Alzheimer's disease (AD). A number of additional disorders are likewise associated with a state of chronic inflammation, including obesity, cardiovascular disease, and type-2 diabetes, which are themselves risk factors for AD. Dietary components have been shown to modify the inflammatory process at several steps of the inflammatory pathway. This review aims to evaluate the published literature on the effect of consumption of pro- or anti-inflammatory dietary constituents on the severity of both AD pathology and related chronic diseases, concentrating on the dietary constituents of flavonoids, spices, and fats. Diet-based anti-inflammatory components could lead to the development of potent novel anti-inflammatory compounds for a range of diseases. However, further work is required to fully characterize the therapeutic potential of such compounds, including gaining an understanding of dose-dependent relationships and limiting factors to effectiveness. Nutritional interventions utilizing anti-inflammatory foods may prove to be a valuable asset in not only delaying or preventing the development of age-related neurodegenerative diseases such as AD, but also treating pre-existing conditions including type-2 diabetes, cardiovascular disease, and obesity.

Effect of a four-week exercise program on the secretion of IFN-γ, TNF-α, IL-2 and IL-6 cytokines in elite Taekwondo athletes

The aim of the present study was to examine how a 4-week exercise program affects the serum levels of certain cytokines in Taekwondo athletes. The study involved 10 elite male Taekwondo athletes (mean age, 20.67±0.24 years; mean weight, 65.45±1.69 kg) who were studying at the Physical Education and Sports High School of Selçuk University (Konya, Turkey) in June 2014. The subjects were involved in a Taekwondo exercise program on every weekday for 4 weeks. The subjects were also engaged in an exercise to exhaustion session twice; once before starting the 4-week exercise program and once upon completion of the program. Blood samples were collected from the subjects in four rounds: During rest, upon fatigue, and before and after the 4-week exercise program. These samples were analyzed to establish the serum levels of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin (IL)-2 and IL-6 using enzyme-linked immunosorbent assay test kits. Pre- and post-exercise program, the IFN-γ and TNF-α levels did not show any significant difference. When compared with the pre-exercise levels, serum IL-2 levels of the subjects were found to be elevated after the 4-week exercise program. The highest serum IL-6 values were established after the subjects were exercised to fatigue before the exercise program was initiated (P<0.05). The 4-week exercise program resulted in a decrease in IL-6 levels (P<0.05). The findings of the study indicate that a 4-week exercise program did not result in significant changes in IFN-γ and TNF-α levels, but led to an increase in IL-2 levels. The notable finding of the present study is that a 4-week exercise program reduces cellular immune functions and, thus, the levels of IL-6, which negatively influences performance.

Quercetin Inhibits Peripheral and Spinal Cord Nociceptive Mechanisms to Reduce Intense Acute Swimming-Induced Muscle Pain in Mice

The present study aimed to evaluate the effects of the flavonoid quercetin (3,3´,4´,5,7-pentahydroxyflavone) in a mice model of intense acute swimming-induced muscle pain, which resembles delayed onset muscle soreness. Quercetin intraperitoneal (i.p.) treatment dose-dependently reduced muscle mechanical hyperalgesia. Quercetin inhibited myeloperoxidase (MPO) and N-acetyl-β-D- glucosaminidase (NAG) activities, cytokine production, oxidative stress, cyclooxygenase-2 (COX-2) and gp91^phox mRNA expression and muscle injury (creatinine kinase [CK] blood levels and myoblast determination protein [MyoD] mRNA expression) as well as inhibited NFκB activation and induced Nrf2 and HO-1 mRNA expression in the soleus muscle. Beyond inhibiting those peripheral effects, quercetin also inhibited spinal cord cytokine production, oxidative stress and glial cells activation (glial fibrillary acidic protein [GFAP] and ionized calcium-binding adapter molecule 1 [Iba-1] mRNA expression). Concluding, the present data demonstrate that quercetin is a potential molecule for the treatment of muscle pain conditions related to unaccustomed exercise.

Effect of Flavonoids on Upper Respiratory Tract Infections and Immune Function: A Systematic Review and Meta-Analysis

Previous research on animals indicates flavonoid compounds have immunomodulatory properties; however, human research remains inconclusive. The aim of this systematic review was to assess the efficacy of dietary flavonoids on upper respiratory tract infections (URTIs) and immune function in healthy adults. A created search strategy was run against Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and EMBASE classic, CINAHL, and AMED. The returned studies were initially screened, and 2 reviewers independently assessed the remaining studies for eligibility against prespecified criteria. Fourteen studies, of 387 initially identified, were included in this review, and the primary outcome measure was the effect of flavonoids on URTI incidence, duration, and severity. Of the included studies, flavonoid supplementation ranged from 0.2 to 1.2 g/d. Overall, flavonoid supplementation decreased URTI incidence by 33% (95% CI: 31%, 36%) compared with control, with no apparent adverse effects. Sick-day count was decreased by 40% with flavonoid supplementation, although unclear. Differences in bio-immune markers (e.g., interleukin-6, tumor necrosis factor-α, interferon-γ, neutrophils) were trivial between the intervention and control groups during the intervention and after exercise when a postintervention exercise bout was included. These findings suggest that flavonoids are a viable supplement to decrease URTI incidence in an otherwise healthy population.

A Phase I Dose Escalation Study Demonstrates Quercetin Safety and Explores Potential for Bioflavonoid Antivirals in Patients with Chronic Hepatitis C

The hepatitis C virus (HCV) infects more than 180 million people worldwide, with long-term consequences including liver failure and hepatocellular carcinoma. Quercetin bioflavonoids can decrease HCV production in tissue culture, in part through inhibition of heat shock proteins. If quercetin demonstrates safety and antiviral activity in patients, then it could be developed into an inexpensive HCV treatment for third world countries or other affected populations that lack financial means to cover the cost of mainstream antivirals. A phase 1 dose escalation study was performed to evaluate the safety of quercetin in 30 untreated patients with chronic HCV infection and to preliminarily characterize quercetin's potential in suppressing viral load and/or liver injury. Quercetin displayed safety in all trial participants. Additionally, 8 patients showed a "clinically meaningful" 0.41-log viral load decrease. There was a positive correlation (r = 0.41, p = 0.03) indicating a tendency for HCV decrease in patients with a lower ratio of plasma quercetin relative to dose. No significant changes in aspartate transaminase and alanine transaminase were detected. In conclusion, quercetin exhibited safety (up to 5 g daily) and there was a potential for antiviral activity in some hepatitis C patients.

Effects of vitamin D and quercetin, alone and in combination, on cardiorespiratory fitness and muscle function in physically active male adults

Introduction

Vitamin D and the antioxidant quercetin, are promising agents for improving physical performance because of their possible beneficial effects on muscular strength and cardiorespiratory fitness.

Purpose

The purpose of this study was to determine the effects of increased intakes of vitamin D, quercetin, and their combination on antioxidant status, the steroid hormone regulators of muscle function, and measures of physical performance in apparently healthy male adults engaged in moderate-to-vigorous-intensity exercise training.

Methods

A total of 40 adult male participants were randomized to either 4,000 IU vitamin D/d, 1,000 mg/d quercetin, vitamin D plus quercetin, or placebo for 8 weeks. Measures of cardiorespiratory fitness and muscle function, blood markers for antioxidant and vitamin D status, and hormones 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) and testosterone were measured pre- and postsupplementation.

Results

At enrollment, 88.6% of participants were vitamin D sufficient (serum 25-hydroxyvitamin D >50 nmol/L) and had normal serum testosterone levels. Supplementation with vitamin D significantly increased serum 25(OH)D concentration (by 87.3% in the vitamin D group, P<0.001) and was associated with an increasing trend of testosterone concentration. There were no changes in concentration of 1,25(OH)₂D₃ and markers of antioxidant status associated with vitamin D or quercetin supplementation. No improvements in physical performance measures associated with vitamin D and quercetin supplementation were found.

Conclusion

The findings obtained demonstrate that long-term vitamin D and quercetin supplementation, alone or in combination, does not improve physical performance in male adults with adequate vitamin D, testosterone, and antioxidant status.

Proinflammatory Pathways: The Modulation by Flavonoids

Inflammation is a natural, carefully orchestrated response of the organism to tissue damage, involving various signaling systems and the recruitment of inflammatory cells. These cells are stimulated to release a myriad of mediators that amplify the inflammatory response and recruit additional cells. These mediators present numerous redundancies of functions, allowing a broad and effective inflammatory response, but simultaneously make the understanding of inflammation pathways much difficult. The extent of the inflammatory response is usually self-limited, although it depends on the balance between the pro- and anti-inflammatory signals. When that equilibrium is dislocated, a more widespread inflammatory response may take place. Flavonoids have been shown to be possible alternatives to the traditionally molecules used as anti-inflammatory agents. In fact, the biological activities of flavonoids include the modulation of the diverse phases of inflammatory processes, from the gene transcription and expression to the inhibition of the enzymatic activities and the scavenging of the reactive species. In the present review, the inflammatory network is widely revised and the flavonoids' broad spectrum of action in many of the analyzed inflammatory pathways is revised. This kind of integrated revision is original in the field, providing the reader the simultaneous comprehension of the inflammatory process and the potential beneficial activities of flavonoids.

Human skeletal muscle biopsy procedures using the modified Bergström technique

The percutaneous biopsy technique enables researchers and clinicians to collect skeletal muscle tissue samples. The technique is safe and highly effective. This video describes the percutaneous biopsy technique using a modified Bergström needle to obtain skeletal muscle tissue samples from the vastus lateralis of human subjects. The Bergström needle consists of an outer cannula with a small opening ('window') at the side of the tip and an inner trocar with a cutting blade at the distal end. Under local anesthesia and aseptic conditions, the needle is advanced into the skeletal muscle through an incision in the skin, subcutaneous tissue, and fascia. Next, suction is applied to the inner trocar, the outer trocar is pulled back, skeletal muscle tissue is drawn into the window of the outer cannula by the suction, and the inner trocar is rapidly closed, thus cutting or clipping the skeletal muscle tissue sample. The needle is rotated 90° and another cut is made. This process may be repeated three more times. This multiple cutting technique typically produces a sample of 100-200 mg or more in healthy subjects and can be done immediately before, during, and after a bout of exercise or other intervention. Following post-biopsy dressing of the incision site, subjects typically resume their activities of daily living right away and can fully participate in vigorous physical activity within 48-72 hr. Subjects should avoid heavy resistance exercise for 48 hr to reduce the risk of herniation of the muscle through the incision in the fascia.

The effect of Zingiber officinale R. rhizomes (ginger) on plasma pro-inflammatory cytokine levels in well-trained male endurance runners

The aim of this study was to investigate the effect of ginger on the concentrations of plasma interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in welltrained male endurance runners. To this end, twenty-eight high-level endurance runners were randomly assigned to two groups (control and experimental). They performed the same weekly training volume for 12 weeks. The Bruce treadmill test was used three days before the start of the 12-week training period and after weeks 6 and 12 to evaluate the physiological effects of training and ginger administration. After completing the first 6-week period of exercise training protocol, two groups received 500 mg capsules of ginger powder and placebo, respectively, three times a day for the second 6-week period. Blood samples were collected before (resting blood sample) and after the Bruce treadmill test. IL-1β, IL-6 and TNF-α were assayed using standard commercial ELISA kits. Two-way repeated measures analysis of variance (ANOVA) was used to determine significant differences between control and experimental plasma IL-6, IL-1β and TNF-α concentration means of pre- and post-test periods. The IL-1β, IL-6 and TNF-α concentrations at the end of week 12/weeks 6 and 12 between two training groups were significantly different (p = 0.01, p = 0.01, and p = 0.01). In the experimental group alone, there were also significant differences in the mean IL-1β, IL-6 and TNF-α concentrations at the end of weeks 6 and 12 (p = 0.01, p = 0.01, and p = 0.01). Our findings indicated that post-exercise plasma elevations of several pro-inflammatory cytokines can be attenuated by a six-week ginger administration period.

Exercise effects on polyp burden and immune markers in the ApcMin/+ mouse model of intestinal tumorigenesis

Many observational epidemiologic studies suggest an association between exercise and colon cancer risk. The mechanisms contributing to a preventative effect of exercise on colon cancer are complex and multifaceted. Altered immune system function is one possible mechanism that has been largely unexplored. Therefore, the purpose of this study was to examine the effects of exercise on markers associated with macrophages and select T cell populations in a mouse model of intestinal tumorigenesis and to relate this to polyp characteristics. Male Apc^Min/+ mice were randomly assigned to either sedentary (Sed) or exercise (Ex) treatment (n=6–9/group). The exercise treatment consisted of treadmill running for 1 h/day and 6 days a week at 15 m/min from 4 until 16 weeks of age. Intestinal polyps were counted and categorized by size. Mucosal tissue was analyzed for mRNA expression of overall macrophages (F4/80), for genes associated with M1 (IL-12, IL-23 and Nos2) and M2 (CD206, IL-10, IL-4, CCL17, CCL22 and Arg-1) macrophages and the macrophage chemoattractants MCP-1, fetuin A and CXCL14. Markers for cytotoxic T cells (CTLs) and regulatory T cells were also examined by measuring mRNA expression of CD8 and Foxp3, respectively. While there was no significant difference in overall polyp number between the groups (Sed, 23.3±4.3; and Ex, 16.5±4.3), Ex did have a reduction in the number of large polyps (Sed, 6.1±1.1; and Ex, 3.0±0.6) (P<0.05). This was consistent with a decrease in spleen weight (P<0.05). Similarly, Ex reduced mRNA expression of overall macrophages (F4/80) as well as markers associated with both M1 (IL-12) and M2 (CD206, CCL22 and Arg-1) subtypes (P<0.05) but there was no significant decrease in macrophage chemoattractants. CD8 expression was increased while Foxp3 expression was decreased with Ex (P<0.05). Overall the data provide important new information on immune regulation as a possible mechanism for the documented benefits of exercise training on reducing colon cancer progression.

High-intensity interval training induces a modest systemic inflammatory response in active, young men

THE PURPOSE OF THIS STUDY WAS TO DETERMINE

1) the extent to which an acute session of high-intensity interval training (HIIT) increases systemic inflammatory cytokines and chemokines, and 2) whether 2 weeks of HIIT training alters the inflammatory response. Eight recreationally active males (aged 22±2 years) performed 2 weeks of HIIT on a cycle ergometer (six HIIT sessions at 8-12 intervals; 60-second intervals, 75-second active rest) at a power output equivalent to 100% of their predetermined peak oxygen uptake (VO2max). Serum samples were collected during the first and sixth HIIT sessions at rest and immediately, 15, 30, and 45 minutes post-exercise. An acute session of HIIT induced significant increases in interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor-α, and monocyte chemotactic protein-1 compared with rest. The concentrations of interferon-γ, granulocyte macrophage-colony-stimulating factor, and IL-1β were unaltered with an acute session of HIIT Two weeks of training did not alter the inflammatory response to an acute bout of HIIT exercise. Maximal power achieved during a VO2max test significantly increased 4.6%, despite no improvements in VO2max after 2 weeks of HIIT. These data suggest that HIIT exercise induces a small inflammatory response in young, recreationally active men; however, 2 weeks of HIIT does not alter this response.

Dietary strategies to recover from exercise-induced muscle damage

Exhaustive or unaccustomed intense exercise can cause exercise-induced muscle damage (EIMD) and its undesirable consequences may decrease the ability to exercise and to adhere to a training programme. This review briefly summarises the muscle damage process, focusing predominantly on oxidative stress and inflammation as contributing factors, and describes how nutrition may be positively used to recover from EIMD. The combined intake of carbohydrates and proteins and the use of antioxidants and/or anti-inflammatory nutrients within physiological ranges are interventions that may assist the recovery process. Although the works studying food instead of nutritional supplements are very scarce, their results seem to indicate that food might be a favourable option as a recovery strategy. To date, the only tested foods were milk, cherries, blueberries and pomegranate with promising results. Other potential solutions are foods rich in protein, carbohydrates, antioxidants and/or anti-inflammatory nutrients.

Nutrient Timing

As the incidence rate of lifestyle-related chronic conditions such as cardiovascular disease, obesity, and type 2 diabetes continues to increase, the importance of regular exercise and a healthy diet for improving or maintaining good health is critical. Exercise training is known to improve fitness and many health risk factors, as well as to improve the performance of competitive athletes. It has become increasingly clear, however, that nutrient intake before, during, and after exercise sessions has a powerful influence on the adaptive response to the exercise stimuli. In this review, the science behind nutrient timing will be discussed as it relates to exercise performance, recovery, and training adaptation. Evidence will be provided that validates intake of appropriate nutrients before, during, and immediately after exercise not only to improve exercise performance but also to maximize the training response. Ultimately, the combined response to exercise and proper nutrient intake leads to not only better performance in athletes but also greater health benefits for all exercisers.

Inhibitory action of quercetin on eosinophil activation in vitro

The influence of quercetin on eosinophil functions was examined in vitro and in vivo. The first set of experiments was undertaken to examine whether quercetin could suppress eosinophilia and IgE hyperproduction induced by Mesocestoides corti infection in BALB/c mice. The number of peripheral blood eosinophils and IgE levels were examined 21 days after infection. Oral administration of quercetin for 21 days could not suppress both peripheral blood eosinophilia and IgE hyperproduction, even when 20.0 mg/kg quercetin was used for treatment. The second part of the experiment was designed to examine the influence of quercetin on eosinophil activation induced by SCF stimulation in vitro. Eosinophils were obtained from M. corti-infected mice and stimulated with SCF in the presence of various concentrations of quercetin for 24 h. The addition of quercetin into cell cultures could suppress eosinophil activation induced by SCF stimulation as assessed by measuring the contents of RANTES, MIP-1β, ECP, and MBP in culture supernatants. The minimum concentration of quercetin which caused significant suppression of factor secretion was 5.0 μM. These results may suggest that quercetin will be a good candidate for the supplement on the management of eosinophil-mediated diseases, such as allergic rhinitis and asthma.

Effect of resveratrol and quercetin supplementation on redox status and inflammation after exercise

Resveratrol and quercetin function as antioxidants and anti-inflammatories in vitro, but these mechanisms have been minimally examined in combination in exercising humans. The purpose of this investigation was to examine supplementation as a countermeasure against oxidative stress and inflammation in response to exercise. Fourteen athletes were randomly assigned, in a double-blind crossover design, to a resveratrol and quercetin combination (RQ) (120 mg resveratrol and 225 mg quercetin for 6 days and 240 mg resveratrol and 450 mg quercetin on day 7 just prior to exercise) or to placebo (P). There was a 1-week washout between trials. Blood was taken at baseline, pre-exercise, immediately after exercise, and 1 h after exercise. Plasma was analyzed for oxidative stress (F2-isoprostanes and protein carbonyls), antioxidant capacity (ferric-reducing ability of plasma (FRAP), Trolox equivalent antioxidant capacity (TEAC), oxygen radical absorptive capacity (ORAC)), and inflammation (cytokine interleukin (IL)-8 and C-reactive protein (CRP)). Statistical design utilized a 2 × 3 ANOVA and Student's t test. Pre-exercise values were not different from baseline for any measure. The postexercise increase in F2-isoprostanes was significantly less (p = 0.039 interaction) with RQ (68%) than with P (137%). Protein carbonyls, FRAP, ORAC, and TEAC significantly increased after exercise but were not affected by treatment. IL-8 and CRP increased significantly immediately after exercise but were not affected by treatment. These data indicate that RQ significantly reduces exercise-induced lipid peroxidation without associated changes in inflammation or plasma antioxidant status.

Effect of flavonoids on circulating levels of TNF-α and IL-6 in humans: a systematic review and meta-analysis

Epidemiological or in vitro evidence suggests a potential role for flavonoids as anti-inflammatory agents; we investigated the effect of flavonoids-rich foods or supplements on tumor necrosis factor- alpha (TNF-α) and interleukin-6 (IL-6) in long-term placebo-controlled human intervention trials. From 110 human intervention studies selected (MEDLINE, EMBASE, CHORANE, and FSTA databases), 32 long-term placebo-controlled trials were suitable for meta-analysis. After sensitivity analysis, seven studies imputed of bias were excluded and 25 studies were analyzed (TNF-α, n = 2404; IL-6, n = 2174). Levels of TNF-α decreased after flavonoid consumption in the fixed model only (mean difference (MD) (95% CI): -0.098 (-0.188, -0.009), p = 0.032), but metaregression results showed that neither higher dose, nor a longer duration of intervention were associated with a greater effect size. Subgroup analysis did not reveal any significant effect for quercetin and soy, but other sources (red wine, pomegranate, and tea extracts) showed a significant effect size both in fixed (MD (95% CI): TNF-α -0.449 (-0.619, -0.280), p < 0.001; IL-6 -0.346 (-0.612, -0.079), p = 0.011) and random (MD (95% CI): TNF-α -0.783 (-1.476, -0.090), p = 0.027; IL-6, -0.556 (-1.062, -0.050), p = 0.031) effect models. High-quality placebo-controlled trials are needed in order to identify flavonoids as the active ingredients.