Oxidative stress, muscle damage and inflammtion in kayakers and canoeists: effects of acute and chronic exercise and antioxidants supplementation

Tese de doutoramento em Nutrição Humana apresentada à Faculdade de Ciências da Nutrição e Alimentação da Universidade do PortoResumo da tese:Presume‐se que o exercício possa elevar a geração de espécies reactivas de oxigénio a um nível que ultrapasse a fortalecida defesa antioxidante dos atletas, causando danos oxidativos irreparáveis a nível celular, com prejuízo da sua saúde e performance física. Este trabalho teve como objectivo descrever o estado antioxidante, o stress e dano oxidativos de um grupo de caiaquistas e canoístas em repouso e em resposta ao exercício agudo (prova de caiaque de 1000 m) e ao exercício crónico (1 ano de treino e competição), bem como investigar se a sumplementação com uma combinação de antioxidantes poderia atenuar estes efeitos. Estimou‐se a ingestão alimentar de antioxidantes e determinou‐se a actividade da dismutase do superóxido (SOD), reductase da glutationa (Gr), peroxidase da glutationa e cínase da creatina e os níveis do estado antioxidante total (TAS), ácido úrico, α‐tocoferol, retinol, α‐caroteno, β‐caroteno, licopeno, luteína e zeaxantina, substâncias reactivas ao ácido tiobarbitúrico (TBARS), interleucina‐6 (IL‐6) e cortisol em várias ocasiões em 2 épocas deportivas, quando os atletas se encontravam no Centro de Treinos Nacional. As amostras de sangue foram colhidas em repouso e 15 minutos depois do conclusão da prova de 1000m de caiaque, antes e após do período de suplementação. Neste último estudo, os atletas foram distribuídos aleatoriamente para receber um placebo ou um suplemento antioxidante (272 mg α‐tocoferol, 400 mg vitamina C, 30 mg β‐caroteno, 2 mg luteína, 400 μg selénio, 30 mg zinco and 600 mg magnésio) durante 4 semanas. (...)Thesis abstract:It is postulated that exercise generates a surplus production of reactive oxygen species that may even surpass the strengthened antioxidant defences of athletes, causing irreparable cellular oxidative damage, which can harm their health and physical performance. This work aimed to describe antioxidant status, oxidative stress and damage of a group of elite kayakers and canoeists at rest and in response to acute exercise (1000m kayak trial) and chronic exercise (1 year of habitual training and competition), and investigate if a supplementation with a combination of antioxidants could attenuate these effects. Dietary intake of antioxidants was estimated, and blood superoxide dismutase (SOD), glutathione reductase (Gr), glutathione peroxidase (GPx) and creatine kinase (CK) activities, and total antioxidant status (TAS), uric acid, α‐tocopherol, retinol, α‐carotene, β‐carotene, lycopene, lutein plus zeaxanthin, thiobarbituric acid reactive substances (TBARS), interleukin‐6 (IL‐6) and cortisol levels were determined in several occasions in 2 seasons, while athletes were training on the Portuguese National Team Campus. The blood samples were collected in resting conditions and 15 min after a 1000m kayak race, both before and after supplementation. In last study, athletes were randomly assigned to receive a placebo or an antioxidant supplement (272 mg α‐tocopherol, 400 mg vitamin C, 30 mg β‐carotene, 2 mg lutein, 400 μg selenium, 30 mg zinc and 600 mg magnesium) for 4 weeks. Kayakers/canoeists exhibited significantly elevated markers of lipid peroxidation (TBARS) and muscle damage (CK) compared with sedentary subjects, despite having increased α‐ tocopherol, α‐carotene and β‐carotene levels and SOD activity. The activities of GPx and Gr, and the levels of lycopene, lutein + zeaxanthin, retinol and uric acid were similar between groups. (...

The Role of High-fat Feeding on the Up-regulation in Antioxidant Enzymes: A Potential

While RONS are produced as part of normal metabolism, excess production can occur in response to stressors, such as physical exercise and ingestion of excess nutrients (e.g., saturated fat). Over time this may lead to an up-regulation in antioxidant enzyme activity, in an attempt to protect cells. The purpose of this investigation was to determine if an increase in antioxidant enzyme activity is observed following repeatedingestion of high fat meals. Sixteen healthy men consumed10 high fat milkshakes over a 3+ weekperiod. Blood was taken from subjects on the firstday of each week (before andfor 4 hours after milkshake ingestion) and analyzed for oxidative stress biomarkers. Repeated high-fat feeding didnot result in anyup-regulation in antioxidant enzymatic activity or attenuation in oxidative stress. Thesedata indicate that the RONS production associated with repeated consumption of high-fat meals does not induce an adaptive response within the blood antioxidant defense system

Uric acid enhances longevity and endurance and protects the brain against ischemia

Among mammals, there is a positive correlation between serum uric acid (UA) levels and life span. Humans have high levels of UA because they lack a functional urate oxidase (UOX) enzyme that is present in shorter lived mammals. Here, we show that male and female mice with UOX haploinsufficiency exhibit an age-related elevation of UA levels, and that the life span of female but not male UOX+/− mice is significantly increased compared to wild-type mice. Serum UA levels are elevated in response to treadmill exercise in UOX+/− mice, but not wild-type mice, and the endurance of the UOX+/− mice is significantly greater than wild-type mice. UOX+/− mice exhibit elevated levels of brain-derived neurotrophic factor, reduced brain damage and improved functional outcome in a model of focal ischemic stroke. Levels of oxidative protein nitration and lipid peroxidation are reduced in muscle and brain tissues of UOX+/− mice under conditions of metabolic and oxidative stress (running in the case of muscle and ischemia in the case of the brain), consistent with prior evidence that UA can scavenge peroxynitrite and hydroxyl radical. Our findings reveal roles for UA in life span determination, endurance and adaptive responses to brain injury, and suggest novel approaches for protecting cells against injury and for optimizing physical performance.España, Ministerio de Educación, Cultura y Deporte EX2009–091

The effect of VC on immunoendocrine and oxidative stress responses to exercise

The depression of the immune system function that is typically observed after strenuous exercise is believed to be possibly mediated by stress hormones, cytokines and oxidative stress. The aim of this study was to measure immunoendocrine and oxidative stress responses after the ingestion of two different doses of Vitamin C (VC) supplementation. Twenty-four healthy untrained males participated in a 30-min exercise at 75%Vo2max. Immediately pre-exercise, the participants received either of the following regimens: placebo, 500 mg and 1000 mg of VC. Blood samples were obtained prior to ingestion, immediately after ingestion, 2hrs after ingestion and also 2hrs and 24hrs after exercise. Vitamin C used in doses of 500 mg and 1000 mg could significantly increase the plasma VC concentration and antioxidant capacity in both vitamin receiving groups. The increase in total antioxidant capacity (TAC) followed a significant decrease in post-exercise oxidative stress markers like malondialdehyde (MDA) (P<0.05). Markers of inflammation (total leukocytes, neutrophils and IL-6), muscle damage, creatine kinase (CK) and stress hormone (cortisol) were found to significantly increase in response to the exercise (P<0.05), but VC supplementation failed to decrease these factors significantly. The results suggest that acute supplementation with moderate and high doses of VC might prevent exercise-induced lipid peroxidation but not inflammatory markers

Quercetin in Sports and Exercise: A review

International Journal of Exercise Science 16(2): 1334-1384, 2023. This paper systematically reviews the latest evidence regarding Quercetin’s (Q) effect following exercise performance, aerobic and anaerobic exercise, muscle-damaging bouts and highlights blood biomarkers associated with muscle damage and recovery. Google Scholar, Web of Science, and MedLine (PubMed) searches were conducted through July- December 2021. Peer-reviewed studies that investigated Q as a single ingredient or in combination with other ingredients at dosages of 500 mg - 3000 mg, ranging from 15 min-to-1 h prior to exercise bout or chronic dose (7 days - 8 weeks) of consumption were included. A total of 34 studies met the inclusion criteria for the review. Key results include significant performance improvements in the following: VO2max (n = 2), time to exhaustion (n = 4 articles), fatigue decrement (n = 1 article), muscle damage (n = 3 articles), strength, torque velocity, and neuromuscular performance (n = 3 articles), redox potential (n = 1 article), repeated sprint performance and oxygen extraction (n = 1). Q also caused a change in systemic biomarkers: decrease in creatine kinase (n = 2), c-reactive protein (n = 4), lactate dehydrogenase (n = 4), inflammatory markers (n = 3), lipid peroxidation (n = 3) in aerobic and anaerobic performance. Varied findings exist regarding the efficacy of Q supplementation on exercise performance and recovery outcomes. The source of Q, training status of subjects, and exercise protocol performed may contribute to the effectiveness of Q as an antioxidant, anti-inflammatory, or ergogenic agent in exercise

Oxidative Stress Response to Short Duration Bout of Submaximal Aerobic Exercise in Healthy Young Adults

The purpose of this study was to investigate the oxidative stress response to a short duration bout of submaximal exercise in a cohort of healthy young adults. 15 apparently healthy college age males and females completed a modified Bruce-protocol treadmill test to 75–80% of their heart rate reserve. Blood samples collected immediately before (pre-exercise), immediately after, 30, 60 and 120 minutes post-exercise were assayed for total antioxidant capacity (TAC), superoxide disumutase (SOD), thiobarbituric acid-reactive substances (TBARS), and protein carbonyls (PC). SOD activity was significantly increased from pre-exercise levels at 30 minutes (77%), 60 minutes (33%), and 120 minutes (37%) post-exercise. TAC levels were also significantly increased from pre-exercise levels at 60 minutes (30%) and 120 minutes (33%) post-exercise. There were no significant changes in biomarkers for reactive oxygen/nitrogen species (RONS) mediated damage (TBARS and PC) across all post-exercise time points. In a cohort of healthy young adults, a short duration bout of submaximal aerobic exercise elicited increases in antioxidant activity/concentration, but did not evoke changes in oxidative stress-induced damage. These results may suggest that: (1) short duration bouts of submaximal aerobic exercise are sufficient to induce RONS generation; and (2) the antioxidant defense system is capable of protecting against enhanced RONS production induced by a short duration, submaximal exercise bout in healthy young adults

Fish Oil Supplementation Reduces Markers of Oxidative Stress But Not Muscle Soreness After Eccentric Exercise

Peer reviewedPostprin

The effects of fruit vegetable concentrate upon oxidative stress and buffering capacity in vivo

Western diets are high in protein and insufficient in fruit and vegetable consumption. This can result in low-grade acidosis, which is linked with various metabolic diseases and can also impact exercise performance. Supplementing with fruit vegetable concentrate (FVC) could potentially attenuate the effects of low-grade acidosis and provide protection against the effects of oxidative stress due to the high antioxidant potential within these nutritional supplements.The first study investigated the dose response of acute FVC supplementation upon blood acid-base levels during resting conditions. Eight physically active males (age: 23 ± 2 yr; height 180.1 ± 6.2 cm; weight 76.9 ± 7.2 Kg) consumed either a manufacturer recommended dose (9 g) of energised greens (FVC), an equal dose placebo (PLC), or a known acid-base regulator (NaHCO₃) in a single blind, randomised crossover design. Capillary blood samples were taken every 15 minutes to measure changes in blood pH, bicarbonate (HCO₃-) and base-excess (BE). A visual analogue scale (VAS) was used to analyse potential changes in gastrointestinal discomfort. Blood pH rose in all trials but was only significantly elevated in the NaHCO3 trial (P0.05). BE significantly increased during the NaHCO₃ trial (P0.05) however, were significantly different between pre-ingestion and post-exercise concentrations (P<0.05).The results from the current thesis show that acute FVC supplementation does not have an effect upon blood acid base levels at rest and therefore it is unlikely to attenuate changes in acid-base balance as a result of exercise. Furthermore, despite containing a high abundance of antioxidant compounds, acute supplementation with FVC does not attenuate the effects of exercise induced oxidative stress in healthy males during intermittent exercise. Further research is required as to the effects of acute and chronic supplementation upon acid-base regulation and antioxidant capacity as a result of FVC supplementation, as well as the effects of such supplementation upon populations with poor diets that lack fruit and vegetables

Effects of a Rubus coreanus Miquel supplement on plasma antioxidant capacity in healthy Korean men

Korean raspberry, Rubus coreanus Miquel (RCM), contains high concentrations of phenolic compounds, which prevent oxidative stress. To determine the effect of RCM on antioxidant capacity in humans, we assessed in vivo lipid oxidation and antioxidant enzyme activities from plasma in 15 healthy men. The subjects ingested 30 g of freeze-dried RCM daily for 4 weeks. Blood was taken at baseline and at the end of the study to determine blood lipid profiles, fasting plasma glucose, liver function, lipid peroxidation, and antioxidant enzyme activities. RCM supplementation had no effect on blood lipid or fasting plasma glucose concentrations but decreased alkaline phosphatase activity. RCM supplementation increased glutathione peroxidase activities (P < 0.05) but had no effect on lipid peroxidation. These results suggest that short-term RCM supplementation may offer health benefits by enhancing antioxidant capacity in a healthy population

The effect of beta-carotene vitamin E, and vitamin C supplementation upon work capacity during a protocol of arm curl exercise using the Biodex dyanamometer

The effect of acute and chronic supplementation upon work capacity in trained and untrained subjects was examined using 10 normal healthy subjects (ages 19-23). The subjects were tested using a double-blind crossover design. During the two supplemental stages subjects ingested either the placebo or antioxidant mixture capsules (beta-carotene, vitamin C, vitamin E). There was a 28 day washout period between the two supplemental stages. Subjects were tested during each stage for an acute effect (one day of supplementation) and chronic effect (twenty-eight days of supplementation). Testing consisted of seven sets of arm curl exercises with a 60-second rest period between each set. Work, during the last three sets of each phase, was recorded and compared for each subject. Hypotheses tested was whether an acute (one day) and chronic (28 days) supplementation protocol would have an effect upon work capacity in untrained as compared to trained subjects. No significant differences were seen after acute or chronic supplementation in either trained or untrained subjects. However, power for the study was too low to make a determination without a high risk of Type II error. Significant subject dropout and work measure variability contributed to the low power