Dietary antioxidants and exercise.

Department of Exercise and Sport Sciences, Center for Exercise Science, University of Florida, Gainesville, FL 32611, USA.
Journal of Sports Sciences (Impact Factor: 2.1). 02/2004; 22(1):81-94. DOI: 10.1080/0264041031000140563
Source: PubMed

ABSTRACT Muscular exercise promotes the production of radicals and other reactive oxygen species in the working muscle. Growing evidence indicates that reactive oxygen species are responsible for exercise-induced protein oxidation and contribute to muscle fatigue. To protect against exercise-induced oxidative injury, muscle cells contain complex endogenous cellular defence mechanisms (enzymatic and non-enzymatic antioxidants) to eliminate reactive oxygen species. Furthermore, exogenous dietary antioxidants interact with endogenous antioxidants to form a cooperative network of cellular antioxidants. Knowledge that exercise-induced oxidant formation can contribute to muscle fatigue has resulted in numerous investigations examining the effects of antioxidant supplementation on human exercise performance. To date, there is limited evidence that dietary supplementation with antioxidants will improve human performance. Furthermore, it is currently unclear whether regular vigorous exercise increases the need for dietary intake of antioxidants. Clearly, additional research that analyses the antioxidant requirements of individual athletes is needed.

1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Overproduction of reactive oxygen and nitrogen species during physical exercise, exercise induced oxidative stress and antioxidant supplementation is interesting and controversial concepts that have been considered during the past decades. In this review, we aimed to summarize current evidence in relation to antioxidant supplementation outcomes during exercise and physical activity. For this aim, we obtained relevant articles through searches of the Medline and PubMed databases between 1980 to 2013. Although major studies have indicated that antioxidants could attenuate biomarkers of exercise-induced oxidative stress and the use of antioxidant supplement is a common phenomenon among athletes and physically active people, there are some doubts regarding the benefits of these. It seems that the best recommendations regarding antioxidants and exercise are having a balanced diet rich in natural antioxidants and phytochemicals. Regular consumption of various fresh fruits and vegetables, whole grains, legumes and beans, sprouts and seeds is an effective and safe way to meet all antioxidant requirements in physically active persons and athletes.
    03/2015; 6(1):e24898. DOI:10.5812/asjsm.24898
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cardiac cachexia is a syndrome that has received increased attention in recent years. Although an association between proteolysis and cardiac cachexia has been proposed, the direct influence of oxidative stress on the process has not been demonstrated. In the present study, the right (RH) and left (LH) hearts (atrium and ventricle of each side of the heart) were collected from rats at the 5th and 10thdays after phosphate buffer (control) orWalker-256 solid tumour implantation. Immediately after sacrifice, cachexia was determined in tumour-bearing animals by the formula: [(inicial body weight – final body weight + tumor weight + weight gain of control group) / (initial body weight + body mass gain of control group)] x 100%; RH and LH were stored until use. Oxidative stress and proteolysis were determined in each collected sample. In addition, heart samples were collected from a separate set of animals to determine the thickness of the left and right ventricles. Cachexia values increased over time after tumour implantation from 6.85% at the 5thday to17.76% at the 10th day. There was no significant difference in LH wet weight and ventricle thickness compared with the control, where as RH wet weight (0.109 ± 0.09 g at the 5thday and 0.093 ± 0.09 g at the 10th day) and thickness (420 ± 16 μm at the 5thday and 279 ± 08 μm at the 10th day) were significantly decreased at both time points when compared with control values (0.153 ± 0.06 g and 607 ± 21 μm, respectively). tert-Butyl-stimulated chemilumine scence analysis revealed a significant increase in the LH and decrease in the RH oxidative stress profiles. Carbonylated proteins increased in the LH (140%, p < 0.05) and RH (100%, p < 0.05) at the 5thday, and significantly decreased in both sides on the 10th day compared to controls. Chemotrypsin-like, caspase-like, and calpain-like activities were evaluated by chemiluminescence, and only calpain-like activity was found to increase at the 5th day in the RH. In the LH, all proteolytic activities systems were decreased when compared with controls. Together, these results demonstrate that oxidative stress appears to play a different role in mass modulation on the LH and RH. The proteolyticsystems evaluated herein also appear to have different effects on the responses developed during cardiac cachexia in the two sides of the heart.
    Pathophysiology 11/2014; DOI:10.1016/j.pathophys.2014.05.003
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Drug-induced liver injury is a problem of increasing significance, but has been a long-standing concern in the treatment of tuberculosis (TB). The present study evaluates the possible hepatoprotective effects of Quercetin against the experimentally induced hepatotoxicity with isoniazid (INH) and rifampicin (RFP) in rats. Twenty-four rats were allocated into 4 groups (6 rats in each group), and treated as follow: group I, received normal saline orally; group II, received normal saline + (INH 10mg/Kg/day and RFP 10 mg/Kg/day orally); group III, received Quercetin (300mg/kg/day) + (INH and RFP as in group II);group IV, received N-acetyl cysteine (NAC) (50 mg/Kg/day) + (INH and RFP as in group II).After 42 days, the rats were scarified; blood samples obtained for evaluation of total antioxidant status (TAS), CRP, and the activities of ALT, AST, and ALP. Liver tissue sections were prepared for histopathologicalevaluation. The results clearly demonstrate that Quercetin provides significant protection against INH and RFP-induced toxicity in liver of rats, revealed as reduction in AST and ALT activities, increase in total antioxidant capacity, and improvements histopathological picture of the liver. In conclusion, orally administered Quercetin protects the liver against INH and RFP-induced hepatotoxicity in rats.
    07/2014; 2(3):56-60. DOI:10.12691/ajps-2-3-3