Biomarkers Part II: Biomarkers to Estimate Bioefficacy of Dietary/Supplemental Antioxidants in Sport

Exercise and oxidative stress: Potential effects of antioxidant dietary strategies in sports

“…We have recently shown how levels of oxidative stress, appears reduced after an Ironman race [18]. These results are not surprising, if seen in view of the so-called "hormesis" theory, and may also explain the epidemiological data showing that elite athletes have a longer life expectancy than the general population, as well as the finding of an inverse linear dose-response relationship between volume of physical training and all-cause mortality [2,19,20].…”

“…The measurement of the oxidative stress in vivo is difficult for the extreme complexity of the antioxidant/oxidant network and the very short half-life of free radicals [2]. Generally indirect M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 5 biomarkers are measured, as conjugated dienes, hydroperoxides, malondialdehyde, 4-hydroxynonenal, hydrocarbons such as pentane and ethane (in breath), F2-isoprostanes and oxLDL [1,2].…”

“…Generally indirect M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 5 biomarkers are measured, as conjugated dienes, hydroperoxides, malondialdehyde, 4-hydroxynonenal, hydrocarbons such as pentane and ethane (in breath), F2-isoprostanes and oxLDL [1,2]. Conversely, total antioxidant capacity can be estimated in biological fluids and tissues as a whole, or in its components, including enzymatic (such as catalase, glutathione peroxidase, superoxide dismutase) and non-enzymatic antioxidants (such as vitamins E, A, C, and glutathione and uric acid) [1,2]. Currently, no shared consensus exists on which biomarkers or group of biomarkers must be used to estimate exercise effects as well as bioefficacy of dietary/supplemental antioxidants in sports.…”

“…Data comparison is still extremely complex for many reasons. They may vary according to presence of different physiological and pathological determinants, including genetic profile, age, sex, lifestyle habit, use of pharmacological treatments or concomitant diseases [2].…”

“…Nonetheless, while exercise leads to increased oxidative stress, this same exercise stimulus appears necessary to allow for an upregulation in endogenous antioxidant defenses according to the hormesis theory ( Figure 1). Specifically this hypothesis suggests the organism response to repeated increases in ROS production via exercise bouts by through an adaptive reaction which includes the up-regulation of antioxidants and the shift towards a more reducing environment, induction of increased stress resistance and ultimately leading to an increased lifespan [2]. Conversely, in the prevention of oxidative stress for performance enhancement, aging prevention, pathological risk in professional athletes a number of factors may be taken into account, including adaptation mechanisms (hormesis) as well as detoxifying function of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase) versus non-enzymatic antioxidants (such as vitamins E, A, C, and glutathione and uric acid) [2].…”