The Oxidative Stress Balance Measured in Humans with Different Markers, Following a Single Oral Antioxidants Supplementation or a Diet Poor of Antioxidants

Abstract

Four different markers of oxidative stress [OS] (8-OHdG in urine, 8-Iso-PGF, hydroperoxides and carbonylated proteins in plasma, a new marker of antioxidant capacity (AC) in plasma/urine/saliva, and hs-CRP were determined concomitantly in twelve apparently healthy volunteers. All the markers were determined at 8 am, 10 am, 12 am in three different moments: after a week of normal diet (baseline), after an acute supplementation with an antioxidant pool, and finally following a week of a diet poor in antioxidant. The supplementation of antioxidants determined a significant (t test p < 0.05) decrease up to 12% of 8-OHdG in urine and up to 46% of carbonylated proteins in plasma, whereas hydroperoxides and 8-Iso-PGF were unmodified; the antioxidant capacity increased significantly (t test p < 0.05) up to 19%, 78%, and 67%, respectively in plasma, urine and saliva. Hs-CRP was unchanged.The diet poor in antioxidant caused significant increases (t test p< 0.01) of hydroperoxides (up to 24%), 8-Iso-PGF 23 (up to 69%), carbonylated proteins (up to 76%) and 8-OHdG (up to 16%): hs-CRP increase reached 72% despite the levels were still within the normal range. Any reduction of soluble antioxidants activity in plasma was detected, whereas in urine and saliva a reduction of 45% and 38% respectively was shown. In conclusion, the antioxidant surplus determined by a single antioxidants pool administration seems to protect DNA and proteins from oxidation. On the contrary the shortage of antioxidant intake increases all the markers of OS, particularly those related to lipids and proteins, whereas the DNA seems to be protected more efficiently. The AC in plasma tends to be constant, and the limitation of antioxidants intake is followed by reduction of AC in urine and saliva.