Bioavailability and antioxidant activity of some food supplements in men and women using th D-roms test as a marker for oxidative stress

Most antioxidants show contradictory behaviorsbecause in the biological environment, for unpredictablereasons, they can become prooxidants. Recently,a new simple method to monitor oxidative stressin serum was developed. This test detects the derivatives ofreactive oxygen metabolites (D-Roms). Hydroperoxides areconverted into radicals that oxidize N,N-diethyl-para-phenylendiamineand that can be detected through spectrophotometricprocedures as U.CARR. (Carratelli units). OneU.CARR. corresponds to 0.8 mg/L hydrogen peroxide. Innormal subjects U.CARR. values range from 250 to 300.Values outside this range indicate a modification of theprooxidant/antioxidant ratio. On the basis of this method,we tested three different formulas of antioxidants (F1, F2,F3) in 14 apparently healthy volunteers (11 men and 3 women).Formula 1 was composed of 5 mg zinc, 48 g selenium,400 g vitamin A (as retinol acetate), 50 g -carotene, 15mg vitamin E (as dl--tocopheryl acetate) and 10 mg Lcysteine.Formula 2 was composed of 30 mg bioflavonoidsfrom citrus, 30 mg vitamin C (as L-ascorbic acid), 10 mgcoenzyme Q10 and 1 mg vitamin B-6 (as pyridoxine hydrochloride).Formula 3 was composed of Formula 1 plus Formula2. Each formula was prepared in dry capsules (formulationD1, D2, D3) or in a fluid form (formulation P1, P2, P3).Each formulation was administered for 1 wk in a crossoverdesign. A 15% deviation of U.CARR. levels was chosen asthe cut-off value for a significant change in oxidative stress.Formulas F1 and F3 reduced mean U.CARR. levels in mostof the treated subjects (t test, P < 0.05), whereas F2 wasnot active. Fluid formulations were more active than dryformulations (2 test, P < 0.05). In some cases, a slightincrease in oxidative stress was detected. These minimalincreases were not related to any particular antioxidantformula. In one subject only, the administration of the dryformulation (D1), increased oxidative stress to a level thatreached the cut-off value. In conclusion, when antioxidantsare taken in combination at low dosages they reduce oxidativestress, and little relevant prooxidant activity is detectable.