Determination of serum antioxidants following a diet rich in antioxidants

OBJECTIVE Since free radicals can cause damage to lipids, proteins and DNA, they are thought to be involved in the pathogenesis of various diseases. Cancer, Alzheimer's disease, arthritis, atherosclerosis and heart disease are associated with oxidative damage. High concentrations of antioxidants in the blood appear to increase the defence of the organism against certain diseases, and treatment with antioxidants is often proposed as part of the therapeutic regime. Dietary ingredients such as vitamins play an important role in the effort of the organism to counteract free radicals, although research findings are sometimes contradictory. Administration of synthetic antioxidants as a dietary supplement does not appear to have the same beneficial effect as consumption of the same antioxidants as food ingredients. The kind of antioxidants in food and the food preparation procedure and food mixtures used, also influence their effectiveness. METHOD.he level of the total antioxidant capacity (TAC) was measured in the serum of 40 male and female healthy volunteers before (1st blood sample) and after (2nd blood sample) they had followed a special diet rich in antioxidants for 30 days. Detailed records were maintained before the study and during the 30 day period of the special diet, which was rich mainly in vitamins C and E, lycopene and flavonoids. After the 30 day period and the 2nd blood sampling, the volunteers were allowed to follow a free diet for 15 days, after which a 3rd blood sample was taken. Antioxidant activity was estimated by the influence of 10 mu L of serum on the oxidation of 2.2'-azinobis(3-ethylbenthiazoline)-6-sulfonic acid (ABTS) by the ferryl myoglobin-H2O2 system. Trolox, the water soluble analogue of vitamin E, was used as control. The TAC was expressed as trolox equivalents. RESULTS-CONCLUSIONS An average 62% (p=0.000) increase in total antioxidant capacity was observed after the 30 day period of antioxidant rich diet, and this increase was maintained after the following 15 days of free diet (54.0%, p=0.000). Those people who did not follow the diet showed no significant differences in their serum TAC levels throughout the study.