Partial resistance of low density lipoprotein to oxidation in vivo after increased intake of berries

Background acid Aim: The health-promoting effects of fruit-and vegetable-ba sed diets are known to be associated with their antioxidative components. W e found in our preliminary in vitro laboratory tests that extracts of many common Finnish edible berries are potent scavengers of peroxyl radicals and inhibitors of lipid peroxidation. We therefore designed the current study to evaluate both the long-term (8 weeks) and short-term (5 hours) effects o f increased intake of three berries on antioxidant potential and lipid pero xidation. Methods and Results: Healthy 60-year-old men were randomized to berry, supp lement and control groups (20 men in each group). The berry group ate, in a ddition to their normal diet, a 100 g portion of deep-frozen berries (bilbe rries, lingonberries, or blackcurrants) daily for 8 weeks. The other groups ingested daily 100 mg of alpha -tocopherol and 500 mg of ascorbic acid (su pplement group) or 500 mg of calcium gluconate (control group). In the shor t-term experiment 6 men ate 80 g of each of the three berries in one go. Se rum ascorbate concentrations increased significantly in both the berry and the supplement group. Serum alpha -tocopherol levels and the antioxidant po tential (TRAP) in low density lipoprotein (LDL) increased in the supplement group only. In the berry group, slightly lowered LDL diene conjugation (p= 0.074) and slightly increased total serum TRAP (p= 0.084) values were obser ved. No changes were found in these measures in the supplement or the contr ol group. In the short-term experiment, LDL TRAP showed a small increase(ab out 10%, p=0.039) during five hours after the intake of 240 g berries. Conclusions: The effects of consumption of berries on antioxidant potential and diene conjugation in LDL particles in vivo appear to be small. (C) 200 0, Medikal Press.