Efficiency of apples, strawberries, and tomatoes for reduction of oxidative stress in pigs as a model for humans

Objective The present study investigated the potency of apples, strawberries, and tomatoes in decreasing oxidative stress in pigs as a model for humans. Methods Forty-eight growing pigs were individually penned in metabolic cages and divided into six groups. All groups received isocaloric daily rations composed of a basal diet supplemented with starch, linseed oil, linseed oil and apples, linseed oil and strawberries, linseed oil and tomatoes, or linseed oil, apples, strawberries and tomatoes. Oxidative stress was evaluated at the beginning and at the end of the 22-d experimental period by measuring the degree of DNA damage in mononuclear blood cells, the concentration of malondialdehyde (MDA) in plasma, the MDA excretion rate, the concentration of tocopherols in plasma, plasma total antioxidant status, and erythrocyte glutathione peroxidase concentration. Results The results confirmed that the linseed oil diet significantly increased MDA formation in the body and DNA damage to mononuclear blood cells in comparison with the starch diet. Although the MDA concentration in plasma was significantly decreased in all fruit groups, urine MDA excretion rate was decreased only in the linseed oil/apple and linseed oil/apple/strawberry/tomato groups. Supplementation with fruit significantly decreased DNA damage, was more pronounced in the linseed oil/apple and linseed oil/apple/strawberry/tomato groups. Significantly lower glutathione peroxidase concentrations were observed only in the linseed oil/strawberry group. Conclusions Our findings support the hypothesis that supplementation with apples, strawberries, or tomatoes effectively decreases oxidative stress by decreasing MDA formation in the body and by protecting mononuclear blood cells against increased DNA damage. This effect was particularly pronounced in the group supplemented with a fruit mixture; among the single fruit supplements, the most beneficial effect was obtained with apples.