Effects of Uncooked Powdered Food on Antioxidative System and Serum Mineral Concentrations in Rats Fed Unbalanced Diet

Lee, Yeo Jin; Lee, Hae Mi; Park, Tae Sun

Abstract

Antioxidative function of uncooked powdered food (Sangsik) was evaluated in rats consuming nutritionally unbalanced diet including 1% cholesterol, high proportion of animal lipids (lard : soybean oil : 8 . 2) , sub-optimal levels of vitamin and mineral mixture along with 0.5% ethanol in drinking water. The uncooked powdered food tested in the present study was a mixture composed of 42 kinds of plant foods (cereals, legumes, seaweeds, vegetables, and fruits) supplemented with vitamins and minerals, and dietary fiber. Control rats were fed the semi-purified diet based on the AIN-93G composition, and nutritionally unbalanced rats were divided into 3 groups, and fed one of the following diets with 0.5% ethanol in drinking water for 5 weeks : unbalanced control diet (UC) ,20% Sangsik powder supplemented diet (S20), and 40% Sangsik powder supplemented diet (S40) . Food efficiency ratio was significantly higher in rats fed S40 compared to the value for rats fed UC (p<0.05). Hepatic level of thiobarbituric acid reactive substances (TBARS) was significantly lower in rats fed UC compared to that for control rats (p<0.05), and was not influenced by dietary supplementation of the Sangsik powder. Hepatic superoxide dismutase (SOD) activity was significantly higher in rats fed UC compared to that for control rats (p<0.05), and significantly reduced in rats fed S20 or S40 compared to the value for unbalanced control rats. Feeding unbalanced control diet significantly reduced the ratio of hepatic GSH-Px + catalase/SOD activities compared to the value for control rats, and this decrease in the ratio of antioxidant enzyme activities was reversed by adding the Sangsik powder to the diet at 20% (p<0.05) . Based on the results of antioxidant enzyme activities, feeding uncooked powdered diet appears to provide a favorable environment for body's antioxidative defense mechanism. Serum levels of Fe and Cu were significantly lower in rats fed the Sangsik powder supplemented diets compared to the value for unbalanced control rats (p<0.05), and levels of Se, Mn, and Zn were also tended to be decreased by dietary supplementation of the Sangsik powder. These results postulate the possibility that ingredients used in the uncooked powdered food may decrease the bioavailability of trace elements in rats.