The influence of beer with different antioxidant potential on plasma lipids, plasma antioxidant capacity, and bile excretion of rats fed cholesterol-containing and cholesterol-free diets
The aim of this investigation was to assess the influence of beers with different antioxidant potentials on plasma lipid metabolism, plasma antioxidant capacity, and bile excretion of rats fed cholesterol-containing and cholesterol-free diets. Four types of beers were investigated in vitro. Two of them (designated as BeerHigh and BeerLow) with the highest and lowest antioxidant potentials (34.5% and 21.4% and 2.07 mmol/L and 1.65 mmol/L according to beta-carotene assay and Trolox equivalent antioxidant coefficient, respectively), were chosen for the experiment on rats. A total of 60 male Wistar rats were divided into 6 dietary groups of 10 rats each; the groups were designated as Control, BeerA, BeerB, Chol, Chol/BeerA, and Chol/BeerB. The rats in the Control group were fed a basal diet (BD) only, which included wheat starch, casein, soybean oil, vitamin, and mineral mixtures. To the BD of the other five groups were added the following: BeerHigh (BeerA), BeerLow (BeerB), 1% of cholesterol (Chol), 1% of cholesterol and BeerHigh (Chol/BeerA), and 1% of cholesterol and Beer-Low (Chol/BeerB). After 4 weeks of feeding, diets supplemented with BeerHigh and, to a lesser degree, with BeerLow (Chol/BeerA and Chol/BeerB groups) hindered a rise in plasma lipids and a decrease in plasma antioxidant capacity, and increased the bile excretion indices. Supplementation with BeerHigh and, to a lesser degree, with BeerLow in rats fed cholesterol-free diets increased their plasma antioxidant capacity. No significant changes in the plasma lipid levels, antioxidant capacity, and bile excretion indices were observed in the Control group. In conclusion, beer was found to have a positively effect on plasma lipid profile and plasma antioxidant capacity, and to increase the bile excretion indices in rats fed cholesterol-containing diets. The degree of this positive influence is directly connected to the contents of the bioactive components and the related antioxidant potential of beer. It is suggested that to achieve the best results, beer with the highest antioxidant potential must be consumed. (C) 2004 Elsevier Inc. All rights reserved.