We assessed the impact of oligofructose (OFS) and dextrin (DEX) as diet supplements on hepatic redox state. Rats were fed either a 10% OFS or a 10% DEX supplemented diet for 9 wk. In the DEX diet group, the levels of hepatic protein carbonylation were decreased by 63%. Total glutathione and reduced glutathione (GSH) contents were reduced in the OFS and DEX diet groups by around 20%. DEX supplementation significantly reduced oxidized glutathione (GSSG) levels resulting in a 33% increase in the GSH/GSSG ratio. The activity of the hepatic antioxidant enzymes was not changed by either OFS or DEX supplementation. OFS supplementation caused a decrease in serum levels of triglycerides (36%), cholesterol (24%), HDL (16%) and LDL (17%). DEX supplementation only reduced triglycerides (32%) and urea (22%). Both diets increased serum levels of acetate by fivefold and propionate by twofold, but DEX diet decreased butyrate levels by 75%. Due to their different composition/structure these two dietary fibers affected metabolism in different ways. Diet supplementation with 10% DEX can potentially improve host health, by protecting the liver from protein carbonylation and by improving GSH/GSSG ratio and diet supplementation with 10% OFS can improve the lipid profile.