Effect of dietary restriction on serum antioxidant capacity in rats

The effects of dietary restriction on serum antioxidant capacities were studied in male Fischer 344 rats. Dietary restriction was started at the age of 6 weeks and consisted of 60% of the mean daily food intake of the ad libitum fed controls. They were killed at 7 and 18 months of age. The antioxidant capacities of whole serum and the non-protein fraction of serum were assessed using the oxygen radical absorbance capacity (ORAC) assay with a peroxyl radical generator. Rats that consumed a diet restricted by 40% in calories had significantly lower ORAC activities in whole serum and the non-protein fraction of serum. The decreased serum ORAC activity is seemingly an organism's physiologically appropriate response to reduced oxidative stress through a down-regulation mechanism.