SHORT-TERM MODERATE ENERGY RESTRICTION DOES NOT AFFECT INDICATORS OF OXIDATIVE STRESS AND GENOTOXICITY IN HUMANS

Restriction of energy intake (ER), without malnutrition of essential n utrients, has repeatedly been demonstrated to increase longevity in ro dents, In the antioxidant theory of aging the lack of balance between the generation of free radicals and free radical scavenging was though t to be a main causal agent in the aging process. From this point of v iew the antiaging effect induced by ER might be due to the lower rate of free-radical production and related damage induced by a lower metab olic rate, The antiaging effects of ER might also occur in humans. Thi s study explored the effects of a 10-week moderately energy-restricted diet (80% of habitual) in 24 non-obese middle-aged men (16 ER subject s, 8 controls) on resting metabolic rate (RMR) and indicators of the p rimary antioxidant defense system, oxidative stress and genotoxicity, RMR decreased significantly in both groups, even when adjustments were made for the change in body composition. The increase in blood vitami n C concentrations correlated with the increase in urinary 8-hydroxyde oxyguanosine (80HdG) excretion, The change in urinary 80HdG excretion also correlated with the change in RMR per kg fat-free mass. No differ ences between groups were found for changes in indicators of genotoxic ity, erythrocyte catalase, glutathione peroxidase and superoxide dismu tase activity and in plasma vitamin E, A or beta-carotene concentratio ns. We conclude that 10 weeks of moderate ER did not affect indicators of antioxidative capacity, oxidative stress and genotoxicity of human s, Since subjects were not in energy balance at the end of the study, no conclusions can be made with respect to long-term effects.