Effect of dietary restriction on DNA repair and DNA damage.

Dietary restriction is the only experimental manipulation known to extend lifespan and retard aging in mammals. Therefore, it is a powerful tool for identifying cellular processes that are involved in aging and senescence. Recently, several laboratories have begun to examine the effects of dietary restriction on the integrity of the genome and the ability of cells to repair DNA. In most studies, it was found that the repair of DNA damage, as measured by unscheduled DNA synthesis, was significantly higher in cells isolated from rodents fed calorie-restricted diets compared to cells isolated from rodents fed ad libitum. Dietary restriction also was observed to be associated with a reduction of the levels of certain types of DNA damage; however, preliminary experiments suggest that the effect of dietary restriction on the age-related accumulation of DNA damage depends on the type of DNA damage studied.