Retardation of cognitive aging by life-long diet restriction: implications for genetic variance.

Long-term moderate dietary restriction (DR) has been reported to extend life spans, delay the onset and decrease the incidence of a broad spectrum of age-associated diseases; however, its effect on cognition is still unclear. Our previous results indicated that long-term DR failed to retard cognitive and psychomotor aging in the inbred strain, Fischer-344 rats. In the present experiment, an anti-aging effect of DR on various types of cognitive and sensorimotor behaviors was found in F1 hybrid Fischer-344 x Brown Norway (F-344xBN) rats, while no effect of DR was detected in the second parental inbred strain, Brown-Norway (BN) rats. These findings show that the lack of an effect of DR on cognitive aging, which was previously found in Fischer-344 rats, is not a universal phenomenon. Instead, the effect of DR may depend upon the genetic makeup of the animals. Thus, a more diverse genetic milieu, such as in hybrid rats, relative to inbred rats, may increase the susceptibility to an effect of DR on age-related cognitive decline.