null effect of caloric restriction in aged rats

Doug Skrecky (
Fri, 20 Aug 1999 08:46:10 -0700 (PDT)

Lipman RD. Smith DE. Blumberg JB. Bronson RT. Institution
Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts 02111, USA.
Effects of caloric
restriction or augmentation in adult rats: longevity and lesion biomarkers of aging.
Aging (Milano). 10(6):463-70, 1998 Dec. Abstract
Caloric restriction (CR) initiated in young rodents has been thoroughly documented to enhance longevity, but its efficacy when introduced at older ages has not been well investigated. Cohorts of 18- and 26-month-old male F344 x BN F1 hybrid rats were fed either: 1) NIH-31 meal (C); 2) vitamin and mineral fortified NIH-31 meal (R); or 3) vitamin and mineral fortified NIH-31 meal supplemented with corn oil and sweetened condensed milk (S). The C control rats were fed ad libitum, R rats were restricted to 32% of the caloric intake of the controls, and S rats were allowed to consume not more than 8% more calories than C rats. After 6 weeks, the average weights were significantly different between all diet and age groups. Although calorie manipulation altered body weight, no significant effect of the dietary intervention on longevity was found. The average lesion burden, including tumor burden and prevalence of nearly all commonly occurring lesions, were comparable between the groups. Thus, the manipulation of weight at ages beyond middle age has a much less profound impact than similar interventions during growth and maturation in rats.

Additional note by poster:

This may have some relevance for humans as well. The scientific evidence does not support any significant direct effect of caloric intake on mortality of healthy adult humans.