Authors
Lipman RD. Smith DE. Blumberg JB. Bronson RT.
Institution
Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University,
Boston, Massachusetts 02111, USA.
Title
Effects of caloric
restriction or augmentation in adult rats: longevity and
lesion biomarkers of aging.
Source
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.