A baby rhesus.
Remember when the starvation diet was the key to extending your life span. It seems like that is up for questioning again:
Decades of research have linked low-calorie diets with extended survival, but a new report finds that rhesus monkeys on strict diets don’t live longer than their counterparts getting a standard diet.
The findings, reported August 29 in Nature, run counter to a 2009 study from the University of Wisconsin–Madison that showed a clear survival advantage in a calorie-restricted group of similar rhesus monkeys. Scientists suspect that differences in the two studies’ designs might explain the discordant findings, leaving the question of longevity still dangling.
The median life span for a rhesus monkey in captivity is about 27 years, but some can reach age 40, says study coauthor Julie Mattison, a physiologist at the aging institute. The NIA study includes 121 monkeys, divided between calorie-restricted and standard-diet groups. Some monkeys were put on one diet or the other when they were already well into middle age. Others started on the regimen earlier in life, some very young.
Now, 23 years into the study, more than half of the monkeys have died and no survival advantage shows up from calorie restriction, the scientists report. The team considered only aging-related deaths attributable to causes such as heart disease, diabetes and cancer.
The calorie-restricted monkeys in the NIA study get about 25 to 30 percent fewer calories per day than normal, Mattison says. But she acknowledges that the control diet might also slightly underfeed the monkeys — by perhaps 5 to 10 percent fewer calories. “It may very well be that slight calorie restriction in the control animals, plus a nutritionally balanced diet,” limits the survival difference between the groups, Mattison says.
Read more at nature.com