An interesting discovery in the field of calorie restriction research is noted here: in a short-lived species, the offspring of older mothers benefit more from a restricted calorie intake. Now, these animals also have shorter life spans and impaired reproductive fitness. This suggests that they bear a greater load of molecular damage when born, which one might expect given what is known of both aging and the health effects observed with advanced maternal age observed in many species. Since calorie restriction upregulates cellular stress responses, leading to greater maintenance and repair activities, it may well work more effectively in those animals with more damage and dysfunction to stave off. There may well be no practical outcome in human medicine that results from this finding, but it is intriguing.
There has been evidence for well over a century, from experiments done in a wide variety of animal species and from data in humans, that offspring from older mothers have shorter lifespans and lower rates of reproduction, but it wasn't well understood how a mother's age might affect other aspects of her offspring's health or response to interventions. Using rotifers, researchers studied the effects of maternal age on offspring aging and their response to dietary changes. In their experiments, they fed mother rotifers a regular diet. They then studied the offspring from young (about three days old), middle-aged, and advanced-aged (about nine days old) mothers. The offspring were fed one of three different diets: constant high food, constant low food, or alternating between high food and fasting every other day.
"These calorie-restricted and intermittent-fasting diets are known to significantly increase lifespan in rotifers and many other species, "Our study confirmed that offspring from older mothers have shorter lifespans and lower reproductive rates than offspring of younger mothers. However, offspring of older mothers, we found, have a greater increase in lifespan in response to caloric restriction than do young-mother offspring." In the offspring born from older mothers, the decreased lifespan seemed to be due to an earlier onset of aging. This early onset was delayed when those offspring were subject to caloric restriction. Even though offspring from older mothers responded more positively to caloric restriction, it did not improve their overall fitness. In evolutionary terms, "fitness" takes into consideration both lifespan and rates of reproduction. For old-mother offspring on caloric restriction or full food diets, the window for reproduction was shortened and they had half as many offspring - only 14-15, instead of the average of 25 to 30 for young-mother offspring. Caloric restriction did not rescue reproduction.