A team of researchers has found that restricting the diets of rhesus monkeys helped them live longer and with less health problems. Controlling how many calories the monkeys consumed increased lifespan and reduced some effects of aging. The helpfulness of a restricted diet varied with age, sex, and other factors. The details are in a paper that was just published in the journal Nature Communications.
Rhesus monkeys (Macaca mulatta) are good models for studying aging and other medical processes in humans. They share most of our genes and most aspects of their anatomy match up with ours. Although previous studies had examined the effects of restricted diets on aging and lifespan in rhesus monkeys, the two largest studies conflicted. In one study, restricting calorie intake greatly increased lifespan. In a later study, the researchers found no connection between restricted diets and rhesus monkey lifespans. This inconsistency prompted a team of scientists to reevaluate the question of whether or not calorie intake affects lifespan in rhesus monkeys.
Scientists from the University of Wisconsin-Madison collaborated with the National Institute on Aging to design a new experiment to determine if calorie restriction actually affected lifespan in rhesus monkeys. Both organizations had conducted the previous studies but teamed up to figure out the truth. The researchers analyzed data from about 200 individual monkeys that had been fed natural but controlled diets for years. Some of the monkeys had their calories restricted while others ate the same diets but were given more food.
The researchers found that rhesus monkeys in the caloric restriction group lived significantly longer, around two or three years more than monkeys in the control group. The monkeys with restricted diets also had less health problems, such as glucoregulatory dysfunction and increased body fat. These dietary benefits only occurred in adult and aging monkeys, not immature animals. Interestingly, female monkeys were not affected as much by extra body fat—a finding that shows differences in dietary effects between the sexes. The researchers concluded that restricting calorie intake increases the lifespans of rhesus monkeys.
The team’s findings may also apply to humans since we have so much in common with rhesus monkeys and other primates. More research will be needed to identify all of the benefits of dietary calorie restriction.
Mattison et al. Caloric restriction improves health and survival of rhesus monkeys. Nature Communications (2017).