Researchers: Cutting Calories May Help Monkeys Live Longer

PHILADELPHIA (CBS) -- A report based on work from two separate research teams adds to evidence that cutting back on calories helps rhesus monkeys live healthier, longer lives.

The research teams that collaborated are from the University of Wisconsin-Madison and the National Institute on Aging (NIA).

Their findings were published in the journal Nature Communications.

Researchers say in 2009, a UW–Madison study team reported significant benefits in survival and reductions in cancer, cardiovascular disease, and insulin resistance for monkeys that ate less than their peers.

However, in 2012, a NIA study team reported no significant improvement in survival, but did find a trend towards improved health.

Scientists say they think they now know why the studies had different results.

Researchers say the animals in the studies had their diets restricted at different ages. Comparative analysis found that eating less is only beneficial in adult monkeys, not young primates.

Secondly, in the original study the NIA control monkeys ate less than the Wisconsin control group. Scientists say this lower food intake was associated with improved survival compared to the Wisconsin controls.

Researchers say it seems that small differences in food intake could meaningfully affect aging and health.

Another difference between the studies was diet composition. The NIA monkeys ate naturally sourced foods and the UW–Madison monkeys ate processed food with higher sugar content.

Unsurprisingly, the UW–Madison control animals weighed more than the control monkeys at NIA. Researchers say this proves that what is eaten makes a difference for fat mass and body composition.

The research team also found differences when it came to the gender of the monkeys. Females seemed to be less vulnerable to adverse effects of body fat than males.

Researchers say the new insight appears to be particularly important in primates and likely is translatable to humans.

Researchers concluded that restricting calories does seem to affect aging, but for primates, their age, diet and sex must all be factored in to realize the full benefits.