Reducing calorie intake has extended lifespan in animals including mice, rhesus monkeys, and fruit flies. In some studies, the animals also remained healthier for longer. But severe calorie restriction can come with serious costs. Mice placed on a diet with 40% fewer calories, for instance, become more vulnerable to infections, reproduce less successfully, and show impaired growth.
That has left scientists with a difficult question: Could humans gain some of the longevity benefits of calorie restriction without experiencing those harmful effects? A new study, published in Nature Aging, points to a possible answer involving an immune protein called complement component 3 (C3).
Yale researchers have previously shown that people who followed moderate calorie restriction, cutting calorie intake by 14% for two years, developed stronger immune defenses without experiencing problems related to growth or reproduction.
"This concept demonstrates that aging is actually malleable and a process that can be targeted," says senior author Vishwa Deep Dixit, PhD, Waldemar Von Zedtwitz Professor of Pathology, professor of immunobiology and of comparative medicine, and director of the Yale Center for Research on Aging (Y-Age) at Yale School of Medicine.
