In mice, caloric restriction has been found to increase aging but obviously mice are not little people, and mice are weaned on a starvation diet. That cannot and will never happen in humans. Yet restricting calories even by 20 percent has been shown to promote longer life in animal models.
As we age, our cells replicate, but some telomeres are lost when chromosomes are copied to the new cell, the telomeres become shorter and after enough replication, the protective cap of telomeres completely dissipates. If the genetic information in the chromosome is damaged, future reproduction or proper function of the cell may be prevented. A cell with longer telomeres is functionally younger than a cell with short telomeres, meaning that two people with the same chronological age could have different biological ages depending on the length of their telomeres.
Credit: Hey Mr Glen, CC BY-NC
Typical aging, stress, illness, genetics, diet and more can all influence how often cells replicate and how much length the telomeres retain and a new analysis sought to see what might work in maintaining longer telomeres. The authors looked at genetic samples gathered in a two-year randomized clinical trial of caloric restriction in humans, the national CALERIE study, and found that people who restricted their calories lost telomeres at different rates than the control group, though both groups ended the study with telomeres of roughly the same length.
Of the 175 research participants in the CALERIE study, two-thirds participated in caloric restriction, while one-third served as a control group. They looked at data from the start of the study, one year into the study and after 24 months. Results were that telomere loss changed trajectories. Over the first year, participants who were restricting caloric intake lost weight, and they lost telomeres more rapidly than the control group. After a year, the weight of participants on caloric restriction was stabilized, and caloric restriction continued for another year. During the second year of the study, participants on caloric restriction lost telomeres more slowly than the control group. At the end of two years, the two groups had converged, and the telomere lengths of the two groups was not statistically different.
So there's not much for humans yet, we're still stuck in the 1960s talking about oxidation and reduction and antioxidants in mitochondria and DNA and cells. Science marches on.
