Researchers from Penn State University have conducted a study linking dieting to aging by examining the impact of calorie restriction on telomeres, which are protective structures at the ends of chromosomes.

Caloric restriction affects telomere loss rate

Published in Aging Cell, their findings suggest that while calorie restriction affects telomere loss rates, overall telomere length remains similar between those who restrict calories and the control group. Previous research indicates that calorie restriction can extend lifespan in various animals.

Cell division results in the gradual loss of telomeres, the protective caps of chromosomes, leading to shortening of telomeres with each division. As telomeres diminish, genetic material becomes vulnerable to damage, hindering cell reproduction and function, a process known as cellular senescence. Telomeres dictate cellular aging, with longer ones indicating youthfulness. Thus, individuals of the same chronological age may possess varying biological ages determined by telomere length.

Various factors, including aging, stress, illness, genetics, and diet, can influence cell replication frequency and telomere length.

The study, led by Waylon Hastings, a 2020 Penn State biobehavioral health Ph.D. graduate, explores the potential of caloric restriction to extend human lifespan. Hastings suggests that reduced energy consumption within cells, a key mechanism of caloric restriction, leads to decreased oxidative stress and less damage to DNA, thus slowing down cellular breakdown and potentially prolonging life.

Telomere loss is quicker in individuals on calorie restriction

The telomere lengths of 175 research participants were assessed over a 24-month period, using data from the CALERIE study—a pioneering trial investigating calorie restriction in humans. Participants were divided into two groups: around two-thirds underwent caloric restriction, while the rest served as the control group.

In the study, participants who restricted calories lost weight and experienced quicker telomere loss compared to the control group in the first year. However, after one year, their weight stabilized, and the calorie restriction continued for another year. In the second year, the rate of telomere loss among calorie-restricted participants slowed compared to the control group. At the end of two years, there was no statistically significant difference in telomere lengths between the two groups.