Animal studies have suggested that restricting calories may prolong life, and this effect may also be seen in humans. Telomeres, the protective lengths of DNA at the end of chromosomes, shorten as cells age. Researchers from Penn State University analyzed data from the CALERIE trial to investigate whether caloric restriction might slow this process. They found that caloric restriction initially accelerated telomere shortening but then slowed the process. After 2 years, both the caloric restriction group and the control group had lost similar telomere length. This highlights the importance of long-term studies to fully understand aging-related processes.
The CALERIE trial recruited 220 participants, aged between 21 and 50, who were healthy and had a body mass index (BMI) between 22 and 28 kg/m2. Two-thirds of the participants committed to 25% calorie restriction for 24 months, with the remaining participants as controls. The research advised all participants to engage in moderate exercise and provided meals for the caloric restriction group initially. The average calorie restriction achieved was 11.9%. Weight loss occurred in the caloric restriction group during the first 12 months, stabilizing in the second year. Previous analyses of the CALERIE data have shown some health benefits of caloric restriction but also negative effects on bone density and muscle mass.
Over the 2-year study, there was no significant difference in telomere length change between the caloric restriction and control groups. The researchers found that telomere length decreased faster in the caloric restriction group in the first 12 months, but the rate of decrease slowed to a lower rate than that of the control group in the second year. This suggested that the stress of weight loss accompanying caloric restriction may have initially accelerated telomere shortening but then slowed as new homeostatic norms were established. The team plans to follow up with the cohort at 10 years to observe telomere length change over a longer period.
It is known that diet and exercise can affect health and aging. Primary aging is the natural aging process, while secondary aging results from excess food intake, lack of exercise, and disease, accelerating the aging process. Animal studies have shown that restricting calorie intake can slow this secondary aging process, reduce disease, and prolong life. However, the exact mechanisms underlying these effects are not yet fully understood. Research in mice has shown that caloric restriction can slow the shortening of telomeres and prolong lifespan, prompting further investigation into whether a similar effect can be observed in humans.
The study conducted by Penn State University analyzed data from the CALERIE trial to investigate the effects of caloric restriction on telomere length. The initial findings showed that caloric restriction accelerated telomere shortening, but the rate of decrease slowed in the second year. This complexity highlights the need for longer-term studies to fully understand the impact of caloric restriction on aging-related processes. Telomere dynamics is just one factor in aging, and future research should combine different fields to create personalized approaches for healthy aging and disease prevention. The study emphasizes the complex relationship between genes, the environment, and lifestyle choices in shaping health outcomes and highlights the importance of long-term studies to fully understand the effects of caloric restriction on age-related processes.
