Penn State researchers have discovered another layer of complexity in the puzzle of how nutrition affects aging. A new study led by experts at Penn State’s College of Health and Human Development examined how calorie restriction affects a person’s telomeres – regions of the genetic base that act as protective caps at the ends of chromosomes. . The researchers’ findings were published in the journal ‘Aging Cell’.
Researchers analyzed data from a two-year trial on calorie restriction in humans and found that people who reduced their calories lost telomeres at different rates than the control group, even though both groups had approximately the same length. Ended the study with telomeres of. Calorie restriction of 20 percent to 60 percent has been found to promote longer life in many species. During human life, each time a person’s cells replicate, some telomeres are destroyed when the chromosomes are copied into the new cell. When this happens, the total length of the cell’s telomeres becomes shorter. After cells replicate enough times, the protective cap of telomeres is completely destroyed. Then, the genetic information in the chromosome may be damaged, preventing future reproduction or proper functioning of the cell. A cell with a long telomere is functionally younger than a cell with a short telomere, meaning that two people with the same chronological age can have different biological ages depending on the length of their telomeres.
According to Idan Shalev, associate professor of biobehavioral health at Penn State, specific aging factors, stress, disease, genetics, diet and more can impact how often cells replicate and what length telomeres maintain. Shalev led researchers who analyzed genetic samples from the National Calorie Study – the first randomized clinical trial of calorie restriction in humans. Shalev and his team sought to understand the effect of calorie restriction on telomere length in people. Because telomere length reflects how quickly or slowly a person’s cells are aging, examining telomere length may help scientists identify one way in which calorie restriction may slow aging in humans. Can slow down.
“There are many reasons why calorie restriction might extend human lifespan, and this topic is still being studied,” said Waylon Hastings, who earned a doctorate in biobehavioral health at Penn State in 2020 and was the lead author of this study. “A primary mechanism through which life is extended is related to metabolism in the cell. When energy is consumed within a cell, the waste products from that process cause oxidative stress that can damage DNA. And can otherwise break down the cell. When a person’s cells consume less energy however, because of calorie restriction, there are less waste products, and the cell does not break down as quickly.”
Researchers tested the telomere length of 175 research participants using data from the beginning of the CALERIE study, one year into the study, and the end of the study after 24 months of calorie restriction. About two-thirds of the study participants participated in calorie restriction, while one-third served as a control group.
During the study, results showed that telomere loss changed the trajectory. In the first year, participants who were restricting calorie intake lost weight, and they lost telomeres at a faster rate than the control group. After one year, the weight of participants on calorie restriction stabilized, and calorie restriction continued for the next year. During the second year of the study, participants on calorie restriction lost telomeres more slowly than the control group. At the end of two years, the two groups had converged, and the telomere length of the two groups was not statistically different.
“This research highlights the complexity of how calorie restriction affects telomere loss,” Shalev said. “We predicted that telomere loss would be slower in people with calorie restriction. Instead, we found that people with calorie restriction lost telomeres faster at first and then more slowly after their weight stabilized.” Shalev said the results raised many important questions. For example, what would have happened to telomere length if data had been collected for another year? Study participants are scheduled for 10-year follow-up data collection, and Shalev said he was looking forward to analyzing that data when it becomes available.
Despite the ambiguity of the results, Shalev said the potential health benefits of calorie restriction in humans are promising. CALERIE Data Previous research has shown that calorie restriction can help reduce harmful cholesterol and lower blood pressure. According to Shalev and Hastings, for telomeres, the two-year time frame was not long enough to show benefits, but they may still emerge.
Three of Shalev’s trainees, Hastings, current graduate student Qiaofeng Ye, and former postdoctoral scholar Sarah Wolf, led the research under Shalev’s guidance.
