Posted on May 23, 2017, 6 a.m.
Research analysis finds that cutting calories works at a physiological level to slow biological aging.
The study was lead by Daniel Belsky, Ph.D. an assistant professor of medicine at the Duke University School of Medicine. Previous research has shown that calorie restriction hinders the aging process in mice, worms, and flies. The question is to what extent such restriction has on the biological aging process in human beings. Biological aging is best defined as the slow but progressive deterioration of the human body's systems over time. If the biological aging rate can be slowed through intervention, it might be possible to delay or prevent the onset of numerous age-related disabilities and diseases.
About the Analysis
Belsky and her team of researchers studied data available to the public from a trial known as “CALERIE”. The National Institute on Aging conducted this study involving 220 individuals. They were randomized for a calorie restriction of 25 percent or allowed to maintain their current dietary intake. The calorie restriction group was comprised of 145 people. Their calories were reduced by 12 percent across the two-year study. The other group, in which calories were not restricted, was comprised of 75 individuals. The research team studied data from both groups at the beginning of the study. Follow-ups took place at the one-year point as well as the two-year anniversary.
One method calculated the biological age for participants according to their chronological age as well as the biomarkers that gauge the function of the liver, kidneys, immune system, metabolic system, and cardiovascular system. Hemoglobin levels, systolic blood pressure, and cholesterol were also accounted for. At the beginning of the study, both groups had similar biological ages as determined by the measure described above. The average biological age of the participants was 37 while the average chronological age was 38.
Once the one-year follow-up point was reached, those in the restricted calorie group had an average biological age increase of 0.11 years. The participants who continued their normal dietary intake experienced an average biological age increase of 0.71 years at the one-year follow-up. The difference between these groups was statistically meaningful, showing that restricting calories really did deter the biological aging rate.
The research team also performed another analysis that quantified biological aging as the level of physiological deviation from a benchmark defined by young and healthy individuals from a distinct data set. At the beginning of the trial, the maintenance and calorie-restricted groups deviated the same level on average from the benchmark point. However, at the one-year and two-year follow-up points, the average deviation among the maintenance group stayed the same. The group in which calories were restricted gradually became more similar to the healthy and young benchmark reference point.
The findings were consistent with the mitigated aging researchers found in the group with restricted calories when the biological age calculation method was applied. Interventions to offset or control aging are at the center of medical research.
This was the first study to gauge whether the restriction of calories could mitigate measured biological aging in human beings in a randomized setting. This study applied the measures of physiologic age described above and demonstrated their value as well as the apparent value provided by restricting calories to slow the aging process. The results suggest a template to develop and study therapies meant to copy the effects of restricting calories to ward off chronic diseases.
The study was published online May 22 in the Journals of Gerontology, Series A: Biological Sciences and Medical Sciences.