Ageing may seem to be an unavoidable part of life, but scientists are closer than ever to developing a cure or intervention to combat the effects of time.

Here is what the new research says about aging and what can be done to slow the pace of aging in healthy adults:

An international team of researchers headed by the Butler Columbia Aging Center at Columbia University’s Mailman School of Public Health has shown that calorie restriction may slow the process of aging in healthy individuals in a first-of-its-kind randomized controlled experiment. 

The CALERIE™ intervention slowed down the rate of aging, as determined from the blood DNA methylation of subjects by using the algorithm DunedinPACE (Pace of Aging, Computed from the Epigenome).

According to other studies, the intervention’s impact on DunedinPACE was equivalent to a smoking cessation intervention in that it caused a 2-3% slowing of the aging process and a 10-15% decrease in mortality risk. 

The findings were published online in Nature Aging journal.

“In worms, flies, and mice, calorie restriction can slow biological processes of aging and extend healthy lifespan” remarks senior author Daniel Belsky. “Our study aimed to test if calorie restriction also slows biological aging in humans.”

In the study, 220 healthy men and women were assigned at random to either a diet with a calorie restriction of 25% or a regular diet for a period of two years at three different locations in the United States.

Belsky’s team examined blood samples taken from trial participants at pre-intervention baseline and after 12- and 24-month follow-ups in order to quantify biological aging in Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy or CALERIE Trial participants.

“Humans live a long time,” adds Belsky, “so it isn’t practical to follow them until we see differences in aging-related disease or survival. Instead, we rely on biomarkers developed to measure the pace and progress of biological aging over the duration of the study.”

The team looked at the methylation marks on white blood cell DNA. It is known that DNA methylation marks, which are chemical tags on the DNA sequence and govern the expression of genes, change as a result of the natural process of aging.

Belsky and colleagues’ initial investigation focused on three measures of the DNA methylation data, sometimes referred to as “epigenetic clocks.”

Biological age, or the chronological age at which a person’s biology would look “normal,” is estimated by the first two clocks, PhenoAge and GrimAge.

These indicators may be seen as “odometers” that provide a fixed evaluation of a person’s biological age.

The third thing the researchers looked at was DunedinPACE, which measures how fast a person is getting older or how fast their body is getting worse over time. DunedinPACE may be compared to a speedometer.

There were no impacts of the intervention on other epigenetic clocks, in contrast to the outcomes for DunedinPace, according to co-author Calen Ryan. 

“The difference in results suggests that dynamic ‘pace of aging’ measures like DunedinPACE may be more sensitive to the effects of intervention than measures of static biological age.”

The results of the study “found evidence that calorie restriction slowed the pace of aging in humans” adds Ryan.

But cutting calories is probably not a good idea for everyone.

These “findings are important because they provide evidence from a randomized trial that slowing human aging may be possible. They also give us a sense of the kinds of effects we might look for in trials of interventions that could appeal to more people, like intermittent fasting or time-restricted eating.”

Now, people who took part in the trial are being tracked to see if the intervention had any long-term effects on healthy aging. Other studies have found that a slower DunedinPACE is linked to a lower risk of heart disease, stroke, disability, and dementia.

Daniel Belsky and colleagues from the University of Otago and Duke University created DunedinPACE. The researchers behind DunedinPACE used the data obtained from the Dunedin Longitudinal Study as the basis for their development. This study is considered a landmark in the field of human development and aging, following the lives of 1000 individuals born between 1972 and 1973 in Dunedin, New Zealand.

Initially, researchers examined the pace of change in 19 biomarkers throughout 20 years of follow-up to create a single composite measure of the Pace of Aging. The 20-year Pace of Aging was then reduced into a single time point DNA methylation blood test using machine learning methods.

The DunedinPACE method yields numbers that are a measure of the rate of aging; these values are years of biological aging experienced in a single year.

Source: Nature Aging

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