A new study reveals that reducing calorie intake could slow the rate of aging according to certain biomarkers. Study participants who reduced their calorie intake as part of a carefully designed and followed dietary program slowed their rate of aging, evidenced by certain epigenetic biomarkers, by 2-3% after two years. Similar effects had already been observed in some animal trials, although other studies revealed an adverse effect. A new study has investigated whether cutting calories could be a way to slow aging. In a randomized, controlled human study, the first of its kind, scientists looked at a single biomarker to show it’s possible.
In promising results, researchers in a recent study found that cutting calories caused participants to slow down by 2-3% as certain molecules attached to their DNA, or their epigenome, age. The authors cite previous research that equates this 2-3% decrease in rate to a 10-15% reduction in mortality risk. This figure is similar to the risk reduction expected when a smoker quits. The study of calorie reduction as a way to slow aging is a test of the geroscience hypothesis. This suggests that by slowing or reversing the molecular changes associated with aging, a person’s lifespan may be extended and they may be able to avoid serious chronic diseases.
The study is published in Nature Aging.
Carefully controlled calorie intake
The results of this study are exciting because they suggest that it may be possible to slow the rate of aging in humans. It opens many doors to what we might be able to do in the years to come. Researchers in the current study used a precision calorie reduction and scoring system called “CALERIE.” CALERIE is the acronym for “Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy”. It is very different from what one would find in a weight loss diet based on reducing caloric intake.
The authors note that the calorie reduction in the study was carefully designed to decrease energy intake without depriving participants of essential nutrients. It was a complex intervention that involved teams of nutritionists and dietitians working with participants to design effective diets and doctors monitoring participants’ health to ensure safety. The study trial took place at three sites, and initially involved 220 healthy men and women. The men were 21-50 years old and the (premenopausal) women were 21-47 years old. Over two years, 145 participants were tasked with achieving a 25% calorie reduction on the CALERIE program from their baseline calorie intake level. Forty-five people served as a control group.
The number of individuals who eventually completed the trial was 117 people in the CALERIE group and 68 in the control group.
Measurement of 3 biomarkers of aging
To measure the effects of CALERIE, the researchers relied on three biomarkers of aging, or “aging clocks”: PhenoAge, GrimAge and DunedinPACE. All are based on DNA methylation which can be measured in blood samples. Human beings live a long time. Biomarkers can therefore give us a first clue as to whether the intervention has the effect we want to test.
PhenoAge and GrimAge both claim to estimate a person’s chronological age based on their current biology. This would be the age at which they would be considered standard. DunedInPace, on the other hand, measures how fast a person ages.
DunedInPace is something of a speedometer of aging. PhenoAge and GrimAge are comparable to snapshots. These measurements only account for a portion of biological aging, and are unlikely to be an accurate overall measure of “biological age” or “biological aging rate”.
The study found that calorie reduction had an effect on the DunedInPace biomarker, but not on PhenoAge or GrimAge measurements. Two years may not be enough to show a measurable change in PhenoAge or GrimAge. For static biomarkers of aging, we just don’t know how long it would take to intervene to see an effect. In small, uncontrolled trials, some interventions have shown changes over short periods of time, and others have not.
Evidence not yet definitive
This is good suggestive evidence that caloric restriction can alter some aspects of biological aging in humans, as has been known for decades in laboratory animals.
The results of animal testing were mixed, and about a third of genetic groups have no positive effect on lifespan or have their lifespan shortened” by calorie reduction.
