Calorie restriction’s link to aging causes divide in scientific community
OSWEGO, N.Y — Calorie restriction can slow the pace of aging in healthy adults by 2 to 3% which is a 10 to 15% reduction in mortality rate, according to a recent study conducted by the Columbia Aging Center.
“I think moderate calorie restriction might help reduce chronic disease risk, thereby increasing the possibility that someone could live a longer life, but there are so many other factors involved that it’s hard to make a concrete connection between two factors,” said Erin Kelly, a registered dietitian and program director for Dietetics and Nutrition at Utica University.
The CALORIE™ Phase-2 randomized controlled trial is the first investigation of long-term calorie restriction and its effects on healthy, non-obese adults, with funding provided by the U.S. National Institute of Aging.
The trial consisted of 220 healthy men and women who were instructed to cut back their calorie intake by 25% for two years.
Associate professor of epidemiology at Columbia University’s Mailman School of Public Health and senior author on the trial, Daniel Belsky, and his team tested these individuals before the trial began and at the 12- and 24- month follow ups. The team then analyzed these blood samples for DNA methylation marks, which are chemical tags throughout DNA that regulate certain genes and are known to impact aging.
These findings were then measured using three different forms of epigenetic clocks, which are biological age estimators. A follow-up on trial participants is currently ongoing in order to analyze some longer term effects of calorie restriction.
Research on calorie restriction is not new by any means, though most of the past trials have used animals as test subjects. Despite decades worth of research, the scientific community has remained divided on if calorie restriction actually slows aging.
Some researchers doubt the reliability of the use of epigenetic clocks. According to a study entitled Clock Work: Deconstructing the Epigenetic Clock Signals in Aging, Disease, and Reprogramming, performed by a group of scientists from Yale University, a major drawback in the application of epigenetic clocks is their lack of “lack of mechanistic understanding.”
“[Epigenetic clocks] are comprised of disparate parts, each with their own causal mechanism and functional consequences,” according to the Clock Work study. Epigenetic clocks measure a number of factors and this makes it difficult to determine the underlying biology causing aging.
Kelly noted the drawbacks that calorie restriction can have on the body such as reduced energy, trouble regulating your body’s chemical reactions due to a lack of macro- and micronutrients and slower metabolism.
“The less energy we give our body, the slower it must operate in using that energy,” Kelly said.
The health benefits related to calorie restriction are usually linked to a lowered risk of certain illnesses that have the potential to increase an individual’s mortality rate.
“Calorie restriction will lead to weight loss. In some circumstances, weight loss is the desirable outcome when facing certain non-communicable diseases such as Type 2 diabetes, Hypertension and Cardiovascular disease,” said Hailee Dumont, a nutrition sciences master student at King’s College.
Although Dumont does not believe that there is a direct connection between calorie restriction and slow aging she does see weight loss as a result of calorie restriction as having some potential anti-aging benefits.
According to an article written by Harvard scholar Isabella Grabski, the CALORIE™ trial alone is “not enough evidence to conclude that calorie restriction should enter standard medical practice.”
Research topics such as this also create concern regarding those struggling with unhealthy food relationships or eating disorders.
“The term ‘calorie restriction’ could easily be misinterpreted. Some individuals may hear this, and restrict their calories below their basal energy expenditure (BEE) which could have potentially harmful long-term effects,” said Dumont.
Kelly stressed the importance of sharing and reporting on this information with the utmost caution so as not to spread the wrong message. Though she does believe that this information remains mostly within the academic scientific community.
“Because the research is generally pretty scientifically detailed, many people in the general population aren’t seeing it, so it wouldn’t necessarily have a negative effect in a broad sense,” said Kelly.
Clinical research on eating disorders has shown that there are a number of negative consequences of excessive calorie restriction, meaning that in order to continue these human trials participants would have to be screened carefully to ensure that there are no ethical concerns regarding their safety.
While the specific benefits of calorie restriction and its link to the aging process are still widely debated throughout the scientific community, these trials do provide some useful information.
“Understanding why caloric restriction seems to promote longevity could shed deeper insight into the aging process itself. Addressing this mystery may help lead to other anti-aging efforts, even if this particular calorie restriction work never makes it out of the lab,” said Grabski.