A new study published in the journal Cell Metabolism shows that cutting caloric intake by just 15 percent for two years has the ability to slow aging and metabolism and protect against age-related diseases.
A slower metabolism is most beneficial for healthy aging, and those that burn energy efficiently tend to experience the greatest longevity. Calorie restriction decreases systemic oxidative stress, which has been linked to age-related neurological conditions such as Alzheimer’s and Parkinson’s diseases, as well as cancer and diabetes.
“Restricting calories can slow your basal metabolism, and if by-products of metabolism accelerate aging processes, calorie restriction sustained over several years may help to decrease risk for chronic disease and prolong life,” said lead author Dr. Leanne M. Redman, associate professor of Clinical Sciences at Pennington Biomedical Research in Baton Rouge, La.
The study, titled CALERIE (Comprehensive Assessment of the Long-Term Effects of Reducing Intake of Energy), was the first randomized controlled trial to investigate the metabolic effects of calorie restriction in non-obese humans.
The research involved 53 healthy, non-obese men and women aged 21 to 50 who cut calories by 15 percent over a two-year period and underwent additional measurements for metabolism and oxidative stress.
The calorie reductions were calculated individually through the ratio of isotopes absorbed by the participants’ molecules and tissues. This method has been shown to accurately identify a weight-maintenance calorie level.
On average, participants in the calorie restriction group lost around 9 kilograms (19.8 pounds), although they did not adhere to any particular diet, and weight loss was not the study’s goal. No negative effects, such as anemia, excessive bone loss, or menstrual disorders were found.
In fact, the participants experienced improvements in mood and health-related quality of life.
“We found that even people who are already healthy and lean may benefit from a calorie restriction regimen,” Redman said.
Redman emphasized that the new study investigated the impact of calorie restriction on aging — not weight loss — where discussions of “fast” or “slow” metabolism most often arise. In animal studies, calorie restriction has been shown to lower core body temperature and resting metabolic rate.
“We know from mammalian studies that the smaller the mammal, the faster their metabolism and the shorter their longevity,” she said.
Many factors, such as antioxidant mechanisms and dietary and biological factors, can impact metabolism, Redman said, but current theories hold that a slower metabolism is most beneficial for healthy aging and that organisms that burn energy most efficiently should experience the greatest longevity.
“The CALERIE trial rejuvenates support for two of the longest-standing theories of human aging: the slow metabolism ‘rate of living’ theory and the oxidative damage theory,” she said. According to the oxidative damage theory, overproduction of free radicals is tied to oxidative damage to lipids, proteins, and DNA, leading to chronic diseases such as atherosclerosis, cancer, diabetes and rheumatoid arthritis.
Although the study was small and the duration short in the context of a human lifespan, biomarkers of aging were improved in study participants. In future studies, the researchers hope to establish biomarkers of human aging and also examine the effects of calorie restriction in conjunction with antioxidant foods or substances like resveratrol, which mimic calorie restriction.
Source: Cell Press