A calorie-restricted diet may slow aging in healthy adults, science shows


Eating fewer calories appears to slow the rate of aging and increase longevity in healthy adults, according to a study published Thursday in the journal. Nature Aging.

The study, which was funded by the National Institute on Aging, part of the National Institutes of Health, is the first randomized controlled trial to look at the long-term impact of caloric restriction.

It adds to an already large body of evidence that a A calorie-restricted diet can provide substantial health benefits, including slowing aging, said study lead author Dan Belsky, an assistant professor of epidemiology at the Columbia University Mailman School of Public Health in the city. from New York.

«The main takeaway from our study is that it is possible to slow the rate of biological aging, and that it may be possible to do so through lifestyle and behavior modification,» Belsky said.

In a two-year phase 2 clinical trial, 220 adults were randomized to reduce their caloric intake by up to 25% (500 calories for people who typically eat 2,000 calories a day) or to make no changes to their diet . The participants had a body mass index, or BMI, that ranged from 22 to 27.

People in the calorie restriction group were given three prepared meals each day for the first month to familiarize themselves with portion sizes. Behavioral counseling on diet was also provided for the first 24 weeks. Participants not in the calorie restriction group were not told how much to eat and did not receive any advice.

Dr. Evan Hadley, director of the division of geriatrics and clinical gerontology at the National Institute on Aging, said most people in the calorie restriction group only ended up reducing their daily caloric intake by about 12%.

“But that 12% was enough to have significant changes,” he said.

To measure the rate of aging, the researchers used an algorithm to see how certain DNA biomarkers in the blood changed over time.

The algorithm was based on previously acquired data from about 1,000 people who were followed for 20 years to see how quickly the function of their organs, including the heart, liver, kidneys and lungs, declined as they aged, Belsky said. . The algorithm, he added, acted as a kind of «speedometer,» helping to measure how quickly the study participants were aging.

The researchers found that people who cut their calories slowed their aging rate by 2-3%, compared to people who ate a normal diet.

That translates, Belsky said, into a 10% to 15% reduction in the chance of dying prematurely.

«We all have the power to change the trajectories of aging,» he said.

Whether the slowdown in aging will hold after two years is not yet known, Hadley said. Study participants were not followed up after the two-year intervention. A separate study, also funded by the agency, plans to look at the effects of a calorie-restricted diet after 10 years, she added.

Still, Hadley said, the new study reinforces previous research findings that some Caloric restriction can promote health benefits, including a longer, healthier life.

Researchers don’t yet know exactly why cutting calories seems to slow the aging process, although there is evidence that calorie restriction causes changes at the cellular level, Belsky said.

«It can induce sort of survival response mechanisms in the body that have the effect of cleaning up intracellular junk,» he said. “It’s a signal to the body that says, ‘Hey, pay attention. There are resource stresses in the environment. We need to make sure that we are using all available resources in the most efficient way.”

Pankaj Kapahi, a researcher at the Buck Institute for Research on Aging, said that along with caloric restriction, exercise and a balanced diet are also important factors to consider for aging. He was not involved in the investigation.

«Multiple interventions are needed to see the full health effects,» he said.

Kapahi added that the study findings don’t mean people should starve themselves, saying that could lead to malnutrition and poor mental health.

«Calorie restriction has to be done at a marginal level,» he said.

Valter Longo, a biochemist and director of the Longevity Institute at the University of Southern California, said limiting calories for long periods of time can be harmful.

Animal studies, for example, have shown that long-term caloric restriction is associated with a risk of reduced muscle strength, slower metabolism and an impaired immune system, said Longo, who was not involved in the study.

“It can cause powerful anti-aging effects, but also likely some degree of brittleness or other issues that may not be as beneficial,” he said.

Hadley cautioned against overinterpreting the results, saying caloric restriction might not be for everyone, including those with multiple underlying conditions. He advised talking to a doctor before going on a calorie-restricted diet.

«It’s not like this is somehow this universal key to aging and therefore it’s going to slow everything down,» he said.

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