Check out our new podcast! Listen
At the Y

How Cutting Calories Expands Lifespan

John Price in white lab coat
Why do calorie-restricted mice live longer and healthier lives? BYU biochemistry professor John Price took a peek inside the mice’s cells to help solve the 90-year-old mystery.

From searching for the Fountain of Youth to buying expensive anti-aging supplements, humans have been trying to outsmart aging for a long time. And it’s no wonder, since old age is the number-one risk factor for many diseases and injuries.

In the 1930s scientists discovered that restricting calorie consumption in lab mice could slow aging down.

“There’s almost a linear increase in lifespan,” says BYU biochemistry professor John C. Price, who notes that it wasn’t just increased longevity. “Calorie-restricted mice are more energetic and [suffer] fewer diseases. . . . They’re better at maintaining their bodies—they’re younger for longer.”

Now, nearly a century later, Price’s research is helping explain the phenomenon.

In a study published in Molecular & Cellular Proteomics, Price and his fellow researchers offer a glimpse into the underlying cellular processes that contribute to aging. The key, they discovered, is ribosomes—the cellular machines that convert molecules into proteins.

Because ribosomes provide all the proteins necessary for cells to function, their maintenance is key to cell health, says Price. He likens them to a car: “The ribosome is a very complex machine, . . . and it periodically needs maintenance to replace the parts that wear out the fastest. When tires wear out, you don’t throw the whole car away. . . . It’s cheaper to replace the tires.”

“We’re getting down to the mechanisms of aging.” —John Price

The researchers found that a high-calorie diet in mice kept their ribosomes constantly at work processing proteins.

In mice with reduced calorie intake (35 percent less than the other mice), the ribosomes had occasional downtime to make repairs. Although the decreased speed lowers protein production, well-maintained ribosomes can produce higher-quality proteins, and higher-quality proteins mean healthier cells and more-youthful bodies.

The discovery was made possible by an observational method that developed from Price’s postdoctoral studies at the University of California, San Francisco. It involved giving mice water with molecular isotope markers and then using mass spectrometry to determine how many of those molecules were present as the ribosomes created new proteins.

Despite the connection between calorie restriction and increased lifespan, Price doesn’t recommend that people severely reduce calories in an effort to stay forever young. “We know from anorexia that you can shorten your life span by not having enough nutrients,” he says.

His hope is that this and future research will show how food choices affect the body on the cellular level.

“Food isn’t just material to be burned— it’s a signal that tells our body and cells how to respond,” Price says. “We’re getting down to the mechanisms of aging, which may help us make more-educated decisions about what we eat. ”