LA JOLLA, Calif. — Right around this time of the year is when millions tend to give up on their ambitious New Year’s resolutions. If you had resolved to cut back on the calories this year, here’s some extra incentive: a new study finds restricting your caloric intake will slow cellular aging, reduce inflammation, lower your risk of age-related diseases, and promote an overall longer life. Suddenly, it totally seems worth it to skip that midnight snack.
Researchers from the Salk Institute for Biological Studies came to their conclusions after performing diet experiments on a group of rats.
“We already knew that calorie restriction increases life span, but now we’ve shown all the changes that occur at a single-cell level to cause that,” says Juan Carlos Izpisua Belmonte, co-corresponding author of the new paper, and a professor in Salk’s Gene Expression Laboratory, in a release. “This gives us targets that we may eventually be able to act on with drugs to treat aging in humans.”
Try as we all might to avoid growing old, aging is the number one risk factor for many awful diseases such as cancer, dementia, and diabetes. However, cutting back on calories has been shown to help mitigate one’s risk of developing such disorders in old age. That being said, up until now its been largely unknown how a lower calorie intake influences the human body on a cellular level.
For this new study, rats eating a strict diet of 30% fewer calories than normal were compared to another group of rats eating a typical diet. Both groups of rats were fed these diets from the age of 18 months old to 27 months old. In human years, that time period would roughly represent someone following a strict low-calorie diet from the age of 50 to 70 years old.
At the beginning and end of the diet period, researchers isolated and analyzed 168,703 cells from 40 cell types across both rat groups. These cells came from a variety of areas in the rats’ bodies; brain, muscle, liver, skin, kidney, bone marrow, and fat tissues. Then, in each isolated cell, advanced technology was used to measure genetic activity, as well as the overall composition of the cell types.
Astoundingly, many of the negative changes that occurred in the rats on the normal diet as they grew older didn’t appear in the rats on a stricter diet. Even by the time the dieting rats reached old age (27 months old), their cells appeared much younger. In all, 57% of the age-related changes observed in the normally eating rats were absent from the dieting rats.
“This approach not only told us the effect of calorie restriction on these cell types, but also provided the most complete and detailed study of what happens at a single-cell level during aging,” says co-corresponding author Guang-Hui Liu, a professor at the Chinese Academy of Sciences.
Many of the cells that appeared to be especially influenced by diet were connected to inflammation, immunity, and lipid metabolism.
“The primary discovery in the current study is that the increase in the inflammatory response during aging could be systematically repressed by caloric restriction” explains co-corresponding author Jing Qu, also a professor at the Chinese Academy of Sciences.
“People say that ‘you are what you eat,’ and we’re finding that to be true in lots of ways,” concludes co-author Concepcion Rodriguez Esteban. “The state of your cells as you age clearly depends on your interactions with your environment, which includes what and how much you eat.”
The study is published in Cell.