Researchers have been able to reverse the age-related loss of functionality in intestinal stem cells in a very simple way. A 24-hour fast has been shown to dramatically improve how these important cells regenerate in both old and young mice.

The study, reported in Cell Stem Cell, looked at the effect of diet on the gut cells of young and old mice. What the researchers discovered was that after just a single day of fasting, the cells underwent a switch in behavior. They stopped burning carbohydrates and started burning fat. And once the cells started burning fatty acids their functionality got better.

“Intestinal stem cells are the workhorses of the intestine that give rise to more stem cells and to all of the various differentiated cell types of the intestine. Notably, during aging, intestinal stem function declines, which impairs the ability of the intestine to repair itself after damage,” senior author professor Omer Yilmaz, from MIT’s Koch Institute for Integrative Cancer Research, said in a statement. “In this line of investigation, we focused on understanding how a 24-hour fast enhances the function of young and old intestinal stem cells.”

What the team realized is that once the mice began fasting, certain transcription factors – proteins that help convert DNA to RNA – activated. They are called PPARs. When they are switched off the cells can’t burn fatty acids, and the analysis showed that when this happens the cells can no longer boost regeneration. The reverse is also true. The team activated the PPARs while the mice were not fasting and still got the beneficial effect.

“That was also very surprising,” co-lead author Chia-Wei Cheng added. “Just activating one metabolic pathway is sufficient to reverse certain age phenotypes.”

The findings are really important. The discovery that fasting helps the intestines regenerate is important in its own right, but combining it with the potential of simply using a drug to obtain the same effect makes this a key study for medical interventions on the lower digestive system. It could, for example, help patients recovering from chemotherapy or gastrointestinal infections.

The team is now curious to find out whether cells in other parts of the body also have this capability. Fasting or the use of the drug could boost tissue longevity in many different organs.