Fasting Helps Prevent Infection In Mice

A new study conducted on mice found fasting before and during exposure to Salmonella enterica bacteria protected mice from developing full-blown infections. Study researchers believe the protection is in part due to changes in the gut microbiome of the mice. Researcher Bruce Vallance and colleagues conducted the study at the University of British Columbia, Canada.

In the study, mice fasted 48 hours before and during oral infection with Salmonella enterica serovar Typhimurium, a common cause of foodborne illness in humans. Fasting decreased the signs of bacterial infection compared to mice that were fed. In addition, researchers found mice that fasted eliminated nearly all intestinal tissue damage and inflammation.

However, when fasted animals were fed again for a day after their fast dramatic increases in salmonella numbers was noted and increased invasion into the intestinal wall. Despite an increase in bacteria numbers and intestinal wall invasion, associated inflammation was still reduced compared to normal. The same results were not seen in the study if the mice were given salmonella intravenously rather than orally.

Analysis of the microbiome of the mice showed significant changes associated with fasting and protection against infection. Fasting did not protect germ-free mice that were bred to lack a normal microbiome from infection with salmonella. The results suggest that some of the protection seen in fasting mice was due to the effect of fasting on the microbiome.

Researchers also conducted experiments using a different bacteria, called Campylobacter jejuniand, confirming that the effects of fasting aren't limited to salmonella. Researchers say that their work highlights food's role in regulating interactions between the host, enteric pathogens, and the gut microbiome. When food is limited, it appears the microbiome sequesters nutrients that remain, preventing pathogens from acquiring the energy they need to infect the host. While more research is needed, the team believes adjusting food intake could be used therapeutically to modulate infectious diseases in the future.