Does Fasting Help Protect Against Infection?

Most people feeling under the weather, especially those with a fever, tend to lose their appetites. When recovering from an infection, eating less is a natural response. However, until now, researchers still don't know whether fasting helps speed up healing or prolongs it.

Findings from a recent study could finally shed light on whether fasting is beneficial to an infected host. A team of scientists examined immunological responses in mice with and without fasting with surprising results: mice that were fasted for 24 hours before being exposed to salmonella were protected from infection. The researchers demonstrated that fasting interrupted infection and suppressed the bacteria's harmful effects in the gastrointestinal tract, preventing the pathogens from invading the inner lining of the gut. 

In addition, fasted mice had significantly lower levels of inflammation, demonstrating potential links between food intake and the immune system.

The researchers from the University of British Columbia also investigated whether fasting could enhance the effects of antibiotics during infection. Interestingly, they found that a course of antibiotics depleted the gut microbiota in fasted mice and did not have any observable impact on the activity of the antibiotics. 

Fasting also reduced the severity of infections when other types of bacteria were tested in the animal model.

Based on these results, does the conventional wisdom that sick patients should be encouraged to eat even if they don't feel like it still ring true? The verdict isn't out yet. While some studies support the hypothesis that not eating during an infection can be protective, others state the opposite. For example, a 2017 study suggests that reduced feeding intake can worsen conditions such as bacterial sepsis.

While fasting therapies such as intermittent fasting continue to gain popularity for treating chronic inflammatory diseases, more work needs to be done to understand how fasting influences an individual's susceptibility to infection.

Source: PLOS Pathogens.