Working night shifts could impair immune system functionality and make people more susceptible to gut based infections, new research shows.

The Rhythm of the Night

The body runs like clockwork. When you eat, when you sleep and when you get up is all controlled by the body’s internal circadian rhythm aka the body clock. The body’s clock is based in the brain so it can respond to daylight levels, but it controls the clock inside every cell throughout the body to ensure they remain in sync. The main role of the body clock is to ensure we get sufficient sleep to maintain good health. Sleep deprivation has been linked to range of diseases, including gut inflammation disorders. To discover the reasons for this, scientists investigated how an out of sync body clock could impact the immune system.

Disrupting the Body Clock can Harm the Immune System

Type 3 innate lymphoid cells (ILC3s) are a type of immune cell based in the intestine. They play an integral role in maintaining gut health by fighting infection. ILC3s appeared to be particularly susceptible to body clock disruptions, which caused the number of ILC3 cells to substantially reduce. Therefore, the scientists suspected that ILC3s might be directly linked to the body clock in the brain.

In fact, disruption of the body’s clock disrupted the expression of genes in the IL3s that enabled them to migrate to the locations where they were needed to fight infection.

Out of Sync

Impaired Il3 function could therefore directly contribute to inflammatory intestinal diseases. Normally after eating, the body reduces the activity of the IL3s to enable effective digestion, but then re-activates the IL3s shortly afterwards to deal with any pathogens that may have been ingested with the food. However, if the body clock is out of sync than the brain could start activating IL3s when they are not needed, causing them to attack the gut wall and cause considerable inflammation.

As working the night shift causes the body clock to get out of sync, IL3 function could explain the link between poor sleep and increased likelihood to gut related illnesses. Companies should therefore consider the negative health implications of employees working night shifts and how they can look to reduce this adverse impact.