While the phrase “burning the midnight oil” is familiar to many, the health problems associated with it may not be. With research linking the activity to cognitive impairment, metabolic disorders, and even breast cancer, working the night shift may negatively affect the body’s ability to repair its DNA.
Published in the journal Occupational & Environmental Medicine, Dr. Parveen Bhatti (of the Fred Hutchinson Cancer Research Center in Seattle, Washington) and colleagues explored the effects of working at night on the human body. They noted that sleeping during the day meant that a person had lower levels of 8-hydroxydeoxyguanosine — a chemical the body releases when it repairs DNA — while sleeping at night significantly increased this chemical.
But why does the body do this?
When a person works at night, their levels of melatonin drop. Dr. Bhatti and colleagues theorized that reduced melatonin levels among night-shift workers correlated to “decreased oxidative DNA damage repair capacity,” according to Medical News Today. To test their theory, Bhatti and colleagues selected a group of 50 shift-workers. Assessing their melatonin levels after a normal night’s sleep compared to when the shift workers had slept during the day, the findings were clear.
“Our results indicate that, relative to night sleep, reduced melatonin production among shift workers during night work is associated with significantly reduced urinary excretion of 8-OH-dG (this being a chemical released as a byproduct when the body is repairing DNA).” The researchers went on to explain that, “This likely reflects a reduced capacity to repair oxidative DNA damage due to insufficient levels of melatonin and may result in cells harboring higher levels of DNA damage.”
The researchers believe that if these effects are correct, giving night-shift workers melatonin supplements may be the key to helping reduce the occurrence of potentially carcinogenic DNA damage.