Night shift workers face an increased risk of cancer, as their disrupted sleep cycle causes wear and tear on their DNA.

But taking melatonin might help ward off this risk, a new study suggests.

Folks on the night shift taking melatonin had a substantial increase in their urine of a biochemical that indicated better DNA repair while they sleep, researchers reported Feb. 24 in the journal Occupational & Environmental Medicine.

“Melatonin supplementation may prove to be a viable intervention strategy to reduce the burden of cancer among night shift workers,” concluded the research team led by Dr. Parveen Bhatti, a distinguished scientist with the BC Cancer Research Institute at the University of British Columbia in Canada.

People who work night shifts typically have lower levels of melatonin, a hormone that helps synchronize sleep/wake cycles. Melatonin is produced in response to a person’s exposure to sunlight.

This compromises the body’s ability to repair DNA damage that occurs as part of daily life, increasing their risk of cancer, researchers said.

To see if boosting a person’s melatonin might offset this damage, researchers recruited 40 night shift workers and randomly assigned half of them to take a 3 mg melatonin pill at bedtime every day for four weeks. The other half took a placebo pill.

All the participants worked at least two consecutive night shifts every week, lasting at least seven hours a night for at least six months, researchers said.

Researchers then compared urine samples taken at the start and end of the four-week trial to check participants’ levels of 8-hydroxy-2′-deoxyguanosine (8-OH-dG), a chemical produced when cells repair DNA damage.

Higher levels of 8-OH-dG indicate that the body is doing a better job repairing damaged DNA, researchers added.

Results showed that people taking melatonin had 80% more 8-OH-dG in their urine following daytime sleep.

Melatonin has been shown to promote genetic pathways that are involved in DNA repair, researchers said. Low levels of melatonin might affect the body’s ability to recognize and repair damaged DNA.

These results warrant further studies in longer-term trials involving more people, researchers concluded.

“Assessing long-term efficacy is critical since those who work night shifts for many years would need to consistently consume melatonin supplements over that time frame to maximize the potential cancer prevention benefits,” researchers concluded.

More information 

The University of California-Davis has more on melatonin and sleep.

SOURCE: BMJ, news release, Feb. 24, 2025

Source: HealthDay

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