Melatonin supplementation might help mitigate DNA damage in night-shift workers by enhancing the body’s repair mechanisms, according to a small clinical trial published online in Occupational & Environmental Medicine. Larger studies exploring different doses and long-term effects of melatonin are recommended by the researchers.
Night shift work disrupts normal production of melatonin, a hormone produced by the body clock that aids in repairing oxidative DNA damage resulting from cellular processes. This disruption increases cancer risk among night-shift workers, explain the researchers.
The study involved 40 night-shift workers who were randomly divided into two groups: one group took daily 3 mg melatonin pills with food and an hour before sleep during their day for four weeks; the other received a placebo pill under the same schedule. All participants worked at least two consecutive night shifts every week, lasting seven hours each, over six months without any sleep disorders or chronic conditions.
Urine samples were collected twice—once prior to starting the trial and another near its end—during periods of daytime sleep and subsequent night shift after a minimum of one day’s rest. Participants wore activity trackers for daily sleep monitoring.
The study measured 8-OHdG levels in urine, an indicator of DNA damage repair capacity. Among those taking melatonin supplements, urinary 8-OHdG was found to be 80% higher during daytime sleep compared to the placebo group, suggesting enhanced DNA repair capability. However, there were no significant differences in night-shift urinary 8-OHdG levels.
The researchers note that this is a small study with participants mainly from healthcare sectors; results may not apply universally. Natural light exposure was also unaccounted for, which affects melatonin production levels.
They acknowledge: “Oxidative DNA damage linked to reduced repair capacity is a plausible mechanism contributing to night shift-related cancer risk. Our randomized placebo-controlled trial indicated that melatonin supplementation might improve oxidative DNA damage repair among night-shift workers.”
The study concludes by emphasizing the need for larger-scale trials investigating different melatonin doses and long-term usage impacts. Pending such research, they suggest melatonin could be a viable strategy to reduce night shift-induced cancer risk.
They stress: “Evaluating long-term efficacy is crucial since prolonged nightly work requires consistent melatonin intake over many years to fully realize potential benefits in preventing cancers.”
