Study reveals melatonin supplements help repair DNA damage

For night shift workers, the biggest challenge is not just staying awake, but the real threat to long-term health. A recent study published in the journal Occupational & Environmental Medicine reveals that melatonin supplements can help the body repair DNA damage caused by working overnight. Melatonin is widely known as a sleep-regulating hormone that naturally increases in darkness. However, for those working at night, this natural rhythm is disrupted. Reduced melatonin production weakens the body’s ability to repair oxidative DNA damage, a form of cellular wear caused by normal metabolism. The reduced DNA repair capacity is suspected to be one pathway leading to higher risks of certain cancers among night shift workers. The International Agency for Research on Cancer (IARC) has even classified night shift work as probably carcinogenic to humans due to disruptions in the body’s biological clock. To test melatonin’s potential, researchers conducted a placebo-controlled randomised clinical trial involving 40 healthy night shift workers (mostly healthcare professionals) who had worked nights at least twice a week for at least six months. Half the participants took a 3mg melatonin pill once daily for four weeks, consumed with food one hour before their daytime sleep. The other half took a placebo pill on the same schedule. Researchers measured 8-OHdG levels in urine, an indicator of oxidative DNA damage repair capacity. The results showed that those taking melatonin had 80% higher 8-OHdG levels during daytime sleep compared to the placebo group. This indicates melatonin successfully boosted DNA repair activity while they slept during the day after night shifts. However, similar effects were not observed during the subsequent night shift. Although the findings offer a promising mechanistic explanation for melatonin’s role in restoring disrupted biological clocks, researchers stressed the study was small-scale and short-term, and did not directly measure cancer outcomes. The researchers emphasised their findings need to be retested with larger-scale studies and longer monitoring periods. ‘Increased oxidative DNA damage due to reduced repair capacity is a strong mechanism contributing to the carcinogenicity of night shift work. Our placebo-controlled randomised clinical trial showed melatonin supplementation can enhance the capacity to repair oxidative DNA damage among night shift workers,’ the researchers wrote. They concluded that further studies are needed to confirm the long-term viability of this intervention. ‘Our findings require larger future studies examining varying melatonin doses and long-term usage effects. Until then, melatonin supplementation may prove a viable intervention strategy to reduce cancer burden among night shift workers,’ they added. ‘Assessing long-term efficacy is crucial, as those working nights for years need consistent melatonin supplementation over that period to maximise potential cancer prevention benefits,’ the research team added. For now, the study offers hope that melatonin serves a greater purpose than just aiding sleep—activating vital cell repair processes during daytime rest. (Science Daily/Z-2)