Q: I work as a nurse on the night shift.  I plan to do so until retirement, but I am also trying to do everything I can to stay healthy.

I use melatonin to sleep during the day.  I have trouble sleeping more than about three or four hours unless I take it.  Is this safe to continue?

A: There is a concern that shift workers may be at increased risk of developing breast cancer (Current Environmental Health Reports, September 2017).  People who work night shifts have their natural rhythm of melatonin production disrupted, and this may play a role in cancer susceptibility.  Spanish scientists have suggested that women like you possibly should take melatonin to offset this risk (Molecules, Feb. 6, 2018).  They point out, however, that there are not enough clinical trials to evaluate this approach properly.

A painstaking review of the literature concluded that melatonin may help with sleeping problems associated with shift work (Cochrane Database of Systematic Reviews, Aug. 12, 2014).  A study of emergency physicians working night shifts found that “Melatonin might have a limited benefit on sleep quality” (World Journal of Emergency Medicine, 2018, Vol. 9, No. 4).

• article by Joe and Teresa Graedon
• copyright The Seattle Times