Eating at abnormal times disrupts the biological clock of the skin, including the daytime potency of an enzyme that protects against the sun’s harmful ultraviolet radiation, according to new research by the University of California.
This indicates that people who eat late at night may be more vulnerable to sunburn and skin cancer.
The study, which has been published in the journal Cell Reports, showed that mice given food during the day – an abnormal eating time for the otherwise nocturnal animals – sustained more skin damage when exposed to ultraviolet B light during the day than during the night.
This occurred because an enzyme that repairs UV-damaged skin became less active during the day. Mice fed only during the evening were less susceptible to daytime UV rays.
The study’s lead author, Dr. Joseph Takahashi (known for his landmark discovery of the Clock gene regulating circadian rhythms) said: ‘This finding is surprising. I did not think the skin was paying attention to when we are eating.’
‘It is likely that if you have a normal eating schedule, then you will be better protected from UV during the daytime. If you have an abnormal eating schedule, that could cause a harmful shift in your skin clock, like it did in the mouse.’
The researchers also discovered that a disrupted eating schedule can affect the expression of about 10 per cent of the skin’s genes
Previous studies have demonstrated strong roles for the body’s circadian rhythms in skin biology. However, little had been understood about what controls the skin’s daily clock.
The latest research published in Cell Reports documents the vital role of feeding times, a factor that scientists focused on because it had already been known to affect the daily cycles of metabolic organs such as the liver.
The study’s co-lead author, Bogi Andersen, says more research is needed to better understand the links between eating patterns and UV damage in humans: ‘It’s hard to translate these findings to humans at this point. But it’s fascinating to me that the skin would be sensitive to the timing of food intake.’