Late-Night Eating Could Increase Sunburn Risk

Abnormal eating times shown to increase susceptibility to daytime ultraviolet rays.

Findings from a new study published by Cell Reports indicate that eating at abnormal times may disrupt the skin’s protection against the sun’s ultraviolet (UV) rays. The authors suggest that sunbathers should avoid late-night snacking to prevent adverse events.

The mouse study indicated that eating at abnormal times can disrupt the circadian rhythm of the skin, including the efficacy of an enzyme that protects the skin against daytime UV rays.

While further research is needed, the authors hypothesize that individuals who eat late at night may have a higher risk of sunburn, skin aging, and skin cancer.

“This finding is surprising. I did not think the skin was paying attention to when we are eating,” said researcher Joseph S. Takahashi, PhD.

In the study, the mice were only given food during the day, which is an abnormal time for nocturnal animals. The authors found that these mice experienced more skin damage when exposed to ultraviolet B (UVB) light during the day compared with at night.

These results occurred due to the xeroderma pigmentosum group A (XPA) enzyme, which repairs UV-damaged skin. This enzyme experienced a shift to become less active during the day, according to the study.

Mice who were fed during normal times did not have a shift in XPA and were less susceptible to UVB rays during the day, the authors reported.

“It is likely that if you have a normal eating schedule, then you will be better protected from UV during the daytime,” Dr Takahashi said. “If you have an abnormal eating schedule, that could cause a harmful shift in your skin clock, like it did in the mouse.”

Previous studies have shown that the body’s circadian rhythm is important for the skin, but what controls the biological clock has not been understood.

The new study reinforces the critical role of feeding times, which has already been known to impact the cycle of metabolic organs, such as the liver.

The authors also found that changing eating times could result in altered expression of 10% of the skin’s genes, according to the study.

The authors note that further research is necessary to better understand how eating patterns can lead to UV damage in humans, especially related to XPA.

The investigators are currently conducting a long-term study to determine how feeding patterns can affect aging and longevity.

“It’s hard to translate these findings to humans at this point,” said researcher Bogi Andersen, MD. “But it’s fascinating to me that the skin would be sensitive to the timing of food intake.”