Food-seeking behavior is triggered by skin ultraviolet exposure in males

Abstract

Sexual dimorphisms are responsible for profound metabolic differences in health and behavior. Whether males and females react differently to environmental cues, such as solar ultraviolet (UV) exposure, is unknown. Here we show that solar exposure induces food-seeking behavior, food intake, and food-seeking behavior and food intake in men, but not in women, through epidemiological evidence of approximately 3,000 individuals throughout the year. In mice, UVB exposure leads to increased food-seeking behavior, food intake and weight gain, with a sexual dimorphism towards males. In both mice and human males, increased appetite is correlated with elevated levels of circulating ghrelin. Specifically, UVB irradiation leads to p53 transcriptional activation of ghrelin in skin adipocytes, while a conditional p53-knockout in mice abolishes UVB-induced ghrelin expression and food-seeking behavior. In females, estrogen interferes with the p53–chromatin interaction on the ghrelin promoter, thus blocking ghrelin and food-seeking behavior in response to UVB exposure. These results identify the skin as a major mediator of energy homeostasis and may lead to therapeutic opportunities for sex-based treatments of endocrine-related diseases.

The Complex Effects of Light on Metabolism in Humans

“…A recent epidemiology study reported that midday solar ultraviolet (UV) exposure (between 1100 h and 1300 h) increased food-seeking behavior and food intake in men but not in women. A similar finding of weight gain was observed solely in male mice [ 115 ]. These properties of light affecting peripheral regions of the body in a sex-dependent manner emphasize the importance of understanding the influence of light on individual organs.…”

The Impact of Ultraviolet Radiation on Energy Metabolism and Metabolic Disorders in Mice: Mechanisms and Implications

“…Allemann et al [41] reported that UVR (alone) did not significantly affect food intake and adiposity. However, Parikh et al [42] found that prolonged UVB exposure (50 mJ/cm 2 ) increased food-seeking behavior and food intake exclusively in mice and human men via p53-mediated ghrelin. This process is inhibited in females due to estrogen interfering with UV-induced p53.…”

Endogenous Photosensitizers in Human Skin

“…740,741 As already mentioned, there are several proven benefits: a bit of daily sun exposure increases lifespan substantially; 25 approximately 90% of all vitamin D used in our body is formed through the action of sun exposure; 26 a few minutes of sun exposure can lower the blood pressure for hours; 23 exposure to VL stimulates opsin that modulates the activity of cells from the subcutaneous white adipose tissue; 742 UV-B stimulates food-seeking behavior and food intake in men, but not in women. 743 The use of sun blockers avoids both the ancillary benefits of UV-B exposure and the erythema reaction, which is a natural protection mechanism that was selected during human evolution to avoid the consequences of an excess of sun exposure. 744 Switching off this signal allows people to endure longer times of sun exposure, with consequences that have not been properly investigated.…”

“…Unfortunately, besides the poor efficacy of protection there are intrinsic conceptual problems with the current sun protection guidance. First, the sun protection strategies contemplate mainly the bad consequences of an excess of sun exposure, imposing widespread and unrestricted use of sun blockers, without considering the benefits of small sun exposures. , As already mentioned, there are several proven benefits: a bit of daily sun exposure increases lifespan substantially; approximately 90% of all vitamin D used in our body is formed through the action of sun exposure; a few minutes of sun exposure can lower the blood pressure for hours; exposure to VL stimulates opsin that modulates the activity of cells from the subcutaneous white adipose tissue; UV-B stimulates food-seeking behavior and food intake in men, but not in women …”