Authors:
Gorman S, Black LJ, Feelisch M, Hart PH, Weller R.
Authors notes:
Nutrients. 2015;7(5):3219-39.
Keywords:
sunlight, vitamin D, nitric oxide, liver, inflammation, non-alcoholic fatty liver disease
Abstract:
Liver inflammation contributes towards the pathology of non-alcoholic fatty liver disease (NAFLD).
Here we discuss how skin exposure to sunlight may suppress liver inflammation and the severity of NAFLD.
Following exposure to sunlight-derived ultraviolet radiation (UVR), the skin releases anti-inflammatory mediators such as vitamin D and nitric oxide.
Animal modeling studies suggest that exposure to UVR can prevent the development of NAFLD.
Association studies also support a negative link between circulating 25-hydroxyvitamin D and NAFLD incidence or severity.
Clinical trials are in their infancy and are yet to demonstrate a clear beneficial effect of vitamin D supplementation.
There are a number of potentially interdependent mechanisms whereby vitamin D could dampen liver inflammation, by inhibiting hepatocyte apoptosis and liver fibrosis, modulating the gut microbiome and through altered production and transport of bile acids.
While there has been a focus on vitamin D, other mediators induced by sun exposure, such as nitric oxide may also play important roles in curtailing liver inflammation.