The skin’s epidermis is relatively thin, and functions chiefly as a protective barrier, while the thicker dermis comprises the bulk of skin and carries its nerves, blood vessels, sensory apparati, and hair follicles. The epidermis and dermis contain distinctive populations of immune cells from innate and adaptive immune system compartments, and respond to environmental challenges in different ways.
Skin irritation from various causes has been linked to altered skin levels of omega-3 fatty acid metabolites, including pro-resolving mediators (resolvins, protectins, maresins, and others), endocannabinoid-like lipids, and other eicosanoids. These skin changes are often accompanied by shifts in the balance among immune cell populations that mediate the skin’s inflammatory response, including resident and infiltrating (migrating) cell types.
For this open-label clinical trial, 21 adults aged 18-60 years were given omega-3 fatty acid supplements providing a daily dose of either 3.5 g EPA + 0.5 g DHA or 3.5 g DHA + 0.5 g EPA for a 10-week period. Prior to and after the supplementation period, subjects were exposed to UV light sufficient to induce reddening on a limited area of previously unexposed skin. Blood and skin biopsy samples were taken from UV-treated and untreated skin for evaluation of baseline and post-intervention values of selected plasma, dermal, and epidermal lipids, enzymes, and immune cell populations. After UV exposure, skin biopsies were taken at 24- and 72-hour time points.
EPA and DHA Affect Skin Immune Response Differently
Supplementation with EPA and DHA may be of benefit in skin affected by altered lipid mediators and/or immune cell imbalance due to a variety of causes. In this study, generous supplementation with mainly-EPA or mainly-DHA formulations each improved the skin’s response to UV light exposure in a distinct manner.