Probiotics, Prebiotics, and Synbiotics as Oral Supplements for Skin Health, Function, and Disease Throughout the Life Course: A Scoping Review.

In this review we sought to map the body of published literature on the role of oral probiotics, prebiotics, and synbiotics in maintaining and optimizing skin health and function and preventing and managing skin conditions throughout the life course. Globally, the burden of skin diseases is considerable. Diet is a modifiable risk factor for many dermatological conditions, and one mechanism by which nutrition influences skin health is through the gut microbiome. Oral probiotics, prebiotics, and synbiotics have the potential to improve skin health, delay skin aging, and successfully treat dermatological diseases. We developed a scoping review protocol in accordance with the Johanna Briggs Institute methodology. Six online databases were systematically searched for peer-reviewed literature, and non-peer-reviewed sources were also considered. All records were screened independently by 2 reviewers using predefined eligibility criteria. A total of 516 studies were included in the scoping review, comprising 73 systematic reviews. Most studies investigated probiotics (n = 401). Infants (0-12 months old) and adults (18-60 years old) were the age groups most frequently receiving supplementation with probiotics (42% [n = 114] and 41% [n = 112] of human studies, respectively), whereas only 15% of studies (n = 41) comprised adults participants older than 60 years. Of the skin diseases investigated, atopic dermatitis was the most extensively researched (n = 330 studies), followed by psoriasis (n = 24), and acne (n = 23). Skin health and function in healthy populations is a growing area of research; outcomes related to wrinkling, elasticity, aging, or UV irradiation response accounted for 54 studies. Consistencies in the evidence base found in our investigation underscore the need for an umbrella review on oral probiotics, prebiotics, and synbiotics and atopic dermatitis, as well as a systematic review on skin aging. Preliminary evidence for roles in managing rosacea, alopecia, and melasma suggests additional research avenues. Future studies should consider participant diets, probiotic strain and dose reporting, and inclusivity of populations and languages.