Modulating the skin microbiota with oral solutions

In numerous murine models, a Lactobacillus-enriched diet reduces skin sensitivity, rash, inflammation, dermatitis, etc., and improves skin phenotype (increased dermal thickness, enhanced folliculogenesis and increased sebocyte production).²³ These beneficial probiotic effects have been confirmed by several interventional studies in humans involving lactobacilli and/or bifidobacteria.²³ Managing skin diseases by modulating the gut microbiota will most likely involve probiotics (beneficial live bacteria), prebiotics (bacterial substrates) and symbiotics (combinations of pro- and prebiotics).²³

A lack of adverse effects makes oral probiotics of even greater interest for the management of skin diseases.¹⁴

For example, in atopic dermatitis, daily consumption of probiotics (Bifidobacterium) and prebiotics (galacto-oligosaccharides) improves skin hydration in healthy adult women.¹⁴ To take another example, oral Lactobacillus supplementation reduces skin sensitivity and strengthens the skin’s barrier function in adults²⁹ and children³⁰. Several clinical trials have shown probiotics to have a positive effect when taken alone or in a cocktail (lactobacilli, bifidobacteria and/or S. thermophilus), with a reduction in lesions and severity in the case of acne.^12,23 The positive effects of oral probiotics may be due to their ability to reduce systemic oxidative stress, regulate cytokines and reduce inflammatory markers.⁹ In the case of psoriasis, there are still few clinical data, but two studies in humans show beneficial effects: a reduction in inflammation markers with B. infantis; a reduction in the severity and appearance of lesions with B. longum, B. lactis and L. rhamnosus alongside a topical corticosteroid treatment.¹³ There were similar results for seborrheic dermatitis, with inflammation and symptoms relieved by oral L. paracasei.¹² Some probiotics may even protect against skin cancer.¹⁶ However, clinical trials are still required to identify the most effective formulation of probiotic strains, the optimal duration of supplementation and the patients most likely to benefit.¹⁴