Improvement of skin condition and intestinal microbiota via Heyndrickxia coagulans SANK70258 intake: A placebo-controlled, randomized, double-blind, parallel-group comparative study

•We analyzed the effect of Heyndrickxia coagulans SANK70258 alone on skin and bowel conditions.•H. coagulans SANK70258 intake decreased fecal pH and phenol production.•Skin lightness, scaliness and liver function values improved with H. coagulans SANK70258 intake.•The fecal Nε-(carboxymethyl)lysine levels and plasma hydroxyproline concentrations decreased.•Improvement of the intestinal environment may partially enhance skin conditions. Heyndrickxia coagulans SANK70258, a representative probiotic, is known for alleviating inflammation caused by cedar pollen, improving the intestinal environment and bowel movements. A previous study on consuming H. coagulans SANK70258 together with galactooligosaccharides showed a trend toward improvement in skin scaliness scores and subjective assessments of skin roughness. However, the effect of H. coagulans SANK70258 alone on the skin remains unclear. Thus, we aimed to re-evaluate the effects of the intake of H. coagulans SANK70258 alone on skin conditions and the intestinal environment through a clinical trial. This placebo-controlled, double-blind clinical trial involved 80 Japanese women aged 30 to 65 with perceived skin roughness. Participants were divided into placebo and test groups. Over eight weeks, the test group consumed H. coagulans SANK70258, and its effects on skin condition and intestinal health were examined. The probiotic group showed significant intestinal improvements, with reduced fecal phenol levels (p = 0.044) and pH (p = 0.022), as well as enhanced skin lightness (L* value) (p = 0.040) and liver function tests. Metabolic analyses revealed decreases in fecal Nε-(carboxymethyl)lysine and plasma hydroxyproline, suggesting skin health benefits. There were also significant improvements in skin scaliness (p = 0.015) and bowel movement frequency (p = 0.032) in subgroup analysis. H. coagulans SANK70258 can improve skin health by improving the intestinal lining. This probiotic reduces the levels of intestinal putrefactive products and advanced glycation end-product levels in feces, suggesting that it may affect not only skin health but also systemic tissues such as the liver.