Differences in skin health parameters and dietary associations based on gut enterotypes in healthy Korean adults

Gut enterotypes-dominated by Bacteroides (B-type) or Prevotella (P-type)-are closely associated with habitual dietary intake and our host health traits. However, differences in skin health and dietary associations according to enterotypes have not been fully elucidated. Therefore, we investigated these associations in 74 healthy Korean adults. Fecal microbiota composition, fecal SCFAs, fecal calprotectin, skin hydration and pH, skin free amino acids (FAAs), and dietary intake (via 3-day food records) were assessed. Two distinct enterotypes were identified: B-type (n = 48) and P-type (n = 26). The P-type exhibited higher α-diversity indices (Chao1, Shannon, inverse Simpson, and PD), greater carbohydrate and fiber intakes, and higher SCFA levels than the B-type. SCFA levels were positively associated with fiber intake and P-type-associated genera and were negatively associated with calprotectin levels. Skin hydration was also higher in the P-type and was positively correlated with α-diversity indices and P-type-associated genera, with stronger associations observed for the PD index. Furthermore, skin FAAs, which are critical for hydration, were positively correlated with skin hydration and negatively correlated with calprotectin levels. Latilactobacillus and Weissella, which are abundant in kimchi, were identified as key genera potentially involved in these processes. Finally, enterotype-dependent differences in dietary associations were observed: fiber and vitamin C intakes were significantly associated with improved skin hydration and/or pH only in the P-type. Collectively, our findings suggest that gut health status-characterized by bacterial diversity, SCFAs, and calprotectin, and represented by enterotypes-is closely associated with skin health and may modify the association between plant-based diets and skin health.