Bifidobacterium Mediates the Associations Between the Dietary Approaches to Stop Hypertension (DASH) Diet and Blood Pressure and Blood Lipids in Chinese Adults

Background: The Dietary Approaches to Stop Hypertension (DASH) diet effectively lowers blood pressure and improves blood lipid profiles. However, it remains unclear how the DASH diet contributes to gut microbiota and how the gut microbes affect these processes. This study aimed to examine the associations of DASH diet adherence with blood pressure and lipid levels, and to explore whether the gut microbiota mediated these relationships. Methods: A total of 879 Chinese aged over 18 years were recruited. DASH diet adherence was evaluated by a food frequency questionnaire. Blood pressure and lipid measurements were obtained during physical examinations. The gut microbiota was analysed via 16S rRNA sequencing. Results: Greater DASH diet adherence was correlated with lower diastolic blood pressure (DBP; sβ = −0.180 and p = 0.027) and low-density lipoprotein cholesterol (LDL-C; sβ = −0.268 and p = 0.002). Five bacterial genera were associated with the DASH diet (q-value < 0.15). Among them, Bifidobacterium was inversely linked to both DBP and LDL-C (p < 0.050). Two species (Bifidobacterium kashiwanohense and Bifidobacterium longum) were detected within the Bifidobacterium genus. Both of them explained the associations of the DASH diet with DBP and/or LDL-C (average causal mediation effect = −0.027 to −0.018; p < 0.050; proportion mediated = 8.22% to 9.04%). Conclusions: This study found favourable correlations of the DASH diet with both DBP and LDL-C. Bifidobacterium partially explained these relationships. These results may offer valuable insights into managing blood pressure and lipid levels through dietary and gut microbiota modulation.