This observational study aimed to investigate associations between dietary live microbe intake and mortality, as well as biological aging. Adults from the 1999-2018 National Health and Nutrition Examination Survey were categorized into low, medium, and high dietary live microbe groups. Foods with medium and high live microbe content were aggregated into a medium-high consumption category. The outcomes included all-cause, cardiovascular, and cancer mortality, along with biological age (BA) acceleration assessed by the Klemera-Doubal method (KDM) and PhenoAge. Multiple regression analyses and mediation analyses were conducted to assess associations, adjusting for potential confounders. A total of 34 133 adults were included in our analyses. Over an average follow-up period of 9.92 years, 5 462 deaths occurred. In multivariate adjusted models, every 100 g of medium-high group foods consumed was associated with reduced all-cause mortality (hazard ratio [HR] 0.94, 95% confidence interval [CI] 0.91 to 0.97, p < .001) and cardiovascular mortality (HR 0.91, 95% CI 0.86 to 0.96, p < .001), but not with cancer mortality (HR 1.01, 95% CI 0.95 to 1.07, p = .768). Every 100 g medium-high group foods consumption was associated with decreased KDM-BA acceleration (fully adjusted regression coefficient -0.09, 95% CI -0.15 to -0.04, p = .001) and PhenoAge acceleration (fully adjusted regression coefficient -0.07, 95% CI -0.11 to -0.03, p < .001). Mediation analysis showed that BA acceleration partially mediated live microbes-mortality associations. Our results suggest that higher dietary live microbe intake is associated with lower mortality risk and slower biological aging. However, further research is needed to verify these findings.
