Plasmatic hippuric acid as a hallmark of frailty in an Italian cohort: the mediation effect of fruit-vegetable intake.

Frailty syndrome is an age-related condition involving a loss of resilience, susceptibility to adverse health outcomes and poor quality of life. This study was conducted in the framework of InveCe.Ab, an ongoing longitudinal population-based study. Plasma from 130 older individuals (older adults aged 76 to 78 years) was analysed and validated (on 303 subjects) using mass spectrometry-based metabolomics approaches. Equivalence tests showed that metabolites from the central cellular metabolic pathways were equivalent in Frail and Fit subjects. Hippuric acid was the only co-metabolite that distinguished Fit from Frail older adult. Logistic regression analysis indicated that high hippuric acid levels are significantly associated with a reduction of the risk of frailty after four years. Mediation analysis using a Frailty Index, hippuric acid and fruit-vegetable intake supported the role of fruit-vegetable consumption in the hippuric acid relationship with the Frailty Index. These data point to low plasma hippuric acid as a plausible hallmark of frailty status, associated with lower fruit-vegetable intakes.