Targeting biological processes of aging is a central goal of geroscience; however, limited data exist regarding the feasibility of incorporating biological aging biomarkers into dietary intervention trials. We conducted a pilot feasibility study among 34 adults aged 48-81 years with metabolic syndrome, a condition associated with elevated risk of age-related cardiometabolic disease and advanced biological aging. Participants consumed 1 oz of tree nuts and two tablespoons of extra virgin olive oil daily for 4 weeks. The primary objectives were to evaluate feasibility, adherence, and participant acceptability of epigenetic aging assessments. Exploratory outcomes included DunedinPACE, a measure of the pace of aging, and AgeAccelGrim, a measure of biological age relative to chronological age. At baseline, all participants exhibited a faster pace of biological aging than average as assessed by DunedinPACE, supporting metabolic syndrome as a promising target population for geroscience interventions. Adherence to the dietary intervention exceeded 95%, and most participants reported willingness to participate in a similar longer-term trial. Participants expressed a strong interest in learning their biological age and indicated that evidence of slowed aging would motivate sustained dietary change. No significant changes in epigenetic aging were observed over the 4-week intervention. These findings demonstrate the feasibility and acceptability of incorporating epigenetic aging biomarkers into dietary intervention research and suggest that biological aging measures may serve not only as surrogate outcomes but also as tools to support participant engagement. The results also support metabolic syndrome as a relevant population for dietary geroscience trials and provide practical guidance for designing longer-term studies evaluating whether dietary interventions can slow biological aging and promote healthy longevity. ClinicalTrials.gov Identifier: NCT04361617 (date of registration: 04-23-2020).
