Dietary (poly)phenol intake and risk of short telomeres in older adults: A prospective analysis

Background & Aims Telomere shortening is a hallmark of biological ageing and may be accelerated by oxidative stress and inflammation. Dietary (poly)phenols, a group of bioactive compounds widely distributed in plant-based foods, may contribute to telomere maintenance through antioxidant and anti-inflammatory mechanisms. However, prospective evidence on the association between habitual dietary (poly)phenol intake and telomere length remains limited. The aim is to assess the longitudinal association between dietary (poly)phenol intake and the risk of short telomeres in Spanish adults aged ≥55 years from the Seguimiento Universidad de Navarra (SUN) Project. Material & Methods This prospective analysis included 1,665 participants from the SUN cohort with available dietary data and telomere length (TL) measurements. Dietary intake was assessed at baseline using a validated 136-item semi-quantitative food-frequency questionnaire. Energy-adjusted total and class-specific dietary (poly)phenol intake were estimated using the Phenol-Explorer database. TL was measured in saliva samples using monochrome multiplex quantitative PCR and expressed as the telomere-to-single-copy gene (T/S) ratio. Short telomeres were defined as TL below the 20th percentile, calculated separately within each sample collection wave to account for batch effects. Multivariable logistic regression models were used to estimate odds ratios and 95% confidence intervals for short telomeres, adjusting for sociodemographic, lifestyle, dietary, and clinical covariates. Results Higher flavonoid and total (poly)phenol intake were associated with a lower risk of short telomeres. In the fully adjusted model, participants in the highest versus lowest extreme decile of flavonoid and total (poly)phenol intake had approximately 49% (OR: 0.51; p = 0.032) and 43% (OR: 0.57; p = 0.084) lower risk of short telomeres, respectively. Exploratory age-stratified analyses showed that each 1-SD increment in total (poly)phenol intake was associated with a lower risk of short telomeres among participants younger than 64 years (OR: 0.78; p = 0.029), but not among those aged ≥64 years (OR: 1.01; p = 0.870); however, effect modification by age was not statistically significant (p for interaction=0.070). Among the main (poly)phenol-contributing foods, coffee consumption (up to one cup/day vs. none; OR: 0.70; p = 0.019) and high fruit intake (Q4 vs. Q1; OR: 0.65; p = 0.020; p for trend=0.024) were associated with a lower risk of short telomeres. Conclusions Higher flavonoid and total (poly)phenol intake were associated with a lower risk of short telomeres. Among the main dietary contributors, coffee and fruit intake were also inversely associated with the risk of short telomeres. These findings suggest that a (poly)phenol-rich dietary pattern may be related to healthier cellular ageing. Further studies incorporating repeated TL measurements, objective biomarkers of (poly)phenol exposure, and intervention designs are needed to confirm these findings and clarify the underlying mechanisms.