Association between the Planetary Health Diet Index and growth differentiation factor-15: the Seniors ENRICA-2 cohort

The growth differentiation factor-15 (GDF-15) is an inflammaging biomarker, predictor of cardiovascular disease (CVD), and several other non-communicable diseases (NCD) that represent the main causes of death globally, for which prevention is essential. Current worldwide threats include NCD and environmental burden, where diet is a key determinant. Therefore, the EAT-Lancet Commission developed the Planetary Health Diet Index (PHDI), a dietary pattern designed to ameliorate human and environmental health. The objective of the study was to evaluate the association between the PHDI and serum concentrations of GDF-15 in older adults. Study participants were 2497 people aged + 65 years from the Seniors-ENRICA-2 study. Food consumption was obtained through a validated diet history, and adherence to the PHDI was estimated with a score of 15 food groups (range 0-140), where higher scores indicated better adherence. Analyses for the association between the PHDI and GDF-15 concentrations were performed using multivariable linear regression models, adjusting for main potential confounders. The PHDI showed an inverse dose-response association with GDF-15 concentrations. Compared with participants in the lowest quartile of the PHDI, those in the highest quartile had a mean percentage difference (95% CI) of - 6.8% (- 11.1, - 2.4) in GDF-15 concentrations. The mean percentage difference (95% CI) per 20-point increase of adherence was - 4.4% (- 7.7, - 0.9). Consumption of whole grains, fruits, nuts, and a low intake of trans and saturated fat were important drivers of this association. Results remained robust after adjustment for other inflammation (interleukin 6), renal and cardiac (creatinine, NT-proBNP, cardiac troponin T) biomarkers, and after excluding participants with CVD, type 2 diabetes, and obesity. The PHDI was associated with lower concentrations of GDF-15. Adopting the PHDI may be a useful approach to reduce chronic inflammation and target NCD prevention in the older adult population, while staying within planetary boundaries.