Pro-Inflammatory Diet Accelerates Sarcopenia in Older Polish Adults

Sarcopenia—the progressive loss of skeletal muscle mass, strength, and function—affects roughly 18.6% of older Polish adults and dramatically shortens survival. Chronic low-grade inflammation driven by poor diet and physical inactivity is increasingly recognized as a key driver of this condition, yet few studies have quantified dietary inflammatory potential alongside both physical performance metrics and a broad panel of inflammatory biomarkers in the same cohort.

This prospective study enrolled 121 community-dwelling adults aged 60–96 from a University of the Third Age program in Poland. Participants were categorized as sarcopenic (n=38), probably sarcopenic (n=38), or non-sarcopenic (n=45) according to the EWGSOP2 clinical algorithm, which incorporates handgrip strength, appendicular skeletal muscle mass index (ASMI), and physical performance via the 6-minute walk test (6MWT). Dietary intake was assessed through two 24-hour dietary recalls (one weekday, one weekend day), and the Energy-adjusted Dietary Inflammatory Index (E-DII) was calculated per 1,000 kcal to correct for total energy intake. Blood biomarkers included IL-1β, IL-6, TNFα, CRP, albumin, and cell-free DNA (cfDNA).

The optimal E-DII cut-off for sarcopenia risk was 2.283, yielding an AUC of 0.734, sensitivity of 70.6%, and specificity of 75.6% (p<0.001). Sarcopenic individuals had significantly higher E-DII scores than non-sarcopenic peers, indicating more pro-inflammatory dietary patterns. Critically, E-DII correlated inversely with gait speed (rs = −0.502, p=0.001) and 6MWT distance (rs = −0.496, p=0.001), linking diet quality directly to functional decline. When E-DII was combined with cfDNA in a diagnostic model, AUC improved to 0.805 with 79.7% classifier accuracy—outperforming models using conventional cytokines (IL-1β, IL-6, TNFα), which achieved acceptable but lower discrimination (AUC 0.7–0.8). CRP and albumin ratio also showed utility as accessible inflammatory markers.

The study highlights cfDNA as a particularly promising emerging biomarker: cellular damage from chronic inflammation releases cfDNA into circulation proportionally to inflammation severity, and its combination with dietary inflammatory scoring provides a novel, higher-accuracy sarcopenia prediction tool. This is among the first studies to directly connect E-DII with cfDNA levels in any population.

Caveats include the cross-sectional dietary assessment relying on a single-day recall per occasion, limiting precision; the predominantly female sample (91 of 121 participants) reduces generalizability to men; and the study's observational design precludes causal inference. Despite these limitations, the results support dietary intervention—specifically shifting toward anti-inflammatory eating patterns—as a plausible strategy to slow sarcopenia progression in aging populations.