Healthier and greener? Evaluating diet quality and sustainability indicators in Turkish adults

This study aimed to evaluate the associations between five diet quality indices (DQIs) and a comprehensive set of environmental sustainability indicators among Turkish adults. This cross-sectional study assessed dietary intake data from 514 adults (56.6% female, mean age 30.73 ± 11.80 years) using 24-hour dietary recalls. Diet quality was evaluated using Healthy Eating Index-2020 (HEI-2020), Mediterranean Diet Score (Med), Healthy Plant-Based Diet Index (hPDI), Planetary Health Diet Index (PHDI), and Dietary Approaches to Stop Hypertension Dietary Index (DASH). The carbon footprint (CF), water footprint (WF), land, fertilizer nutrients, and pesticide use were estimated using established databases. Female participants had significantly higher scores for HEI-2020 (p: 0.014), Med (p < 0.001), hPDI (p < 0.001), PHDI (p < 0.001), and DASH (p: 0.006) compared with males. Male participants had significantly higher daily CF, WF, land, fertilizer nutrient, and pesticide use compared with females (p < 0.05 for all). In multivariable energy-adjusted regression models, higher hPDI and PHDI scores were associated with reductions in three sustainability indicators each, whereas HEI-2020, Med, and DASH scores showed mixed associations across environmental outcomes. Higher DQIs were associated with lower environmental impacts; however, the strength and direction of these associations differed.