(OR25-02-26) Associations of Multiple Dietary Indices With Health Outcomes and Diet‑Related Greenhouse Gas Emissions in U.S. Adults: Evidence From NHANES 2005–2018

Objectives: This study aimed to examine associations of multiple dietary indices with major chronic diseases (MCDs) (including cancer, diabetes, and cardiovascular diseases), all-cause mortality, and dietary-related greenhouse gas emissions (GHGE) among United States adults.

Methods: We analysed data from 27,517 US adults who participated in the National Health and Nutrition Examination Survey (NHANES) 2005–2018 and provided their disease information and two-day 24-hour diet recalls. Seven dietary patterns, including the Healthy Eating Index-2020 (HEI-2020), Alternate Healthy Eating Index (AHEI), Dietary Approaches to Stop Hypertension (DASH), alternate Mediterranean Diet score (aMED), Planetary Health Diet Index (PHDI), American Cancer Society 2020 diet score (ACS2020), and the Dietary Index for Gut Microbiota (DI-GM), were assessed. Dietary-related GHGE were estimated by linking individual food intakes to dataFRIENDS, a food environmental impact database. All-cause mortality was obtained by linkage to the National Centre for Health Statistics mortality files up to 2019.

Results: For MCDs, compared with those in the lowest quintile, participants in the highest quintile of HEI-2020, AHEI, DASH, aMED, and ACS2020 were significantly associated with 12-15% lower prevalence of MCDs. For all-cause mortality, all studied diet patterns showed strong inverse associations with risk of death, especially PHDI and DI-GM (about 48% lower risk of death in Q5 vs Q1). For environmental impact, higher dietary scores were associated with lower diet-related GHGE, especially the PHDI, DI-GM, and ASC2020 (1.30, 1.40 and 1.84 kgCO2e/ day lower in Q5 vs Q1, respectively).

Conclusions: Overall, higher adherence to healthy dietary patterns was associated not only with better health outcomes but also lower diet-related GHG emissions, supporting co-benefits for human health and environmental sustainability.

Funding Sources: The study is funded by Seeds grant at College of Health Sciences, Vin University.