A Novel Diet-Health Index Reveals Worsening Trends and Widening Disparities in the Health Impacts of Diet in the United States

Abstract Objectives Poor diets are associated with poor health outcomes, but existing metrics of diet quality do not directly include the health effects of diet. Using a novel international diet-health index (IDHI), we can measure diet-related health impacts from multiple dietary factors simultaneously, given a population's health status and most prevalent causes of death and disability. Methods We obtained individual-level data on intake of 12 dietary factors and exposure to 2 metabolic risk factors from the National Health and Nutrition Examination Survey (NHANES), 2003–2014, and computed the IDHI for 12 cardio-metabolic diseases and 15 cancers in the U.S. by sex, race, education, and income. We then compared IDHI to a modified Alternative Healthy Eating Index (mAHEI) using 10 of the 12 dietary factors and validated the indices using the National Center for Health Statistics (NCHS) linked dataset for total mortality through 2015. Results IDHI declined from −0.314 (95% CI: −0.323, −0.305) in 2003/04 to −0.325 (−0.334, −0.316) in 2013/14 (P = 0.007 for trend). Non-Hispanic Black Americans have persistently lower IDHI than other groups, and disparities in IDHI have widened over time by level of income (P = 0.004 for interaction), and education (P = 0.047 for interaction). IDHI was more closely correlated with the mAHEI at higher levels of diet quality, and both indices were strongly associated with total mortality. Conclusions The IDHI is a valid tool for measuring diet-related health impacts in the context of a population's most prevalent diseases, potentially offering tailored guidance regarding how best to reduce diet-related health disparities. Funding Sources No funding.