Dietary antioxidant index and cardiometabolic risks in normal-weight individuals: Evidence from the National Health and Nutrition Examination Survey.

BACKGROUND AND OBJECTIVES: Caloric restriction is the most popular dietary intervention for preventing metabolic disorders. However, its benefits are limited in normal-weight individuals. This study aimed to examine the association between composite dietary antioxidant index (CDAI) and metabolically unhealthy normal weight (MUNW), as well as the relationship between CDAI and cardiometabolic mortality among normal-weight individuals, in order to provide personalized dietary recommendations. METHODS AND STUDY DESIGN: This study consisted of two parts: (1) a cross-sectional analysis exploring the association between CADI and MUNW; and (2) a prospective cohort analysis assessing CDAI in relation to cardiometabolic mortality. Adult participants with normal weight from the National Health and Nutrition Examination Survey (2007-2018) were enrolled and classified into quartile groups based on CDAI for the analyses. RESULTS: Among 4,590 participants included in this study, 472(7.82%) were diagnosed with MUNW. After full adjustment, the odds ra-tios (95% confidence intervals) for MUNW across the increasing CDAI levels were 0.80 (0.50-1.29), 0.85 (0.51-1.41), and 0.48 (0.26-0.87), respectively (p for trend = 0.026). This inverse association appeared to be attenuated among participants aged 20~59 years old (p for interaction = 0.035). During 32,113 person-years of follow-up, 82 cardiometabolic deaths occurred. After full adjustment, the hazard ratios (95% confidence intervals) for cardiometabolic mortality across the increasing CDAI levels were 0.78 (0.35-1.73), 0.51 (0.20-1.27), and 0.40 (0.19-0.87), respectively (p for trend = 0.014). CONCLUSIONS: CDAI was inversely associated with MUNW and cardiometabolic mortality in a normal-weight population in the United States. These findings warrant confirmation through interventional studies.