Higher dietary vegetable and fruit intake along with their biomarkers is inversely associated with all-cause mortality among cancer survivors

The association between dietary vegetable and fruit (VF) intake and survival outcomes among cancer survivors remains unclear, with limited research available on the association between VF-related biomarkers and mortality in this population. We hypothesized that there were inverse relationships between dietary VF intake, serum carotenoids, serum vitamin C, composite biomarker score and both all-cause and cancer-specific mortality among cancer survivors. This study analyzed cancer survivors from the National Health and Nutrition Examination Survey (NHANES) 1999 to 2018 cycles for VF intake (n = 4326), and from NHANES III, 2003 to 2006, and 2017 to 2018 cycles for serum carotenoids (n = 2187), serum vitamin C (n = 2267), and composite biomarker score (n = 2131). Weighted multivariable Cox proportional hazards regression models were used to assess the associations between exposures and mortality, computing hazard ratio (HR) and 95% CI. Dietary VF intake was significantly associated with a lower risk of all-cause mortality (HR = 0.80, 95% CI: 0.67−0.96) over a median follow-up of 6.9 years. For serum biomarkers, higher concentration of total carotenoids (median follow-up: 10.0 years), vitamin C (median follow-up: 9.4 years) and higher composite biomarker score (median follow-up: 10.1 years) were associated with lower risks of all-cause mortality, with HRs (95% CIs) of 0.73 (0.58−0.92), 0.73 (0.56−0.95), and 0.73 (0.57−0.95), respectively. Additionally, only vitamin C was linked to cancer-specific mortality, with HRs (95% CIs) of 0.55 (0.37−0.81). Higher VF intake and their associated biomarkers are associated with a lower risk of all-cause mortality among U.S. cancer survivors.