Association between high dietary intake of live microbes from food and all-cause and cause-specific mortality in cancer patients: A prospective cohort study

Dietary live microbes have gained attention as potential modulators in chronic disease management, yet their impact on the survival of cancer patients remains underexplored. This study assessed the association between dietary live microbe intake from food and all-cause as well as cause-specific mortality in cancer patients. Data from 3649 adult cancer patients in the 1999 to 2018 National Health and Nutrition Examination Survey were analyzed. Participants were grouped according to their intake of foods with medium-to-high microbial content (MedHi food): G1 (no intake), G2 (below median), and G3 (above median). Kaplan–Meier survival analysis and multivariable Cox regression were used to evaluate mortality outcomes, while restricted cubic spline models assessed dose–response relationships. Over a median follow-up of 7.08 years, 1290 participants died, including 424 cancer-specific deaths. Compared with G1, G3 had 21% lower all-cause mortality and 27% lower noncancer mortality. No significant association was observed with cancer-specific mortality. A nonlinear, inverse relationship was observed for all-cause mortality at intake levels below 489.7 grams, plateauing beyond this threshold. Higher MedHi food intake was associated with lower risks of all-cause and noncancer mortality among adults with self-reported cancer, but not with cancer-specific mortality. Because National Health and Nutrition Examination Survey lacks detailed information on cancer type, stage, treatment, and time since diagnosis, these cancer-specific clinical factors were not adjusted for in the present analyses. These findings should therefore be interpreted as observational and hypothesis-generating, and may inform future prospective studies on dietary live microbes and survival among cancer survivors.