Ultra-processed food intake and inflammatory markers in breast cancer survivors

Objectives: This study aimed to examine the associations between ultra-processed food intake and inflammatory markers among Korean breast cancer survivors. Methods: A total of 641 breast cancer survivors were included. Ultra-processed food intake was assessed using 3-day dietary records or a validated food frequency questionnaire. Plasma levels of high-sensitivity C-reactive protein (hs-CRP), interleukin-6, interleukin-8, tumor necrosis factor-alpha, and adiponectin were measured. A composite inflammatory z-score was calculated from these five biomarkers. Multivariate logistic regression and general linear models were used to estimate odds ratios (ORs) and least-squares (LS) means for inflammatory markers. Results: Total ultra-processed food intake was not associated with inflammatory markers overall. However, the associations varied by menopausal status at diagnosis, estrogen/progesterone receptor (ER/PR) subtype, and age. Comparing extreme quartiles of ultra-processed food intake, ORs (95% confidence intervals, CIs) for an increased composite inflammatory z-score were 0.57 (0.28, 1.19) and 3.10 (1.20, 8.00) among participants who were premenopausal and postmenopausal at diagnosis, respectively ( p for interaction < 0.01). LS means (95% CIs) for hs-CRP (mg/L) in the lowest and highest quartiles of ultra-processed food intake were 0.28 (0.16, 0.51) and 0.59 (0.33, 1.06) among those with ER/PR-negative tumors ( p for trend = 0.03), whereas the corresponding values were 0.41 (0.31, 0.53) and 0.48 (0.37, 0.61) among those with other subtypes ( p for trend = 0.67); the interaction did not reach statistical significance ( p for interaction = 0.26). For reduced adiponectin, ORs (95% CIs) comparing extreme quartiles of ultra-processed food intake were 0.57 (0.26, 1.26) in those aged < 50 years and 2.65 (1.20, 5.88) in those aged ≥ 50 years ( p for interaction = 0.03). When we examined the associations of ultra-processed food subgroups, higher intake of packaged and instant noodles was associated with increased hs-CRP. Conclusions: Higher ultra-processed food intake was associated with unfavorable inflammatory profiles among Korean breast cancer survivors who were postmenopausal at diagnosis, ER/PR-negative, or aged 50 years and older. Among ultra-processed food subgroups, greater intake of packaged and instant noodles was associated with higher hs-CRP. Acknowledgements: This research was supported by the National Research Foundation of Korea grants, funded by the Ministry of Science and ICT (2014R1A2A2A01007794, 2019R1F1A1061017, 2021R1F1A1062476, and RS-2025-00560416).