Anthocyanin-Rich Freeze-Dried Berry Supplementation in Patients Undergoing Colorectal Cancer Treatment: A Prospective Single-Arm Pilot Study of Tolerability and Longitudinal Inflammatory Biomarker Changes

Background/Objectives: Anthocyanin-rich foods and supplements have shown anti-inflammatory activity in experimental studies, but clinical evidence in patients with colorectal cancer (CRC) remains limited. This exploratory pilot study evaluated longitudinal changes in systemic inflammatory biomarkers and the feasibility and tolerability of anthocyanin-rich berry supplementation during CRC treatment. Methods: In this prospective, open-label interventional study, 50 patients with CRC received an anthocyanin-rich freeze-dried whole-berry supplement (estimated anthocyanin intake of approximately 600–700 mg/day) for 21 consecutive days before initiation of oncological treatment and were followed for 12 weeks. Twenty non-cancer individuals served exclusively as a baseline comparator group. The comparator group was used only for baseline comparisons and not for longitudinal assessment of treatment effects. Clinical and laboratory assessments were performed at baseline, Week 4 (before initiation of oncological treatment), and Week 12 (during standard oncological treatment). Longitudinal changes in inflammatory and biochemical biomarkers were analyzed using non-parametric methods. Results: Median CRP concentrations decreased significantly during follow-up (n = 43), from 20.4 mg/L at baseline to 5.2 mg/L at Week 4 (following supplementation but before initiation of oncological treatment), and to 3.0 mg/L at Week 12 (during standard oncological treatment, p < 0.001). Significant longitudinal changes were also observed in interleukin-1α (IL-1α) net median fluorescence intensity (Net MFI), tumour necrosis factor-α (TNF-α) Net MFI, and interleukin-6 (IL-6) (n = 39). The supplement was generally well-tolerated among participants with available tolerability data (n = 47). Conclusions: A 21-day course of anthocyanin-rich berry supplementation was generally well-tolerated in patients with colorectal cancer. Longitudinal changes in systemic inflammatory biomarkers were observed during follow-up. Because the study did not include a longitudinal CRC control group and participants continued standard oncological treatment, these findings should be considered exploratory and cannot establish that the observed biomarker changes were caused by the supplementation. The observed biomarker patterns are hypothesis-generating and warrant confirmation in adequately powered controlled studies to determine whether anthocyanin-rich berry supplementation influences systemic inflammatory biomarkers in patients with CRC.