Abstract
Chronic inflammation is one of the causes of colorectal cancer (CRC), and circulating levels of inflammatory biomarkers have been linked to tumor promotion and progression. We aimed to evaluate the interleukin-6 (IL-6) level in CRC patients and determine whether a diet rich in antioxidants was associated with CRC. This study included 654 cases and 1312 controls matched for age and sex. We measured the plasma IL-6 concentration and estimated dietary antioxidant capacity based on oxygen radical absorbance capacity (ORAC) combined with a 106-item semiquantitative food frequency questionnaire. The IL-6 concentration was significantly increased in individuals with CRC (OR Q4 vs. Q1, 95% CI = 6.23, 4.10–9.45, p < 0.001). High dietary ORAC showed an inverse association with CRC (total ORAC OR Q4 vs. Q1, 95% CI = 0.26, 0.16–0.40, p < 0.001; total phenolics = 0.32, 0.21–0.50, p < 0.001). We found that low dietary ORAC was associated with a significant increase in CRC in the group with elevated IL-6 levels (total ORAC OR Q4 vs. Q1, 95% CI = 4.34, 3.12–6.02, p < 0.001; total phenolics = 4.61, 3.33–6.39, p < 0.001). This study suggested an inverse association between dietary antioxidant capacity and IL-6 level among patients with CRC.
Highlights
Colorectal cancer (CRC) is the third most common cancer and the second most common cause of death worldwide [1]
According to the subgroups of dietary oxygen radical absorbance capacity (ORAC), we found that a high level of IL-6 was strongly associated with an increased the risk of colorectal cancer (CRC) in the lower intake of hydrophilic ORAC (H-ORAC), lipophilic ORAC (L-ORAC), total ORAC (T-ORAC), and total phenolics (TPs) groups in the comparison between the highest and lowest quartiles as follows: H-ORAC (OR Q4 vs. Q1, 95% confidence intervals (CIs) = 4.26, 3.07–5.91, p < 0.001); L-ORAC (OR Q4 vs. Q1, 95% CI = 4.70, 3.38–6.52, p < 0.001); T-ORAC (OR Q4 vs. Q1, 95% CI = 4.34, 3.12–6.02, p < 0.001); and TPs (OR Q4 vs. Q1, 95% CI = 4.61, 3.33–6.39, p < 0.001), after adjusting for the aforementioned confounding variables
Higher dietary ORAC was inversely associated with the risk of CRC in the subgroup with elevated plasma IL-6 levels
Summary
Colorectal cancer (CRC) is the third most common cancer and the second most common cause of death worldwide [1]. The incidence and mortality patterns and trends in CRC burden have demonstrated that the development of CRC is linked to dietary pattern, lifestyle factors, obesity, family history of CRC, and inflammatory bowel disease (IBD) [1,2]. The World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) has indicated the known major risk factors for CRC and has revealed that diet, nutrition, and physical activity reduce the risk of CRC [3]. The association of chronic inflammation with CRC has been described in the growing literature. Chronic inflammation may give rise to oncogenesis in the context of CRC via continual unregulated proliferation, apoptosis and genetic mutations [4,5]. The activation of the immune response in immune cells produces inflammatory cytokines that may lead to the development and progression of Antioxidants 2019, 8, 595; doi:10.3390/antiox8120595 www.mdpi.com/journal/antioxidants
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