Plain language summary
Low-grade chronic inflammation contributes to the development of various chronic conditions like diabetes mellitus type2, chronic kidney disease, stroke, atherosclerosis, cardiovascular diseases, and cancer. Anthocyanins, a member of the flavonoid family, are water-soluble pigments that give plants their red-orange to blue-violet colours and have been shown to have antioxidant properties. The aim of this review and meta-analysis of 32 randomised controlled trials was to evaluate the impact of pure anthocyanins or anthocyanin-rich extracts/powders on inflammatory markers. The quality of studies for the meta-analysis was high for the inflammatory markers CRP (C-reactive protein), IL-6, TNF-alpha, adiponectin, and VCAM-1. There was a significant reduction in the pro-inflammatory CRP, IL-6, TNF-alpha and VCAM-1, and a significant increase in the anti-inflammatory adinopectin. Quality of studies was poor for other inflammatory markers evaluated. Higher doses tended to have a bigger positive effect. The authors conclude that anthocyanins may reduce inflammation.
Anthocyanins are natural bioactive compounds that have several health benefits. This systematic review and meta-analysis assessed the impact of dietary anthocyanins on markers of systemic and vascular inflammation. Meta-analysis of 32 randomised controlled trials indicated that dietary anthocyanins significantly decreased levels of C-reactive protein (CRP; -0.33 mg/l, 95% CI: -0.55 to -0.11, P = 0.003), interleukin-6 (IL-6; -0.41 ρg/ml, 95% CI: -0.70 to -0.13, P = 0.004), tumor necrosis factor-alpha (TNF-α; -0.64 ρg/ml, 95% CI: -1.18 to -0.09, P = 0.023), intercellular adhesion molecule-1 (-52.4 ng/ml, 95% CI: -85.7 to -19.1, P = 0.002), and vascular adhesion molecule-1 (VCAM-1; -49.6 ng/ml, 95% CI: -72.7 to -26.5, P < 0.001) while adiponectin level was significantly increased (0.75 μg/ml, 95% CI: 0.23 to 1.26, P = 0.004). The levels of interleukin-1β (IL-1β; -0.45 ρg/ml, 95% CI: -3.77 to 2.88, P = 0.793) and P-selectin (-6.98 ng/ml, 95% CI: -18.1 to 4.15, P = 0.219) did not significantly change. Subgroup analyses showed that administration of higher doses of anthocyanins (>300 mg/day) significantly decreased levels of CRP, IL-6, TNF-α, and VCAM-1. The results indicate that dietary anthocyanins reduce the levels of systemic and vascular inflammation in the subjects.