Synbiotic supplementation and the effects on clinical and metabolic responses in patients with rheumatoid arthritis: a randomised, double-blind, placebo-controlled trial (Publication with Expression of Concern. See vol. 127, pg. 156, 2022)

Synbiotic intake may be associated with reduced inflammation in patients with rheumatoid arthritis (RA) due to optimised inflammatory markers, oxidative stress and insulin resistance. This research was conducted to assess the effects of synbiotic supplementation on the clinical and metabolic parameters of patients with RA. A total of fifty-four patients with RA were allocated into two groups to receive either a synbiotic capsule (n 27) or a placebo (n 27) for 8 weeks in this randomised, double-blind, placebo-controlled trial. Fasting blood samples were taken at baseline and week 8 of the study to quantify related markers. After the 8-week intervention, compared with the placebo, synbiotic supplementation resulted in a significant reduction in serum high-sensitivity C-reactive protein (hs-CRP) levels (-1427.8 (sd 3267.2) v. +2833.4 (sd 5639.7) ng/ml, P= 0.001). In addition, compared with the placebo, synbiotic supplementation improved disease activity score-28 joints (DAS-28) (-1.6 (SD 0.8) v. -0.3 (SD 0.5), P < 0.001) and visual analogue scales (VAS) pain (-30.4 (SD 18.7) v. -11.5 (SD 15.9), P < 0.001). In addition, a significant elevation in plasma nitric oxide (NO) (+0.8 (SD 4.4) v. -2.6 (SD 4.5) mu mol/l, P= 0.008), and significant reductions in insulin values (-13.8 (SD 26.4) v. +4.2 (SD 28.2) mu mol/l, P=0.01), homoeostasis model of assessment-estimated insulin resistance (HOMA-IR) (-0.5 (SD 1.0) v.+0v1 (SD 1.1), P= 0.03) and homoeostatic model assessment-beta-cell function (HOMA-B) (-9.4 (SD 17.9) v. +3.3 (SD 18.9), P=0.01) following supplementation with the synbiotic compared with the placebo. Compared with the placebo, synbiotic supplementation also resulted in a significant increase in plasma GSH (+36.6 (SD 63.5) v. -58.5 (SD 154.4) mu mol/l, P= 0.005). Overall, our study demonstrated that synbiotic supplementation for 8 weeks among patients with RA had beneficial effects on hs-CRP, DAS-28, VAS, NO, insulin levels, HOMA-IR, HOMA-B and GSH levels.