A double-blind, randomized, placebo-controlled study to explore the efficacy of a dietary plant-derived polysaccharide supplement in patients with rheumatoid arthritis

There is increased interest in the potential benefits of complementary therapies, of which dietary plant-derived polysaccharides (dPPs) are an important component. We examined the impact of oral ingestion of a pre-biotic dPP supplement active compound (AC) on serum glycosylation and clinical variables associated with inflammation and general health in patients with RA. A double-blind, placebo-controlled, parallel-group clinical trial was used. Participants were randomly assigned to receive AC (n = 33) or placebo (n = 36) for 6 months. Serum protein N-glycosylation was determined by mass spectrometry. Patient outcomes were assessed by validated clinical trial health questionnaires. The primary clinical efficacy variable was DAS-28. The groups had comparable baseline clinical characteristics. AC was well tolerated with low drop-out rates. Supplementation resulted in a 12% significant drop in the levels of the agalactosylated (G0F) glycans [8.10 (0.89) to 7.16 (0.60); P = 0.03], but had no significant overall effect on patient outcomes. The placebo-treated group showed no change in G0F but exhibited a reduction in the levels of fully digalactosylated (G2) glycans (11%; P = 0.03). Although not clinically significant, DAS scores were, however, marginally lower in the placebo group [difference = 0.63 (0.23) s.e.; 95% CI 0.17, 1.10; P = 0.009], as were two of the secondary variables. Short-term dietary supplementation with AC resulted in a moderate, but significant, reduction in G0F levels, but did not result in any clinically significant improvement in disease activity when assessing the study group as a whole.