Effects of Vitamin K on Matrix Metalloproteinase-3 and Rheumatoid Factor in Women with Rheumatoid Arthritis: A Randomized, Double-Blind, Placebo-Controlled Trial

Abstract

Objectives: Rheumatoid arthritis (RA) is an autoimmune disease characterized by an increase in some autoantibodies and proteolytic enzymes, leading to joint destruction. Although recent investigations have considered vitamin K as an anti-inflammatory nutrient with an important role in bone metabolism, there is currently limited information on its efficacy in RA. We aimed to examine the effects of vitamin K-1 (phylloquinone) on the biomarker of joint destruction and autoantibody in patients with RA. Materials and Methods: This was a randomized clinical trial in which 64 women with RA who fulfilled the eligibility criteria were randomly allocated to an intervention or a control group. Vitamin K-1 or placebo was administered to the participants for 8 weeks. Baseline characteristics and anthropometric measures were obtained. Clinical status using disease activity score in 28 joints (DAS-28), serum levels of matrix metalloproteinase-3 (MMP-3), and rheumatoid factor (RF) were assessed before and after the intervention. Results: The serum level of MMP-3 compared with the baseline values did not change significantly in the groups. However, the serum concentration of RF decreased significantly in the vitamin K-1 group (p = 0.041). Intergroup comparison showed no significant change in RF serum level after adjusting for relevant confounders (p > 0.05). Conclusions: Vitamin K-1 supplementation at 10 mg/day for 8 weeks did not alter joint destruction and immune status in the patients with RA compared with the controls.