Vitamin K1 Supplementation Did Not Alter Inflammatory Markers and Clinical Status in Patients with Rheumatoid Arthritis (Shishavan NG et al.)

International Journal for Vitamin and Nutrition Research has published results of an Iranian double-blind placebo controlled trial that examined whether vitamin K is a useful strategy for reducing inflammation in rheumatoid arthritis (RA) subjects.

Over the past decade the incidence rate of this autoimmune inflammatory disorder has dramatically increased in developing countries such as Iran. The researchers randomly allocated 58 female patients with definitive RA into two groups to receive vitamin K1 as phylloquinone [10 mg/day] or placebo pills for 8 weeks. At baseline and at the end of intervention they assessed the clinical status using disease activity score-28 (DAS-28) and serum concentrations of some inflammatory markers (IL-6, hs-CRP, TNFα).

The authors noticed no significant differences between the two groups regarding any of the baseline characteristics, and they concluded, “Vitamin K1 supplementation at 10 mg/day for 8 weeks had no significant effects on blood biomarkers of inflammation and disease severity of patients with rheumatoid arthritis compared with the placebo group.”1

“The study shows that vitamin K1 does not affect inflammatory markers in RA patients,” says Dr. Katarzyna Maresz, president of the International Science and Health Foundation. “Based on a previous randomized clinical trial (Abdel-Rahman et al. 2015)2 designed to clarify the therapeutic role of MK-7 added to normal therapeutic regimen of RA in patients with different stages of the disease, we know that vitamin K2 was beneficial in this group of patients,” she points out. In another study that Dr. Maresz quotes (Khojah et al. 2017), the authors confirmed the role of vitamin K2 in the treatment and early prophylaxis of RA: “[…] serum levels of vitamin K homologs were reduced in RA patients, and the levels of menaquinone-4 (MK-4) and menaquinone-7 (MK-7) [vitamin K2] were moderately to strongly inversely correlated with the clinical articular features in RA patients, whereas phylloquinone (PK) [vitamin K1] levels were weakly correlated.”3


  1. Shishavan NG, Gargari BP, Jafarabadi MA, Kolahi S, Haggifar S, Noroozi S (2018) Vitamin K1 Supplementation Did Not Alter Inflammatory Markers and Clinical Status in Patients with Rheumatoid Arthritis, International Journal for Vitamin and Nutrition Research 88(5-6): 251-257, doi: 10.1024/0300-9831/a000276.
  2. Abdel-Rahman MS, Alkady EA, Ahmed S (2015) Menaquinone-7 as a novel pharmacological therapy in the treatment of rheumatoid arthritis: A clinical study, Eur J Pharmacol. 761:273-8, doi: 10.1016/j.ejphar.2015.06.014.
  3. Khojah HM, Ahmed S, Abdel-Rahman MS et al. (2017) Vitamin K homologs as potential biomarkers for disease activity in patients with rheumatoid arthritis, J Bone Miner Metab 35 (5): 529–535, doi:10.1007/s00774-016-0785-4


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