Effect of phylloquinone (vitamin K1) supplementation for 12 months on the indices of vitamin K status and bone health in adult patients with Crohn's disease

Interventional human study in adults with Crohn's disease in clinical remission recruited from an IBD clinic in Cork, Ireland. Study A was a short-term randomized dose-ranging trial with active arms of 10 participants each; Study B was a 12-month randomized trial with 43 participants assigned to the 1000 mg/day phylloquinone arm and 43 to placebo.

This paper evaluated oral phylloquinone (vitamin K1) supplementation in adults with Crohn's disease in remission. In the dose-ranging Study A, active arms received 1000 mg/day or 2000 mg/day for 2 weeks; in Study B, the active arm received 1000 mg/day phylloquinone daily with calcium 500 mg/day and vitamin D3 10 mg/day for 12 months, compared with placebo in a 1:1 design.

Phylloquinone clearly improved vitamin K status, but it did not translate into meaningful bone health benefits over 12 months. In Study A, %ucOC fell from 47% at baseline to 28.1% with 1000 mg/day and 28.95% with 2000 mg/day, with both doses better than baseline (P<0.01) and no difference between doses. Serum phylloquinone increased dose-responsively from 0.64 (0.50-1.54) nmol/l pre-intervention to 3.42 (2.58-9.24) nmol/l with 1000 mg/day and 16.4 (8.55-25.5) nmol/l with 2000 mg/day, versus 0.63 (0.54-1.05) nmol/l with placebo (P<0.0001). Over 12 months, there were no significant changes in bone turnover markers or lumbar spine/femur bone mass, although total radius BMD increased modestly (P<0.05).

Small active-arm sample sizes, especially in the 2-week dose-ranging phase, limit precision. The 12-month trial was single-center and used calcium plus vitamin D3 alongside phylloquinone, which complicates attribution of any bone-related effects to vitamin K1 alone. Short duration for skeletal outcomes and a Crohn's remission population may also limit generalizability.