The investigators propose a pilot study (carried out to assess its feasibility on a larger scale) to evaluate if a supplement of vitamin K improves vitamin K serum levels in CF patients by comparing:~Group A: a vitamin K supplement of 2mg, every day for 6 months~Group B: a vitamin K supplement of 7mg, twice a week for 6 months
Cystic fibrosis (CF) patients are at risk for vitamin K deficiencies. Supplementation for fat-soluble vitamins A, D, and E is well established, but in CF, there is little data for vitamin K concerning the optimal dose and frequency of supplementation. Beyond its known role in coagulation, research has highlighted the role of vitamin K for bone health and the control of blood sugar levels. However, after pulmonary complications, the risk of diabetes and bone diseases are two important and frequent complications of CF. Patients with CF being at risk of vitamin K deficiencies, this vitamin could play a role in these complications.