The Dynamics of the Colloidal Interplay of Bile and Vitamin K1

Vitamin K₁ is an essential cofactor for the posttranslational modification of Vitamin K₁-dependent proteins, regulating blood coagulation, bone mineralization, and anti-inflammatory processes. Its bile-dependent bioavailability points toward the importance of understanding its largely unknown interplay with bile. We detailed the interaction of Vitamin K₁ with bile using simulating intestinal fluids and studied the effects of bile on Vitamin K₁ solubilization and permeation across artificial membranes. Our results indicate that transitioning from fasted to the fed-state bile concentrations critically impacted Vitamin K₁ performances. In the fasted state, flux inversely correlated with the bile concentrations. Starting at the fasted-to-fed transition, this flipped, and Vitamin K₁ solubility increased 8-fold, while the flux increased up to 5-fold. When fed, Vitamin K₁ was mainly present in small colloidal species, maintaining Vitamin K₁ solubility and rapid exchange dynamics with the surrounding fluids. In conclusion, a fed state is a critical prerequisite for effective Vitamin K₁ solubilization and molecular presentation within the gastrointestinal tract. Analogous studies with Vitamin D₃, another lipophilic vitamin, provided evidence that the mechanism of bile interaction now detailed for Vitamin K₁ is not conserved across different vitamins. These outcomes detail Nature’s strategy for the nutritional exploitation of Vitamin K₁ by bile, with immediate relevance for diet plans and future nutraceutical designs.