“Considering that vitamin K is important for regulating lung health and blood clotting, vitamin K deficiency during COVID-19 may make both those problems worse,” explain Dr Rob Janssen and Jona Walk, Researchers at the Canisius Wilhelmina Hospital (Nijmegen, the Netherlands), and lead authors of the study.

The “triage theory” implies that, because vitamin K1 is preferentially transported to the liver, carboxylation grades are higher in hepatic coagulation factors than in extra-hepatic proteins.

Yet, these extrahepatic proteins play a decisive role during COVID-19 infection. Insufficient activation of protein S in blood vessel walls and matrix Gla protein (MGP) in the lungs may lead to an increased risk for thrombosis and lung damage, respectively.

“Because of their structural differences, vitamins K1 and K2 do not have the same biological activities. With K2, the role of vitamin K extends beyond blood clotting, as it also regulates other important metabolic processes, such as calcification and inflammation."

"K1 is easily found in a balanced diet, which is not the case for K2. Deficiency might be more common than we think,” says Dr Trygve Bergeland, VP Science at Kappa Bioscience, who supported the research. 

The review also highlights the important link between vitamin D3 and vitamin K2. Vitamin D administration, which is part of certain clinical trials protocols for COVID-19, may induce short-term hypercalcaemia, resulting in an accelerated elastic fibre calcification and degradation. 

“Vitamin D administration in a state of vitamin K deficiency may thereby endanger pulmonary and vascular health,” notes Janssen.

“There is a need for further experimental evidence to link vitamin K deficiency with the pathology of COVID-19 and determine whether vitamin K2 supplementation has a place in treatment protocols."

"The potential role of vitamin K2 supplementation to prevent development of severe COVID-19 in subjects who have not yet contracted COVID-19, but are at risk for the infection, is also very relevant to assess,” Janssen and Walk conclude.

Kappa Bioscience, who supported this study, is entering research agreements with several research centres, both in Europe and in the US. The company aims to support research to generate a better understanding around vitamin K2 deficiency and COVID-19 pathogenesis.