vitamin k and gut bacteria

Vitamin K and Gut Bacteria

Vitamin K is an essential nutrient for blood clotting, bone health, and heart health.

Gut bacteria may play an important role in maintaining vitamin K stores in the body. The study highlights that the gut microbiota can transform vitamin K1 into vitamin K2, which is the biologically active form of vitamin K.

The journal:

Gut Microbes

The paper:

Dietary vitamin K is remodeled by gut microbiota and influences community composition (Mar 2021)

The authors: 

Jessie L. Ellis,J. Philip Karl,Angela M. Oliverio,Xueyan Fu,Jason W. Soares,Benjamin E. Wolfe,Christopher J. Hernandez,Joel B. Mason & Sarah L. Booth 

What is Vitamin K?

Vitamin K deficiency can lead to various health problems, including an increased risk of bone fractures, cardiovascular disease, and bleeding disorders. The two main forms of vitamin K are vitamin K1 (phylloquinone) and the biologically active form, vitamin K2 (menaquinone).  

How is Vitamin K absorbeed?

Vitamin K1 from dietary sources is absorbed in the small intestine and transported to the liver, where it is converted to vitamin K2 and then released into the bloodstream. However, the researchers suggest that some of the vitamin K1 that is not absorbed in the small intestine may be metabolized by gut bacteria in the large intestine, contributing to the overall pool of vitamin K2. The conversion of vitamin K1 to K2 involves the removal of a side chain, and this process is facilitated by specific bacterial enzymes.

Furthermore, the report suggests that the gut microbiota may play an important role in maintaining vitamin K homeostasis and preventing vitamin K deficiency. 

Which gut bacteria metabolise vitamin K?

According to the article, bacterial species that have been shown to be involved in vitamin K transformation include:

  • Bacteroides ovatus
  • Bacteroides thetaiotaomicron
  • Parabacteroides distasonis
  • Parabacteroides merdae
  • Blautia producta
  • Clostridium perfringens
  • Eggerthella lenta
  • Escherichia coli

The study also found that some bacterial species, such as Faecalibacterium prausnitzii, had limited activity in converting vitamin K1 to K2. The efficiency of vitamin K transformation varied among different bacterial strains and species.


To summarise, these findings have important implications for the development of probiotics and dietary interventions aimed at optimizing gut health. For example, probiotics containing specific strains of bacteria that are efficient in producing vitamin K2 could be beneficial for deficient individuals. Moreover, dietary interventions that increase the intake of vitamin K1 may also promote the growth of beneficial gut bacteria and improve overall gut health.

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