“I take probiotics and fermented foods on a daily basis. My gut must be producing enough vitamin K2, so I’m covered, right?”
Not necessarily.
We can agree, the assumption makes sense that the gut bacteria do synthesize vitamin K2. The science confirms it. But here’s the catch that gut health enthusiasts rarely discuss i.e. your intestinal bacteria produce far less bioavailable K2 than you actually need, and modern lifestyles have made the problem exponentially worse.
The Absorption Problem: Location Matters
Yes, your gut bacteria produce menaquinones. In fact, intestinal production is thought to meet 10-50% of human vitamin K requirements (ScienceDirect, 2024). That sounds promising until you understand where this synthesis happens and how absorption works.
Bacterial K2 production is mainly done in the colon, especially by strains such as Bacteroides (MK-10 and MK-11), E. coli (MK-8), and Veillonella (MK-7). However, there is a catch: most of these menaquinones are actually bound to bacterial membranes found in the colon, making them have poor bioavailability in general (Frontiers in Immunology, 2021). Even if the gut bacteria are producing high amounts of MKs, diet still remains the primary source of available K2.
The scientific consensus is clear. Only exogenous K2 supplementation makes sense because of its fat solubility, which makes it possible to be absorbed in the duodenum and small intestine, not in the colon where most bacterial production takes place (PMC, 2023). Your gut bacteria are producing K2 in the wrong place, and your body can’t get it from there.
Modern Lifestyle: The Gut Microbiome Under Siege
Even if bacterial K2 were easily absorbed, modern life has systematically dismantled our capacity to produce it. Consider the factors working against your gut bacteria right now:
Use of antibiotics: An antibiotic course can change your gut microbiome permanently for 12 months, which can reduce your ability to produce certain vitamins (Medium 2025). Taking both antibiotics and anticoagulants could lead to increased risk of bleeding as antibiotics kill the bacteria that produce vitamin K2. Studies show that antibiotics also greatly reduce the Lactobacillus, Bifidobacterium, Firmicutes, and Clostridium populations in the gut, which are the primary producers of K2, and without supplementation, these populations will never be restored to their original levels (Science Direct 2023).
Processed Western diet: Most ultra-processed foods do not contain fiber or a variety of plants to feed the bacteria required to generate vitamins. When these bacteria do not receive enough nourishment, they cannot grow and cannot synthesize vitamins. Clinical data show that intestinal microbiota cannot produce enough K2 vitamins to offset inadequate dietary K amounts caused by processed foods (PMC 2023).
Inadequate dietary intake: Studies suggest MK synthesis will not compensate for short-term decreases in vitamin K dietary intake (Frontiers in Immunology 2021). This means your gut bacteria will not increase production fast enough to bridge the gaps.
Intestinal dysfunction and inflammatory bowel disease (IBD): IBDs, chronic renal disease, liver dysfunction, and restorative proctocolectomy can lead to a vitamin K deficiency state by affecting the bacterial flora of the gut or the absorption of vitamin K (Frontiers in Immunology 2021).
“Not All K2 Is Created Equal”
Here’s another complexity that different gut bacteria produce different menaquinone forms. Eubacterium lentum synthesizes MK-6, Veillonella produces MK-7, E. coli makes MK-8, while Bacteroides species produce MK-10 and MK-11 (Frontiers in Medicine, 2022).
The problem?
MK-7 to MK-13, which are synthesized by gut bacteria are not efficiently absorbed with relatively increasing longer isoprene units (Frontiers in Immunology, 2021). The longer the side chain, the worse the absorption becomes. So even when your bacteria produce these forms, your body struggles to use them effectively.
Conversely, MK-7 in its dietary form (particularly from fermented foods like natto or from high-quality supplements) exhibits superior bioavailability, higher bioactivity, and a significantly longer half-life in vivo compared to bacterially produced forms stuck in your colon.
How Terraqueno’s K2-7 Delivers What Your Gut Cannot
This is where strategic supplementation becomes essential and not as a replacement for gut health, but as recognition of its limitations.
Terraqueno’s K2-7 formula provides Menaquinone-7 in the precise form and location your body requires. It is readily absorbable in the small intestine (the primary site of absorption for fat-soluble vitamins) and will thus efficiently enter your blood stream. Our MK-7 is made by fermenting Bacillus subtilis, the same beneficial bacteria that have been used to produce traditional natto, resulting in a pharmaceutical-level of bioavailability that circumvents the difficulties associated with absorbing this vitamin from bacterial synthetization in the colon.
Clinical data supports the evidence that dietary K2-7 supplementation increases circulating K2 levels, decreases the amounts of under-carboxylated forms of osteocalcin and Matrix Gla Protein, and has proven cardiovascular (heart) and bone health benefits. None of these benefits can be seen through endogenous (within) bacterial formations (PMC, 2023).
Recent studies on the relationship between gut flora and Vitamin K revealed that supplemental K2 actually supports the growth of beneficial gut microbes. After vitamin K2 was added to the diet with an antibiotic therapy, levels of Lactobacillus, Bifidobacterium, Firmicutes, and Clostridium were restored (ScienceDirect, 2023). Supplementation does not replace your microbiome, it enhances it.
The Bottom Line
The value of gut health cannot be emphasized enough. A healthy, balanced gut microbiome is a gift that keeps on giving. However, to rely on your own bacteria to produce K2 in order to satisfy your own needs is like relying on your garden to provide for your family when you live in an apartment with poor sunlight and poor soil. It just isn’t the best scenario, even if you are taking great care of it.
At Terraqueno, we understand the complexity of microbiome science. We also understand its limitations. Our K2-7 supplement provides bioavailable menaquinone exactly where your body can utilize it most effectively; in addition to, not instead of, your body’s own natural processes.
Because a healthy gut is essential. But it’s not sufficient.
