Can the human body produce vitamin K2 on its own?

Vitamin K2 (menaquinone) can be significantly synthesized by the gut microbiota; however, without milk and lactose and with disrupted microbiota, a person loses one of the key pathways for the endogenous synthesis of vitamin K2.

Main sources of vitamin K2 in the body

Endogenous synthesis — by the flora of the large intestine, especially lactose-positive bacteria (Lactobacillus, Bifidobacterium, etc.). These bacteria use lactose as an energy source. During fermentation, they produce short-chain fatty acids and — among other things — menaquinones (primarily forms K2-MK-7, MK-8, MK-9).

If there is no lactose and a person does not consume dairy products:

• The lactose-positive flora suffers, and its numbers decrease.
• The level of vitamin K2 synthesis decreases.

If lactose-negative or pathogenic flora (e.g., Klebsiella, Clostridium difficile, etc.) predominates in the intestine, they do not synthesize K2 in bioavailable forms.

Intake from food — fermented products, fatty dairy products, eggs, liver, etc.

Conversion from vitamin K1 — in the tissues of the body (to a lesser extent).

Possible sources of K2 in the absence of lactose

If you do not consume milk, K2 can be obtained:

• from fermented products (natto, kimchi, sauerkraut),
• from eggs, liver, butter (MK-4),
• from supplements (MK-4 or MK-7),
• by restoring the microbiota with prebiotics (e.g., galacto-oligosaccharides) that stimulate the growth of the necessary flora even without lactose.

Conclusion

If the diet lacks lactose, and a person has a predominance of lactose-negative or pathogenic microbiota, then endogenous synthesis of vitamin K2 decreases sharply or stops.

Without external intake of K2 or restoration of the microbiota — the body risks facing multiple calcium metabolism disorders, including:

• demineralization of bones,
• calcification of blood vessels and soft tissues,
• and acceleration of aging processes.