Vitamin K has several forms
NIH distinguishes phylloquinone, or K1, from menaquinones, or K2. Food databases mainly report K1; K2 composition information is more limited. Before using a number for sauerkraut, check which form the analysis measured. [1]
Fermentation does not guarantee a uniform amount
Bacterial strains and fermentation conditions affect the forms and amounts in fermented foods. The cited fact sheet does not establish one reliable K2 dose for every serving of sauerkraut. A live-culture claim and a quantified vitamin measurement are also different types of information. [1]
Do not swap it for a prescribed regimen by guesswork
Imagine trying to replace a labeled K2 amount with spoonfuls of sauerkraut. Without suitable composition data, that calculation cannot be made accurately. If taking warfarin, maintain a consistent vitamin K intake and discuss major changes with the care team rather than assuming fermented foods have no relevance. [1]
| Situation | Interpretation |
|---|---|
| Total vitamin K value | Check which form was measured |
| Fermented food | Amount can vary |
| Warfarin use | Keep intake consistent |
Sources for this article
- Vitamin K - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.