This topic is all about understanding vitamin K2, especially for someone who has had a colectomy or ileostomy. The person in question is trying to figure out how to ensure they get enough vitamin K2, which is important for directing calcium to the bones rather than the arteries. Here are some key points and advice that might help:

1. **Conversion of Vitamin K to K2**
- Vitamin K-rich foods are converted to K2 in the body, but this process is mainly associated with the colon. Without a colon, this conversion might be less efficient, making dietary or supplemental K2 more important.

2. **Production of K2**
- While the colon can absorb K2 produced by bacteria, its removal means relying more on dietary sources or supplements. Some conversion of vitamin K1 to K2 can still occur in other tissues.

3. **Testing for Vitamin K2**
- There is a blood test for undercarboxylated osteocalcin, which indirectly measures K2 activity. This test is available through some specialized labs but is not yet a standard procedure.

4. **Consulting Professionals**
- It's recommended to consult with a dietitian or nutritionist who has experience with stoma care. They can provide tailored advice and might be more knowledgeable about the specific needs of someone with an ileostomy.

5. **Foods Rich in Vitamin K2**
- Some foods naturally contain K2, such as eggs, cottage cheese, aged or fermented cheeses, and fermented foods like natto. Emu oil is also a good source and can be ordered online.

6. **Supplements**
- There are over-the-counter supplements that combine vitamin D, calcium, and K2. These can be a convenient way to ensure adequate intake, especially if dietary sources are limited.

7. **Absorption Considerations**
- Vitamin K2 is absorbed in the jejunum and ileum, which are still present in those with an ileostomy. Absorption requires dietary fat, bile salts, and pancreatic enzymes.

8. **Regulatory Information**
- There is no established recommended daily intake for vitamin K2 by the FDA, which might be why it is not commonly addressed by dietitians.

9. **Additional Considerations**
- The person is already taking a supplement that includes vitamin D and K2 and is seeing an increase in vitamin D levels. They are also exploring the benefits of fermented foods and the different forms of K2 (MK-4 and MK-7).

10. **Seeking Further Testing**
- They plan to inquire with the UK NHS about the possibility of getting an undercarboxylated osteocalcin test to better understand their vitamin K2 status.

These insights and advice can help guide someone with an ileostomy in managing their vitamin K2 intake and ensuring their supplements and diet are working effectively for their health.