Is Vitamin K safe for low-sal folks?

Reviewed date: May 12, 2024

Uploaded date: May 12, 2024


Why I'm interested:  

Email response to inquiry I thought I'd share about Vitamin Ks (May 13, 2024)

Key Takeaways:
Vitamin Ks should be safe to consume for low-sal folks, but contains the risk that it does contain a phenol and is plant derived.
Why this is interesting or informative:

*This is not medical advice* Response to email inquiry

Overall, it should be safe for low-sal folks. I took 6000mcgs (x60 pills spread out over 3-4 months) and haven't had a reaction. I took Thorne's Vitamin K (this is an affiliate link, learn more).

For the inactive ingredients, I've heard of a few people to have reacted to the cellulose (pine), and the vitamin E does have a phenol in it, but it's not technically a salicylate. That said, I've known people (without salicylate sensitivity) to react to Vitamin E. I don't react to either.

I did have some blood tests back this month. Vitamin D is in the normal range now, and my intracellular levels are at the top of the range for K1, MK4, and MK7 (they don't list over ranges for these tests, just that the cells have what they need). I've since then decided I'm probably ok and don't need to supplement with K anymore, even though I'm continuing to take D. Please remember that K is a fat-soluble vitamin, so if you're on a high dose like Thorn's 6,000mcgs, that may be too much for too long. I think I'll probably do a maintenance dose of one pill a week or every other week now. I mention this, because you may be able to split the capsule and only take a smaller dose. You can do this by mixing it with a small amount of cream (or something oily/fatty), or just dumping out part of the capsule and taking a partial.

Here are a few adverse reactions I found for Ks in a database I have access to. I didn't dive into the sources, and some sources weren't provided.

  • Dermatologic ...Orally, intake of vitamin K2 (menaquinone) along with calcium and vitamin D3 can cause an increased incidence of skin and skin appendage lesions compared to taking calcium and vitamin D3 alone.
  • Gastrointestinal ...Orally, vitamin K can cause mild to moderate gastrointestinal side effects
    • Caluwé R, Vandecasteele S, Van Vlem B, Vermeer C, De Vriese AS. Vitamin K2 supplementation in haemodialysis patients: a randomized dose-finding study. Nephrol Dial Transplant. 2014;29(7):1385-90. View abstract.
    • Huang ZB, Wan SL, Lu YJ, Ning L, Liu C, Fan SW. Does vitamin K2 play a role in the prevention and treatment of osteoporosis for postmenopausal women: a meta-analysis of randomized controlled trials. Osteoporos Int. 2015;26(3):1175-86. View abstract.
  • Hepatic ...Orally, vitamin K3 (menadione) has been linked to hepatotoxicity.
  • Other ...Intravenously, vitamin K can cause reactions that resemble hypersensitivity or anaphylaxis
    • Riegert-Johnson, D. L. and Volcheck, G. W. The incidence of anaphylaxis following intravenous phytonadione (vitamin K1): a 5-year retrospective review. Ann.Allergy Asthma Immunol. 2002;89(4):400-406. View abstract.

Now, if you look at the molecular formula of the Vitamin Ks, you'll see there is a phenol on it (hexagon far left with 3 lines), attached to another ring (middle hexagon) and then the fatty tail. While it's not a salicylate, it may need to be metabolized through the same pathways, so there is always a risk, depending on your sensitivity and the amount you have. This is the same thing for Vitamin E.

This same paper states that Ks are from plant foods, and during fermentation, bacteria can make the K2s by releasing it. "Menaquinone-7 (MK7) is the menaquinone of fermentative origin found in the Japanese traditional food natto, a soybean product fermented using Bacillus subtilis natto." Note that soy has very mixed results related to salicylate levels but is generally well tolerated.

The last thing to remember, is that it looks like Vitamin K is sourced from plants, and K2s are from fermented plants. That said, we can make the assumption that there is always a risk of using plant-sourced supplements, as 100% purity cannot be acquired. I think overall, the risk is low - but still there.

I think that's all I can think of. You wrote me a while ago (sorry for the delay), so if you found a K that worked for you, let me know!


Source Information

Source Type: Email response-review by Sarah