Leafy Greens, Matcha Tea, Vitamin K, and COVID

“Let food be thy medicine.” At least with COVID-19, correlations continue to build, factoring diet more by the day in the outcomes of patients with the virus.

Trends of diet type, even consumption of specific foods grow more pivotal in the severity of the disease and the likelihood of recovery.

While a given, that healthy approaches to diet should carry an edge against infection, recent findings actually point towards a very specific vitamin...

Getting Familiar with Vitamin K

Yes, even the healthiest of diets may struggle with vitamin K. There are two primary forms, K1 and K2, each critically tasked with protecting blood vessels, arteries, and as COVID asserts – the lungs. 

These fat-soluble vitamins aid in the synthesis of certain proteins, but more familiarly are dubbed ‘clotting-factors’ as they regulate response to bleeding and arterial damage.

Can Vitamin K Protect against COVID?

Per COVID, researchers are learning more deeply the cardiovascular importance of vitamin K; the worst outcomes of coronavirus appear to impact those patients deficient in the vitamin.

  • Permanent or unrecoverable lung damage is more likely as the protective and regulatory benefits of vitamin K are reduced [1-2]
  • Vitamin K’s vital role in producing elastin, a protein which helps cells maintain and regain shape during (infectious) stress is at play [1,3] 

Am I getting enough Vitamin K?

COVID patients with poor outcomes correlate to onset of elastic-fiber degradation of lungs [1], presenting an urgent reminder of the less familiar vitamin K: is your diet receiving enough of this important vitamin?

COVID Risk Factors

Those most likely to die of COVID notably have a diet fewer in leafy greens, eggs, and fermented foods like hard (typically aged) cheeses.

Researchers are hopeful that simple addition of a healthy diet may play an important role in the virus’ course, especially for the case of vitamin K [1].

  • Foods high in vitamin K are reportedly safe to employ regularly –and specifically for COVID – the only consideration is if you are on blood-thinning medications [1], to talk with your physician first.

Differences between Vitamin K1 and K2

Forms of vitamin K follow many of the same functions, though are metabolized at different rates in the body, and may influence health differently (e.g. K1 may be more involved in bone health).

As is the case with other natural vitamin complexes, balanced consumption is reported relevant. Vitamin K2 is only produced by bacteria during anaerobic metabolism, which can happen inside (see gut-health) or outside the body (see fermented foods). 

Fermented Foods and Vitamin K

Fermented food products like aged cheeses [4], and the Japanese soybean dish ‘natto’ are therefore great examples of high K2 levels. The recent report associating vitamin K with mortality points to regions of Japan where natto is common.

  • There, significantly less coronavirus deaths have been reported. [1]

How to get More Vitamin K

Recommended daily intake of vitamin K is usually 150-200mcg (micrograms), but varies with age and health status. In order to increase these numbers in the wake of COVID, dietary sources largely include leafy greens. [5]

  • One serving of kale or chard confers up to 800mcg of vitamin K
  • Parsley, Brussels sprouts and spinach, between 400-500mcg

Tuning your diet towards vitamin K is one reasonable possibility to provide an upper-hand against coronavirus.

Does my Diet have enough Vitamin K?

Generally, food groups with vitamin K are broadly nutritious, though keep in mind that many staples (fruits, legumes) are surprisingly low in vitamin K [5].

Still, upping intake can come in many forms, simply being cognizant of how the foods you’re eating relate to this cardiovascular-vitamin may prove crucial.  

Green Tea and COVID

And, if you’re wondering where matcha green tea fits into the equation, it’s known to contain natural levels of both K1 and K2, though not quite as high as those leafy greens above.

Yes – Matcha Green Tea has Vitamin K

With matcha you’re not limited to water-solubility of regular tea (vitamin K instead is fat-soluble). A common serving size of matcha green tea may contain more than 10% of the recommended daily intake of vitamin K. [6]


The Bottom Line

Leafy greens and matcha are examples that are safe to enjoy multiple times per day, while making for a complementary approach to boosting nutritional status in the fight against coronavirus. 

By fortifying your diet you also are ingesting bioactive polyphenols and flavonoids, like in matcha which have been studied against COVID.

Ultimately, by paying attention to diet –  whether for vitamin K or otherwise – we can aim to be healthier, and more resilient to the ongoing pandemic. How does that look for you?


-Team Matcha Kari




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[1] Dofferhoff, A. S., Piscaer, I., Schurgers, L. J., Walk, J., Van Den Ouweland, J. M., Hackeng, T. M., ... & Janssen, R. (2020). Reduced Vitamin K Status as A Potentially Modifiable Prognostic Risk Factor in COVID-19.
[2] Speed, V., Patel, R. K., Byrne, R., Roberts, L. N., & Arya, R. (2020). A perfect storm: Root cause analysis of supra-therapeutic anticoagulation with vitamin K antagonists during the COVID-19 pandemic. Thrombosis Research.
[3] Piscaer, I., et al. (2019). Low Vitamin K Status Is Associated with Increased Elastin Degradation in Chronic Obstructive Pulmonary Disease. Journal of clinical medicine, 8(8), 1116.
[4] Vermeer, C., Raes, J., Van’t Hoofd, C., Knapen, M. H., & Xanthoulea, S. (2018). Menaquinone content of cheese. Nutrients, 10(4), 446. 
[5] Kamao, M., Suhara, Y., Tsugawa, N., Uwano, M., Yamaguchi, N., Uenishi, K., ... & Okano, T. (2007). Vitamin K content of foods and dietary vitamin K intake in Japanese young women. Journal of nutritional science and vitaminology, 53(6), 464-470.