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Functional Food

New Study Links This Overlooked Vitamin To Stronger Lung Function

Author: Zhané Slambee

April 28, 2026

mindbodygreen editor

By Zhané Slambee

Image by Nataša Mandić / Stocksy

April 28, 2026

Vitamin K is best known for its role in blood clotting and bone health. Now new research1 suggests it may deserve a spot in the conversation about lung health and respiratory wellness, too.

About the study

Vitamin K comes in two main forms: K1, found in leafy greens like kale and spinach, and K2, found in fermented foods and animal products. Both play a role in blood clotting and how your body handles calcium, but researchers wanted to know if either form might also support lung health.

To find out, they analyzed data from over 179,000 people in the UK Biobank, tracking their diets and lung function over 10.5 years.

Higher K1 intake was linked to a lower COPD risk

People who ate more vitamin K1 had a 16% lower chance of developing COPD compared to those who ate less. They also performed better on two key tests that measure how well your lungs move air in and out.

The benefits seemed to level off around 250 µg per day, roughly what you'd get from one serving of kale or about 1½ to 2 cups of uncooked leafy greens. Eating more than that didn't appear to add extra protection.

K2 didn't show the same connection to COPD risk, and neither form of vitamin K was linked to asthma. The researchers also noticed the association between K1 and lung function was strongest in smokers and people who work in jobs that expose them to dust, fumes, or other lung irritants.

Why K1 may support respiratory health

This study can't prove that vitamin K1 directly protects your lungs, but there are a few reasons it might help. Vitamin K helps keep calcium where it belongs: in your bones, not in soft tissues like your lungs. It also has anti-inflammatory effects, which could help slow down the kind of damage that leads to COPD over time.

Why is K1 more strongly linked to lung function? It likely comes down to how the body processes them. K1 gets picked up by the liver quickly and may have broader effects on inflammation, while K2 tends to hang around in the bloodstream and concentrate in other tissues.

How to get more vitamin K1 from leafy greens

The best sources of K1 are dark leafy greens:

- Kale (one cup cooked provides around 500 µg)

- Spinach

- Collard greens

- Swiss chard

- Broccoli

Even a daily side salad with mixed greens can help you reach the 250 µg mark this research points to. Building healthy eating habits that include more greens is a simple way to boost your intake.

Since vitamin K is fat-soluble, pairing your greens with a healthy fat (olive oil, avocado, or nuts) helps your body absorb it better.

Keep in mind: If you take blood thinners like warfarin, check with your doctor before making big changes to your vitamin K intake, since it can affect how the medication works.

The takeaway

This large study adds lung health to vitamin K1's growing list of potential benefits, alongside bone strength and cardiovascular support. While more research is needed, adding a serving or two of leafy greens to your plate is a simple way to support your respiratory health.

1 Source

- https://pubmed.ncbi.nlm.nih.gov/42025963/