New research points to a clear, everyday move you can try: loading your plate with leafy greens may help preserve lung health. The study compared two forms of vitamin K, tracked nearly 180,000 people for over a decade, and linked higher vitamin K1 intake to stronger lung function and a lower risk of COPD. It did not find the same benefits for vitamin K2, and the results are observational rather than proof of cause and effect.
Vitamin K comes in two common dietary forms with very different profiles. Vitamin K1 is abundant in green vegetables and helps the body manage blood clotting, which is its best-known job. Vitamin K2 appears in fermented foods, certain dairy, eggs and meats, and it plays a role in directing calcium and supporting bone health.
Researchers at Edith Cowan University set out to see whether these vitamins mattered for breathing problems like chronic obstructive pulmonary disease and asthma, and whether they affected lung function. “Chronic respiratory diseases, including chronic obstructive pulmonary disease (COPD) and asthma, are among the most prevalent noncommunicable diseases worldwide and were the third leading cause of death in 2019, accounting for 4 million deaths and affecting 454.6 million individuals globally,” the scientists reported in the introduction to their study, published in The American Journal of Clinical Nutrition. “Although asthma and COPD can be managed with available treatments, neither condition is curable, underscoring the need for effective prevention strategies.”
The team analyzed dietary and health data from 179,062 people over roughly 10 and a half years and tracked diagnoses and lung performance. “Higher dietary vitamin K1 intake was associated with better lung function and a lower rate of COPD.” That link was strongest among current and former smokers and those who worked in jobs with more respiratory hazards, suggesting K1 might offer more relative protection when lungs face repeated insults.
By contrast, eating more vitamin K2 did not show a connection with lower COPD rates in this analysis. “No association was observed for vitamin K1 or vitamin K2 intakes and asthma,” the researchers also wrote. Because the study observed people rather than assigning diets randomly, the patterns are associations that point to promising leads but stop short of proving direct cause and effect.
Smoking remains the leading cause of COPD, and long-term exposure to dust, chemical fumes and pollution also drives risk for the disease. The investigators and collaborators speculated about possible biology behind the results, noting it’s likely vitamin K helps activate proteins that keep lung tissue more flexible and less prone to damage, which could explain improved lung measures in people eating more leafy greens.
The practical takeaway is simple and low-effort: boost green vegetables. Just one extra serving of leafy greens “is an achievable way to boost your vitamin K1 intake,” said Chengfeng Li, one of the study’s researchers. Think spinach, kale, collard greens, Swiss chard, Brussels sprouts or turnip greens as easy swaps or additions to meals.
This line of research is encouraging because it highlights a low-risk dietary change that fits into broader healthy eating. While more work is needed to confirm mechanisms and rule out confounding factors, adding a few more leafy servings is a sensible move for overall nutrition and could be a small step toward protecting long-term lung function.
