A new, large study -- published Aug. 10 in ERJ Open Research -- suggests that people who have low levels of this vitamin also have less healthy lungs. They are more likely to report having asthma, chronic obstructive pulmonary disease (COPD) and wheezing.
"Our results suggest that vitamin K could play a part in keeping our lungs healthy,” said researcher Dr. Torkil Jespersen of Copenhagen University Hospital and the University of Copenhagen in Denmark.
“On their own, our findings do not alter current recommendations for vitamin K intake, but they do suggest that we need more research on whether some people, such as those with lung disease, could benefit from vitamin K supplementation,” Jespersen said in a journal news release.
In addition to leafy greens, vitamin K is found in vegetable oils and cereal grains. It has a role in blood clotting, helping the body heal wounds, but researchers know very little about its role in lung health.
To study this, the Danish researchers recruited more than 4,000 Copenhagen residents, ages 24 to 77.
Study participants underwent lung function testing, called spirometry, which measures the amount of air a person can breathe out in one second (forced expiratory volume or FEV1) and the total volume of air they can breathe in one forced breath (forced vital capacity or FVC).
Participants also gave blood samples and answered questionnaires on their health and lifestyle. The blood tests included a marker of low levels of vitamin K in the body.
People with markers of low vitamin K levels had lower FEV1 and lower FVC on average. Those with lower levels of vitamin K were also more likely to say they had COPD, asthma or wheezing. The study only found an association between vitamin levels and lung function; it couldn't prove cause and effect.
“This study suggests that people with low levels of vitamin K in their blood may have poorer lung function. Further research will help us understand more about this link and see whether increasing vitamin K can improve lung function or not,” said Dr. Apostolos Bossios, from Sweden's Karolinska Institute and secretary of the European Respiratory Society assembly on airway diseases, asthma, COPD, and chronic cough. He was not involved in this research.
"In the meantime, we can all try to eat a healthy, balanced diet to support our overall health, and we can protect our lungs by not smoking, taking part in exercise and doing all we can to cut air pollution,” Bossios said in the release.
The U.S. National Institutes of Health has more on vitamin K.
SOURCE: EJR Open Research, news release, Aug. 10, 2023