People who have higher levels of vitamin K, found in broccoli and spinach among other foods, appear to have better lung function, a preliminary study has suggested.
Those with higher levels of vitamin K – which the body needs for blood clotting, helping wounds to heal – were less likely to have asthma, chronic obstructive pulmonary disease or to wheeze, researchers found.
They were also more likely to perform better on lung health checks.
Vitamin K is found in green leafy vegetables as well as vegetable oils and cereal grains.
The researchers said their study was not enough to recommend that people take vitamin K supplements for lung health but they called for further research.
During the study, published in the journal ERJ Open Research, a team of Danish researchers from Copenhagen University Hospital and the University of Copenhagen examined more than 4,000 people living in Denmark's capital aged 24 to 77.
People involved in the study took part in lung function testing, called spirometry, gave blood samples and answered questionnaires on their health and lifestyle.
The blood tests showed whether or not people had low levels of vitamin K.
Eat your way to good health – in pictures
Meanwhile the spirometry test measured the amount of air a person can breathe out in one second and the total volume of air they can breathe in one forced breath.
Researchers found that people with low levels of vitamin K performed worse on these tests.
Meanwhile people with low levels of vitamin K were twice as likely to report that they had COPD, 81 per cent more likely to report that they have a wheeze and 44 per cent more likely to report having asthma.
“We already know that vitamin K has an important role in the blood and research is beginning to show that it’s also important in heart and bone health, but there’s been very little research looking at vitamin K and the lungs,” researcher Torkil Jespersen said.
“To our knowledge, this is the first study on vitamin K and lung function in a large general population. Our results suggest that vitamin K could play a part in keeping our lungs healthy.
“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.”
Commenting on the study, Apostolos Bossios, from the Karolinska Institutet in Sweden and secretary of the European Respiratory Society’s assembly on airway diseases, said: “Further research will help us understand more about this link and see whether increasing vitamin K can improve lung function or not.”
Samantha Walker, director of research and innovation at Asthma and Lung UK, said: “We’d be interested to see further research in this area so we can better understand if levels of vitamin K are directly associated with lung function, which could help us better understand the impact of diet on people with lung conditions.
“Research such as this is important, because lung conditions are the third biggest killer in the UK, but only 2 per cent of public funding is spent on research into lung conditions that would help diagnose, treat and manage them much more effectively.”