Lower levels of the nutrient were also associated with conditions such as asthma, chronic obstructive pulmonary disease (COPD), and wheezing, the ERJ Open Research study suggests.
‘Very little research’ into link with lung health
Asked about the mechanism behind this, researcher Dr Torkil Jespersen told Vitafoods Insights: “Our study was a cross-sectional study, meaning we cannot make any claims about causality.
“It is possible that lower vitamin K status causes poorer lung function since vitamin K-dependent proteins are needed to stop lung tissue from degrading, but it is also possible that lung damage increases the need of vitamin K.
“There is also the possibility that during childhood, lower vitamin K status and/or an unhealthy lifestyle lead to poor lung development.”
Vitamin K – found in leafy green vegetables, vegetable oils, and cereal grains – plays a role in blood clotting and wound healing.
Jespersen added: “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.
“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.”
‘Too early’ to make recommendations on supplementation
The study, which was led by a team of researchers at Copenhagen University Hospital and the University of Copenhagen, involved a group of 4,092 people aged 24 to 77 years.
Participants took part in spirometry tests, gave blood samples, and answered questionnaires about their health and lifestyle.
Spirometry 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). The blood tests included a marker for low levels of vitamin K in the body known as dp-ucMGP.
People with markers of low vitamin K levels had lower FEV1 and lower FVC on average, the researchers found. They were also more likely to report suffering from COPD, asthma, or wheezing.
“It is too early to recommend people to take vitamin K supplements to prevent or treat lung diseases, and there is no evidence to support this,” said Jespersen. “In the future, there might be great industrial potential, with further studies, if they show that vitamin K supplements may prevent and/or treat age-related diseases.
“This is not only limited to chronic lung diseases, but also conditions like osteoporosis and cardiovascular disease.”
He added: “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.”
Trial to examine vitamin K impact on lung, heart, and bone health
The researchers are working on a large clinical trial comparing vitamin K supplementation with placebo to examine the effects on heart and bone health in the general population. Based on these latest results, they will now include analyses of lung function as well.
Jespersen said: “Future research should focus on how vitamin K supplements are related to chronic and age-related diseases (including lung disease) over time. Several authors of the article are currently conducting a long-term, randomised, placebo-controlled study (InterVitaminK) on exactly this question.”
Dr Apostolos Bossios, from Sweden’s Karolinska Institute, is secretary of the European Respiratory Society’s Airway Diseases, Asthma, COPD, and Chronic Cough Assembly.
He said: “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.
“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.”
