Eating a healthier diet may do more than support the heart and control body weight.
A large study suggests that people who eat better-quality foods may also have healthier lungs, with particularly noticeable benefits among people living with asthma or chronic obstructive pulmonary disease, known as COPD.
The research was led by Arturo F. Martinez-Rodriguez of the University of Groningen in the Netherlands and colleagues.
The study was published in ERJ Open Research and used information from the Lifelines study, a large research project that follows people in the Netherlands over many years.
COPD is a long-term lung disease that makes breathing increasingly difficult.
It includes conditions such as emphysema and chronic bronchitis and is commonly linked to smoking, although air pollution, workplace exposures, genetics, and other factors can also contribute.
Asthma is different from COPD, although both can cause coughing, wheezing, chest tightness, and shortness of breath. Asthma often involves inflammation and narrowing of the airways that can change over time, while COPD usually causes more persistent breathing problems and a gradual loss of lung function.
Age naturally affects the lungs as well. Lung function usually reaches its highest level in early adulthood and then slowly declines, but smoking, disease, pollution, infections, and other factors can speed up this process.
Researchers have long studied exercise and smoking as important influences on respiratory health. Diet has received growing attention because foods can affect inflammation, body weight, blood vessels, the immune system, and other processes that may also influence the lungs.
For the new study, researchers examined whether overall diet quality was related to lung function and whether the relationship differed among people with asthma, COPD, or neither condition. Instead of focusing on one food or nutrient, they used a diet score designed for the Lifelines research project.
A higher score represented a healthier overall eating pattern. This approach is useful because people eat combinations of foods, and the effects of a complete diet may be more meaningful than the effects of a single vitamin or ingredient.
The researchers measured lung function using a common breathing test called spirometry. During this test, a person takes a deep breath and then blows forcefully into a machine that measures how much air can be expelled and how quickly it comes out.
One measurement, called FEV1, records how much air a person can force out during the first second. Another, FVC, measures the total amount of air that can be forcefully breathed out, while the relationship between these measurements helps doctors understand whether airflow is limited.
The first part of the analysis included 83,460 adults. Researchers found that people with higher diet-quality scores generally had better lung function, and the relationship appeared particularly strong for some measurements among people with asthma or COPD.
The researchers also studied changes over time in 37,752 participants who had repeated measurements during roughly 10 years of follow-up. Among people with COPD, a higher-quality diet was associated with a slower decline in several important measures of lung function.
This finding is potentially important because COPD can gradually reduce a person’s ability to breathe and remain physically active. There is currently no simple way to restore lung tissue that has already been permanently damaged, so slowing further loss of function is an important goal.
The results do not prove that improving diet will directly prevent COPD progression or restore damaged lungs. This was an observational study, meaning researchers identified relationships between people’s eating patterns and lung function rather than assigning people to different diets and testing the results under controlled conditions.
People who eat healthier diets may also exercise more, smoke less, have better access to health care, or differ in other ways that influence respiratory health. Researchers can adjust their analyses for many of these differences, but it is difficult to remove every possible influence.
Even with that limitation, the large number of participants and long follow-up period make the findings valuable. Measuring several aspects of lung function also provides a broader picture than relying only on symptoms reported by participants.
The study adds to evidence that respiratory health may be connected with overall lifestyle rather than being influenced only by smoking or air quality. A nutritious diet cannot replace inhalers, smoking cessation, vaccinations, exercise, or other treatments recommended for asthma and COPD.
However, diet is something that people can change, making it an interesting target for future research. Clinical trials could test whether specific healthy eating patterns actually slow lung-function decline in people with COPD and determine which foods or nutrients may be most important.
Overall, the findings are encouraging but should be interpreted carefully. They suggest that healthier eating and better lung function travel together, particularly in COPD, but they do not yet show that diet itself is responsible for the difference.
For people with chronic lung disease, the study provides another reason to consider nutrition as part of broader health care. The strongest message is not that one food can protect the lungs, but that long-term eating patterns may be one of several factors that help support respiratory health as people age.
