Around 30 million Americans are living with chronic obstructive pulmonary disease (COPD) – close to double the number of those officially diagnosed – making it one of the deadliest health conditions worldwide. While frontline treatment is generally medication to support and boost lung function, it's a surprisingly complex disease without a one-size-fits-all management plan and a good deal of conflicting advice on interventions like exercise.
In a new study, a collaborative team of COPD specialists from institutions including Johns Hopkins University and the University of Michigan have taken a novel approach to investigating ways to alleviate some of the symptoms of the disease that could meaningfully improve the quality of life of sufferers. And while the focus on nutrition is nothing new, this study is not about an overall dietary shift tied to weight loss, but homes in on the specific nutritional content of certain foods that could fight the inflammation behind some of COPD's most debilitating issues.
Our understanding of the roles of natural compounds that fall under the broad umbrella of antioxidants – such as lutein and polyphenols – is still a work in progress; it's widely accepted that they have positive impacts on a broad range of diseases and chronic conditions, but variables including their bioavailability and bioactivity, among many other factors, have made it a complex area of research.
As this 2022 review explained so well, it's hard to determine efficacy of such compounds when molecular structures are highly variable – as is the way each one of us metabolizes such nutrients. Essentially, "the exact mechanisms of action, effects, and bioavailability of plant antioxidants are still not fully recognized."
So with that caveat out of the way, this new study doesn't offer a quick fix for COPD – which is, unfortunately, incurable – but it does present an interesting new way of managing symptoms: through legumes and soy products. Specifically, the isoflavone content of these natural foods that, when boosted in the diets of COPD sufferers, appears to lessen the severity of breathing issues and coughing, and to improve lung health in general.
While COPD is often thought of as something just smokers or former smokers get – especially since emphysema is one of its presentations – it's estimated that between a quarter and half of those who develop the chronic condition have never smoked. This alone makes COPD such a complex issue, with current thought suspecting "genetic, infectious, socioeconomic, environmental and occupational factors" all play a role.
Given its prevalence in current and former smokers, this study did focus on this cohort, recruiting 99 participants with COPD to be followed for six months, with a range of tests conducted at baseline, three months and then at the conclusion of the trial.
People were not assigned a specific "dose" of soy products or legumes, but were instructed to just continue with their normal Western-style diet. Food diaries – while not perfect – helped researchers estimate likely isoflavone consumption, which sorted the participants into either a high intake or low intake group. Overall, the group had a mean isoflavone intake of around 1.8 mg/day – but the degree to which this amount varied is what proved interesting when it came to COPD symptoms.
Researchers assessed participants using several standard COPD measures, including looking at overall health status (COPD Assessment Test), symptom burden and daily functioning (Clinical COPD Questionnaire), and severity of symptoms such as coughing and mucus production. They also examined biomarkers related to platelet activation and inflammation.
After adjusting for overall diet, demographics and other variables common in observational studies, the team found that those with a higher intake of isoflavone-rich foods didn't just report improved COPD management, but showed key biomarker signs of improvement – including reduced platelet activation, which is linked to inflammation and cardiovascular problems.
Of course, this study was observational and didn't involve any dietary interventions or a control, and it was a relatively small sample size from which to draw definitive conclusions about the role isoflavone-rich foods play in mitigating COPD symptoms. However, those who had higher isoflavone consumption had fewer issues with breathing difficulties and a reduction in coughing, and they were also able to clear mucus more easily, impacting lung health.
So, while it's just preliminary, this study opens the door to further investigations around the role that foods like legumes and soy-rich products could play in managing COPD symptoms. As with all nutrition-based interventions, the key will be unraveling the mechanisms at play – particularly how isoflavone may fight inflammation.
"Research has proven diet and nutrition can impact lung health," said Daniel C. Belz, M.D., from the Division of Pulmonary and Critical Care Medicine and Johns Hopkins University and lead author of the study. "Additionally, larger studies are necessary to explore how increasing isoflavone consumption helps improve COPD symptoms and overall lung health."
The research was published in Chronic Obstructive Pulmonary Diseases: Journal of the COPD Foundation.
Source: COPD Foundation
