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Chronic obstructive pulmonary disease is frequently associated with cardiovascular, metabolic, and psychological diseases, all of which can negatively impact quality of life, exacerbations, and prognosis. 

Although symptoms can often be effectively controlled through a combination of medical and pulmonary management, lifestyle interventions — like quitting smoking — have also been shown to help. Consideration of dietary patterns is also becoming part of the management toolbox. 

“There are a lot of studies that have looked at certain specific nutrients, vitamins, etc. But the focus is more on an overall dietary pattern,” Krista Mielnik, MS, RD, a registered dietitian with Cleveland Clinic’s Center for Human Nutrition, told Medscape Medical News. 

“Right now, the best diet pattern we have for COPD is the Mediterranean diet,” said Mielnik, “which encompasses all of the minerals and vitamins that patients have questions about due to the specific focus on certain foods (eg, vegetables, fruits, whole grains, unprocessed meats, and healthy fats).” 

Observational and interventional studies have shown the Mediterranean diet can help reduce cardiovascular risk factors and outcomes, type 2 diabetes, overweight and obesity, and cancer risk, including lung cancer. The first four represent the most common comorbidities in patients with COPD. 

“[The Mediterranean diet] also has anti-inflammatory benefits and is rich in fiber,” said Sandra Arévalo, MPH, RDN, spokesperson for the Academy of Nutrition and Dietetics, and director of Community Health & Wellness at Montefiore Nyack Hospital in Nyack, NY. “But it’s important to emphasize that the Mediterranean diet (or any food or diet) is not going to cure COPD.” 

COPD Paradigm

An important consideration when counseling patients with COPD about diet is that patients have different needs. Moreover, because symptoms can overlap with other diseases and common comorbidities, many patients do not receive a diagnosis until the disease has progressed. 

The approach “really depends on the type of patient and there are two types,” said Mielnik. “The first is the patient that is malnourished and dealing with frailty and sarcopenia.” 

“When this happens, patients have a lower exercise capacity and higher risk for exacerbations and death,” said MeiLan Han, MD, professor of medicine, chief of the Division of Pulmonary and Critical Care at the University of Michigan Health in Ann Arbor, and a spokesperson for the American Lung Association. 

The goal is to “bulk these patients, to become stronger and help their lungs, which in this case is a focus on calorie-dense but not necessarily unhealthy foods,” said Mielnik. Examples include full-fat dairy products, olive oils, and nut butters, which, she said, can help boost calorie intake without increasing the volume of what patients are eating. 

“With this form of more advanced COPD, not only do patients get very short of breath easily, but when they become too full, that can also cause a lot more shortness of breath, which hinders them from eating enough throughout the day,” Mielnik said. 

The rule of thumb for these patients is to focus on small, frequent meals (eg, every 2-3 hours) that maximize calories with sources of good healthy fats. 

The second type of patient includes at-risk, newly diagnosed, or in the early stages of their disease, often with comorbidities. 

For these patients, “I reiterate that diet cannot cure their COPD but it will help with managing symptoms in general and disease progression. Nutrition also has a huge impact on all these other comorbidities, like type 2 diabetes and heart disease, that can go along with COPD and worsen symptoms,” said Mielnik. 

Separating Apples From Oranges

When it comes to COPD and nutrition, pathophysiology plays a role. 

“Especially for people with obstructive lung disease, their lungs can be a bit hyperinflated at baseline, so they already need more space to breathe,” said Nicole Mills, DO, RD, a pulmonary critical care physician and associate professor of clinical thoracic medicine and surgery, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania. 

This is why certain foods that can produce gas, such as legumes or cruciferous vegetables, or even fizzy drinks, can exacerbate symptoms. 

Mills pointed to the analogy of a pregnant person. “They’re very large, they’re short of breath. When there’s something pushing on the abdomen, whether it's a fetus or gas, it’s harder to breathe.” 

There are also little tricks that can help, even if you are just drinking water, said Arévalo. “If you drink from a straw, for example, you’re going to ‘eat’ a lot more of the air than if you drink from a cup. Simple carbohydrates, simple sugars like desserts and baked goods, can make the body produce more carbon dioxide, so it’s important that patients avoid that as well,” she said. 

Mielnik likewise pointed to the need to counsel patients experiencing increased gas and bloating from fiber to increase fiber in their diet slowly, or to avoid specific gas-forming foods altogether. 

Food for Thought

When it comes to specific foods, there are no hard or fast rules; people react differently depending on how far their disease has progressed, and even time of year. 

“If people are eating less processed foods and eating fresher foods, the type that are available really depends on the time of year,” said Mills. 

It becomes even more complicated when clinicians consider that patients’ symptoms oscillate throughout the year. 

“When it comes to pulmonary disease, diet is not usually the first thing that patients will mention; some people flare more with humidity, some when they are inside with dry heat or dry air. For others, it’s cold weather,” said Mills. “So, patients have different triggers seasonally.” 

Another important consideration is where patients live, which Mills pointed out can affect the availability of fresh fruits and vegetables, especially within the inner cities. 

“I think one of the key messages, especially for a primary care physician, is asking people if they have access to food and if food insecurity is an issue that they are facing,” said Mills. 

It’s also important to ask patients directly if they experience exacerbations of their symptoms after they eat certain foods, 

“We see people at a snapshot in time, like a 20-minute visit, whereas the patient lives with their body,” said Mills. 

When it comes to nutrition, “I think listening and supporting when patients note a correlation is important,” she said. 

Mielnik, Arévalo, and Mills report no relevant financial relationships. 

Han reports personal fees from GlaxoSmithKline, AstraZeneca, Boehringer Ingelheim, Cipla, Chiesi, Novartis, Pulmonx, Teva, Verona, Merck, Mylan, Sanofi, Roche, DevPro, Aerogen, Polarian, Regeneron, Amgen, UpToDate, Altesa Biopharma, Owkin, Medscape, NACE, MDBriefcase, Integrity and Medwiz. She has received either in-kind research support or funds paid to the institution from the NIH, Novartis, Sunovion, Nuvaira, Sanofi, AstraZeneca, Boehringer Ingelheim, Gala Therapeutics, Biodesix, the COPD Foundation, and the American Lung Association. She has participated in Data Safety Monitoring Boards for Novartis and Medtronic with funds paid to the institution. She has received stock options from Meissa Vaccines and Altesa Biopharma. 

Liz Scherer is a health and medical journalist. She frequently covers US, EU, and Canadian news on behalf of Medscape.