Eating more fiber may lead to healthier lungs

Most people in the United States don't get enough fiber in their diets. Among its many health benefits, fiber can lower the risk of heart disease and stroke, help manage diabetes, and contribute to maintaining a healthy weight. And now, studies increasingly suggest that adequate dietary fiber may help your lungs work better, too.

Fiber and lung function

One such study, published in Annals of the American Thoracic Society in 2016, examined data from more than 1,900 men and women in the National Health and Nutrition Examination Surveys (NHANES). Researchers found that participants who ate the least fiber had worse lung function than those who ate the most. Eating a diet rich in fruits, vegetables, and legumes was associated with increased lung function, though eating whole grains was not.

But other research suggests that whole grains—and particularly cereal grains such as oats, wheat, and barley—are also good for lungs. For example, a European Journal of Nutrition study published in 2020 analyzed data from 1,557 women and found that a diet high in fiber from fruit and cereals (though not from vegetables) reduced the risk of developing chronic obstructive pulmonary disease (COPD). Eating just 16.3 daily grams of fiber from cereals, or the amount found in about 1 1/2 cups of old fashioned oats, made a difference.

Another large study of more than 367,000 people published in BMC Medicine in 2015 suggested that consuming more whole grains was linked to a lower chance of death from respiratory ailments in addition to other causes.

Fiber, inflammation, and gut bacteria

Both the 2016 and 2020 studies suggested that fiber bolsters lung function for two reasons. The first is that fiber helps counter inflammation, a key characteristic of both asthma and COPD. Fiber does this by helping to keep C-reactive protein and IL-6 molecules in check; elevated levels of these proteins in your blood indicate inflammation and have been linked to worsened lung function.

The second way fiber helps has to do with your gut. Eating a sufficient amount of fiber may change the mix of microorganisms that live in your gastrointestinal tract. This could result in more production of short-chain fatty acids (SCFAs), compounds that can help promote a healthy immune system and contribute to the protection of your lungs.

Eat for your lungs

Ask a healthcare provider about how much fiber you should be eating each day. It will depend partly on your age, sex, health status, and other personal factors.

Getting more fiber doesn’t have to mean eating dry wheat bran. A variety of delicious fruits, vegetables, legumes, nuts, and whole grains are packed with it. Good sources include:

• Beans, especially navy beans, which have 19 grams of fiber per 1 cup
• Artichokes
• Peas
• Berries
• Pears
• High-fiber breakfast cereal
• Brown rice
• Quinoa
• Whole-grain pasta and bread

Many fiber-rich foods also deliver a dose of antioxidants, micronutrients that help prevent cell damage and have been shown to improve overall health. For example, citrus fruits, broccoli, and tomatoes are good sources of both fiber and vitamin C, an antioxidant that helps protect lungs from infection.

Some healthy eating plans, such as the DASH Diet and the Mediterranean diet, emphasize fiber, and provide guidelines for including adequate amounts in your everyday meals.

The bottom line

High-fiber, plant-based foods not only add color and variety to your meals, research shows that they may be particularly healthy for your lungs. It can be as simple as swapping your breads, pastas, and cereals for whole-grain versions, and snacking on whole fruits and vegetables instead of more processed foods.