Though it primarily affects the lungs, the first line of defence against chronic obstructive pulmonary disease (COPD) besides smoking cessation and medication is diet. This, in part, is because the disease is often accompanied by malnutrition, loss of weight or extreme overweight – all of which significantly impair breathing.
Smokers’ and COPD patients’ disease outcome is highly determined by nutritional status (BMI), body composition (body fat and muscle mass ratio) and fat-free mass (FFM), irrespective of respiratory function”
, says János Varga, associate professor at Semmelweis University’s Department of Pulmonology, corresponding author of the studies.
The researchers have analyzed the data of more than 45,000 people with COPD (smokers and non-smokers, including control groups) between 2018 and 2023. Their findings confirm that
a diet rich in proteins (1.2-1.5 g/kg of body weight) with a lower ratio of carbs (40%-45%), and a higher percentage of healthy fats (35%-40%) can slow down disease progression and alleviate symptoms.
Higher protein intake helps preserve bone and muscle mass against osteoporosis and sarcopenia, which are two common side effects of COPD, associated with an increased mortality risk. A lower carbohydrate ratio is important because of all three macronutrients carbs have the highest respiratory quotient – the amount of carbon dioxide produced for oxygen intake.
Swapping a part of carbs for healthy fats results in less CO2 produced for the same calorie amount.
Since patients with severe COPD already have difficulty breathing due to impaired airflow and weaker respiratory muscles, a lower amount CO2 produced will ease respiration
, Varga notes.
The researchers also advise to reduce the consumption of red and processed meats and meat products (pickled, salted, and smoked meats, bacon, and processed and semi-prepared industrial products e.g., sausages). Besides nitrites and sodium, these meats contain high levels of saturated fatty acids, which can further exacerbate inflammation in the airways and impair respiratory function.
Since quitting smoking may not stop the disease from exacerbating, diet has an even more vital role in slowing its progression.
Through diet alone – Mediterranean-style diet with increased protein intake, antioxidant-rich foods, especially fresh fruits and vegetables, omega-3 fatty acids – patients can normalize their weight, reduce inflammation and, as a result, cut the need for steroids. Overall, their quality of life improves
, says Mónika Fekete of the Department of Public Health, Faculty of Medicine, Semmelweis University, first author of the studies. Drinking at least two liters of fluids per day (water, tea, juice) is also important, she adds.
Alongside diet, the Semmelweis researchers recommend daily consumption of 0.4-2 g/day Vitamin C, a minimum of 500 mg/day of omega-3 fatty acids (up to 2000 mg/day or twice weekly fatty fish) and 300-500 mg/day of magnesium, 1200-1500 mg/day calcium for people with COPD.
Tobacco smoke – both active and passive – is known to limit Vitamin D effectiveness which has a vital role in curbing exacerbations. COPD being a chronic disease of high risk, the recommended daily dose for Vitamin D is 50 µg (2000 IU) provided blood serum levels are priorly checked, Fekete says.
COPD is characterized by a low-level, systemic inflammation and an excess of harmful oxidants. A diet rich in antioxidants including Coenzyme Q10, resveratrol and quercetin, positively influences the levels of inflammatory markers.
Black seed oil in particular positively affected on various aspects of COPD including respiratory function, airway inflammation and oxidative–antioxidant status.
Diet and supplementation bring the best results when linked with rehabilitation. This includes steady state cardio training, physiotherapy, breathing techniques, etc. “These will not only lead to an increase in muscle mass and stamina but an improved breathing mechanism as well as weakened respiratory muscles become stronger”, Varga highlights. “Overall, breathing becomes easier.”
In general, it takes 8 weeks for people to notice positive changes but some of the benefits can be seen as early as 3 weeks upon applying the recommended dietary changes, he adds.
Chronic obstructive pulmonary disease (COPD) refers to a group of diseases that cause airflow blockage and breathing-related problems. By 2020, COPD became the third leading cause of death worldwide, caused mostly by smoking (85-90%) in high-income countries. Household air pollution is also a major risk factor. Severe COPD develops in 15–20% of chronic smokers. Current pharmacotherapy provides symptomatic relief, but has limited impact on COPD progression. While its prevalence is widespread with high mortality, COPD is a preventable and treatable condition.
Credit: WHO, Semmelweis University