Breathing involves the diaphragm and intercostal muscles, which expand the chest to create a vacuum that draws air into the lungs, where oxygen diffuses into the blood through the alveoli and binds to hemoglobin. Carbon dioxide produced by cells is then expelled from the bloodstream and exhaled.

Various diseases can affect breathing and respiration by affecting different lung tissues or the chest wall, and causes range from environmental to congenital. These causes include airway diseases like asthma and COPD, alveolar diseases such as pneumonia and tuberculosis, vascular issues like pulmonary embolism, interstitial diseases, pleural conditions, and musculoskeletal disorders.

Diet influences the development and management of respiratory diseases, particularly in conditions like COPD and asthma, and high fruit and vegetable intake, a Mediterranean diet, and omega-3 fatty acids show benefits. Conversely, Western and fast food diets are associated with negative outcomes in respiratory health.

Supplements of interest for lung diseases include vitamin D; antioxidants such as vitamin C, vitamin E, flavonoids, and lycopene; and anti-inflammatory agents like curcumin. Additionally, N-acetyl cysteine is beneficial for people with COPD due to its mucus-reducing properties and is important in managing cystic fibrosis.