Lung Health
As outlined in the Cancer section of this website, fruits, such as pears, may be protective against lung cancer. But what about protective benefits against other lung illnesses, such a chronic obstructive pulmonary disease (COPD)? The National Center for Health Statistics reports that COPD is the fourth leading cause of death in the United States (1). It is a set of progressive, inflammatory diseases characterized by a limitation in airflow that makes it very difficult to breathe. COPD includes chronic obstructive bronchitis and emphysema, and produces large amounts of mucous, wheezing, shortness of breath, chest tightness, severe fatigue, and other symptoms. Depending on the severity of the illness, COPD can be physically disabling and lead to death. Like lung cancer, smoking tobacco is the leading cause of COPD (2).
When we inhale, air travels down the trachea, into the bronchial tubes of the lungs, and end in alveoli (air sacs). The lungs look a lot like an upside down tree: the trachea is the trunk, the bronchial tubes are the branches, and the alveoli are the leaves. The alveoli are small, robust bulbs that act like tiny balloons; as air enters, the sacs fill with air and pull oxygen from the air into the bloodstream. As we exhale, the sacs deflate and release mostly carbon dioxide back into the atmosphere. Oxygen is transported throughout the body to sustain life, and this gas exchange is where COPD strikes the hardest.
In COPD, gas exchange is hampered because the airways and air sacs lose their elasticity, alveolar walls are destroyed or become very thick and swollen, or the airways produce too much mucous which blocks air transport. In a patient who has emphysema, the alveolar walls become very damaged, lose their elasticity, and look like deflated balloons. Sometimes the damage to the air sac walls is so profuse, that many are destroyed. This leaves fewer alveoli that struggle to exchange gases. In patients suffering from chronic obstructive bronchitis, the airways become very irritated and swollen. When the alveoli swell, the mucous lining also swells and thickens, filling the air sacs with mucous. Since the air sacs are full of mucous, it is difficult to force air into them to exchange gas. Most COPD patients have symptoms of both emphysema and chronic bronchitis (2). Interested in learning more about COPD? Visit the American Lung Association website at http://www.lungusa.org.
At this time, there is no known way to reverse lung damage caused by COPD, but never smoking or quitting smoking is the best practice to prevent COPD (2). However, several studies listed below suggest that intake of fruits, antioxidants, and fiber may have beneficial effects on respiratory diseases. This is good news for pear fans, because pears are a good source of the antioxidant vitamin, vitamin C, contain other antioxidants, and are an excellent source of fiber! In addition to cancer fighting agents, read on to learn how pears contain protective agents against other respiratory illnesses, such as COPD.
1. Centers for Disease Control and Prevention: National Center for Health Statistics, Faststats. Available online here.
2. American Lung Association, Chronic Obstructive Pulmonary Disease (COPD) Fact Sheet. Available online here.
Findings
Fiber from fruit fights lung disease!
Exposure to tobacco-smoke as a child has harmful effects on respiratory function and long-term effects on adult respiratory health. In a study of 35,000 non-smokers in Singapore who had lived with a smoker during childhood, dietary fiber from fruit was found to be a major protective factor against adult respiratory symptoms! Study participants who ate more than 7.5 grams of fiber daily had fewer health effects. In fact, those who ate even small amounts of fruit fiber had less chronic cough related to environmental tobacco smoke. Dietary fiber may have beneficial effects on the lung by reducing blood glucose concentrations, reducing inflammation, and enhancing antioxidant processes. Higher fiber intake may create a state of reduced inflammation and reduced oxidative stress, protecting the lung against respiratory symptoms. Also, these data suggest that poor dietary intake of fruit or fruit fiber may accentuate the harmful effects of early exposure to tobacco-smoke.
David GL, Koh WP, Lee HP, Yu MC, London SJ. Childhood exposure to environmental tobacco smoke and chronic respiratory symptoms in non-smoking adults: The Singapore Chinese Health Study. Thorax 2005;60:1052–1058.
A study of 15,792 men and women aged 44 to 66 years, found a healthy association between improved lung function and increased fiber and fruit intake! Both airway inflammation and oxidative stress are thought to be causative factors in the development of chronic bronchitis, emphysema, and deterioration of lung function. This study found that increasing dietary fiber may reduce inflammation, and the antioxidant properties of fiber and fruit may prevent oxidative damage leading to lung illness. Fiber intake has been noted to reduce levels of C-reactive protein (CRP), a general marker of inflammation, which corroborates these findings. It was also noted that replacing the intake of foods that may have detrimental effects on health (processed foods, etc.) with foods high in dietary fiber such as fruit, may have contributed to the reduced risk for lung illness! Overall, a higher dietary intake of fiber, including from fruits, was associated with improved lung function and reduced prevalence of COPD. By including more pears in your diet, which contain about 24% of your daily fiber needs each, you get a healthy dose of fiber and antioxidants which may help fight COPD!
Kan H, Steven J, Heiss G, Rose KM, London SJ. Dietary fiber, lung function, and chronic obstructive pulmonary disease in the Atherosclerosis Risk in Communities (ARIC) Study. American Journal of Epidemiology 2008;167(5):570-578.
This site is for informational purposes only, and is not intended to treat any illness or condition. If you have questions or concerns about your health, seek advice from your physician.