Nutrition and Supplementation in Chronic Lung Diseases

Dietary factors have long been implicated in the cause, prevention and treatment of important diseases and these include chronic lung diseases such as chronic obstructive pulmonary disease (COPD) and asthma.  An adequate diet may be able to inhibit, arrest or even in some cases reverse the effects of lung toxicity.  Several dietary factors have been studied as potential mediators of inflammation, airway smooth muscle, and enzymatic reactions in the lungs.

Antioxodants & Vitamins

Normally the lung exists in an oxygen-rich environment balanced by the toxicity of oxidants and the protective activities of anti-oxidants.  Research has been done in chronic lung disease which hypothesized that a diet low in antioxidants may reduce the natural defense of the lungs against inflammation.  Cigarette smoke and pollutants such as ozone, can induce oxidant damage.  Nutritionally available antioxidants include vitamins E, C and beta-carotene, flavinoids and selenium.  The foods which contain these antioxidants includes broccoli, spinach, carrots, tomatoes, citrus fruits.  Vitamin E is found in oil products.

Vitamin D, in particular has been studied in various chronic lung diseases.  There seems to be an increased prevalence of vitamin D deficiency in patients who suffer with chronic lung disease.  Vitamin D can be obtained both by dietary supplementation or synthesized in skin with sun exposure.  Dietary sources include dairy, fish oil and eggs.

With regard to the development of asthma there has been some research to suggest that asthma may be related to a deficiency of vitamins A, C, D, and E.  Thus asthma may be prevented by supplementation of these nutrients along with a “Mediterranean” diet.  Once a patient develops asthma a healthy diet and exercise is important to the control of the disease.  There is no convincing evidence to show specific supplementation with vitamins will help with asthma control.  It is known that obesity is predictive of poor asthma control.  Gastro-esophageal reflux disease is also a known trigger for asthma attacks thus any foods which cause reflux symptoms should be avoided.  Obesity is also a factor in increased reflux thus having a normal weight is very helpful.

COPD Nutrition

With regard to COPD, it has been long known that malnutrition, weight loss and cachexia (general physical wasting and malnutrition) are associated with a poor prognosis.  This is mainly due to muscle atrophy which may be related to chronic hypoxia (low oxygen level in the blood).  It is known that a person with COPD may require up to 10 times the normal calories.  Thus increased intake of calories especially protein may result in weight gain in COPD patients and improve outcomes.     General recommendations are that patients maintain a BMI of at least 20kg/m2.  This may be done with high calorie and protein supplements.  Appetites stimulants and androgens may also play a role in increasing caloric intake.  Vitamin D has been looked at in underweight COPD patients and supplementation may offer improvement in muscle function.  Also, there are known benefits of vitamin D with regard to the treatment of osteopenia and osteoporosis.  Given that patients with COPD often have these bone related deficiencies secondary to nutritional status and medications used in the treatment of COPD, supplementation with Vitamin D should be considered in every patient.

In Summary

Nutritional health is important for the control of chronic lung diseases.  Mainly maintain a healthy diet rich in antioxidants and a maintaining a normal weight is beneficial in all lung diseases.  In COPD in particular, increased caloric intake is imperative in underweight patients and supplementation with vitamin D may help both muscle and bone function leading to improved quality of life.