A significant percentage of people with COPD are underweight and considered malnourished. For many of these COPD patients, the main reason for the malnutrition stems from a higher than normal metabolism due to the need for their bodies to work harder to generate each breath (even at rest) compared to people with healthy lung function. Additionally, the act of eating food is more demanding and less satisfying for many people with COPD due to difficulty in swallowing, persistent coughing, chronic sputum secretion, and general shortness of breath.
As a result, many underweight COPD patients have suppressed appetites and eat less food than their bodies’ need to meet the heightened energy requirements to simply keep breathing. By eating less food, underweight/malnourished COPD patients also have less energy and therefore are more sedentary. Being sedentary leads in turn to a condition known as muscle wasting where the combination of low nutrient intake and lack of exercise/movement causes the body’s muscles to become weak and dysfunctional.
In past COPD nutrition studies, researchers have sought to test different ways of delivering calorie rich foods and nutritional supplements to help patients add weight, build lean muscle, boost energy, and increase exercise capacity. The results of these studies have been mixed.
A new study published in June 2010 in the journal Respiratory Medicine took a fresh look at this problem and proposed a new solution – combine nutritional supplementation with a low intensity pulmonary rehabilitation exercise program. The study team speculated that nutritional supplementation alone is not sufficient to produce desired conditioning benefits because the body also needs an anabolic stimulus (exercise) to build muscle mass and improve physiologic function.
In the study, a group of Japanese researchers enrolled 32 moderate to severe COPD patients. The patients were divided into two groups. The control group of 15 patients did not receive nutritional supplementation and did not participate in an outpatient pulmonary rehab program. The nutrition/exercise group consisted of 17 patients who underwent a 12 week program of low intensity exercise and oral nutritional supplementation. This group also received other core elements of pulmonary rehabilitation such as breathing training and counseling/education on other aspects of COPD disease management.
The nutritional supplementation provided to the nutrition/exercise group consisted of two 200ml packages of a nutritional drink each day that contained 60% carbohydrates, 25% fat, and 15% protein. The nutrition drink provided an extra 400 calories per day, and included Omega-3 polyunsaturated fatty acids and vitamins (the study does not describe what specific vitamins were supplemented but does indicate that the vitamins incorporated in the drink were primarily antioxidants).
The daily nutrition/exercise group exercise training consisted of 15 minutes of walking, strength training exercises for both upper and lower body, calisthenics and respiratory muscle stretching. The intensity level targeted for these exercises was 40-50% of maximum oxygen consumption (a measure of peak oxygen usage for each patient, established at the outset of the program). At this level, the exercise was considered low intensity.
One interesting note is the nutrition/exercise group only trained in the outpatient pulmonary rehab center one day every two weeks of the 12 week study. The rest of their training was supposed to take place unsupervised at home – which is putting a lot of faith in the exercise compliance of the nutrition/exercise group.
The researchers found that the nutrition/exercise group experienced significant increases from the beginning of the program to the end of the program (as compared to the control group) in quadriceps muscle force, walking endurance, body weight, weight bearing capability, and self-reported health status. For example, the nutrition/exercise group’s mean quadriceps muscle force rose 21% over the course the 12 week program while the control group’s quadriceps force declined by 3%. The nutrition/exercise group’s mean performance on the 6 minute walk test (a measure of walking endurance) improved 6% while the control group declined by 11%. The mean ability to bear weight rose by 15% for the nutrition/exercise group but remained flat for the control group.
Separately, the researchers also measured whether the combination of nutritional supplementation and low intensity exercise reduced airway inflammation in the nutrition/exercise group of COPD patients. The study results demonstrated that the combination of exercise and nutrition supplementation did in fact reduce counts of proteins known as “cytokines” that are general indicators of the presence of tissue inflammation.
In response to inflammation, cytokines are released by cells in the lining of the lungs and signal the body to react to suppress the inflammation. A high cytokine count is indicative of significant inflammation and vice versa. Over the 12 week program, the nutrition/exercise group saw mean cytokine counts for the three types of cytokines evaluated (interleukin-6, interleukin-8, and Tumor Necrosis Factor-alpha) drop 10%, 45% and 22% respectively. By contrast, the control group cytokine counts for these types rose 44%, 58% and 24% respectively. These are significant differences and clearly demonstrate the effectiveness of the nutrition/exercise intervention.
The research team concluded, “our data suggest a potential role for the combination of nutritional support and low-intensity exercise, and that this combination may improve the outcomes of exercise tolerance and health-related QOL (quality of life) in patients with malnourished COPD. Thus a combination of nutritional support and low-intensity exercise may provide a new therapeutic approach for pulmonary cachexia (muscle wasting).”
No comments:
Post a Comment