Eighty patients (mean age, 63 years) with chronic obstructive pulmonary disease (COPD) were randomly assigned to receive, in double-blind fashion, 9 g/day of polyunsaturated fatty acids (PUFAs) (providing daily 760 mg of gamma-linolenic acid, 1,200 mg of alpha-linolenic acid, 700 mg of eicosapentaenoic acid, and 340 mg of docosahexaenoic acid) or placebo (80% palm oil and 20% sunflower oil) during an 8-week rehabilitation program. All capsules contained 3.5 mg/g of vitamin E. Both groups had similar increases in body weight, fat-free mass (FFM), and muscle strength. The peak load of the incremental exercise test increased more in the PUFA group than in the placebo group (p = 0.009), even after adjustment for FFM. The duration of the constant work rate test also increased more in patients receiving PUFA (p = 0.023). The positive effects of PUFA could not be attributed to a decrease in systemic levels of CRP, IL-6 and TNF-alpha.

Comment: These results suggest that supplementation with a mixture of fatty acids improved exercise capacity in patients with COPD. Although some of these fatty acids have been shown to have anti-inflammatory effects, the clinical improvement in this study did not seem to be due to a reduction in inflammation.

Patients with COPD are frequently malnourished, or become malnourished as a result of increased metabolic demands related to the disease. Malnutrition in patients with COPD can decrease respiratory-muscle and lung function, and reduce defense mechanisms in the lungs. A comprehensive nutritional program that includes protein, calories, vitamins, and minerals may improve the clinical status of patients with COPD. The results of the present study indicate that essential fatty acids are also important for people with chronic lung disease.

Broekhuizen R, et al. Polyunsaturated fatty acids improve exercise capacity in chronic obstructive pulmonary disease. Thorax 2005;60:376-382.