Acute effects of different nutritional supplements on symptoms and functional capacity in patients with chronic obstructive pulmonary disease

Background: Use of nutritional supplements in depleted patients with chroni c obstructive pulmonary disease (COPD) requires optimization between positi ve effects on outcome and potential acute adverse effects on metabolism and exercise performance. Objective: The aim of this study was to investigate the acute effects of nu tritional supplements on metabolism and exercise capacity in stable COPD pa tients. Design: In part 1, the effects of 3 different energy loads (placebo, 1046 k J, and 2092 kJ) with a normal distribution of macronutrients were investiga ted in 14 COPD patients. In part 2, the effects of a fat-rich compared with a carbohydrate-rich supplement (both 1046 kJ) were studied in 11 COPD pati ents. The study was performed in a randomized, double-blind, crossover fash ion. Metabolic and ventilatory variables were measured postprandially and d uring a submaximal cycle endurance exercise test. Results: Overall, no immediate negative effects of the supplements were fou nd in part 1. A slight but significant postprandial increase in respiratory quotient was found after the 1036-kJ and 2092-kJ supplements compared with placebo. There was no significant difference in metabolism or exercise cap acity after a fat-rich or carbohydrate-rich supplement. Surprisingly, the c hange in shortness of breath (postprandial compared with preprandial) was s ignificantly greater after the fat-rich supplement. Conclusions: An energy load up to 2092 kJ had no adverse immediate effect i n COPD patients compared with placebo. The subjects who consumed the fat-ri ch supplement experienced more shortness of breath than did the subjects wh o consumed the carbohydrate-rich supplement.