THE EFFECTS OF HIGH-FAT AND HIGH-CARBOHYDRATE DIET LOADS ON GAS-EXCHANGE AND VENTILATION IN COPD PATIENTS AND NORMAL SUBJECTS

Reducing the CO2 production (VCO2) is a plausible means to lower the v entilatory demand in the treatment of patients with COPD. The purpose of this study was to examine the effects of high-fat and high-carbohyd rate (high-CHO) diet loads on gas exchange and ventilation in the COPD patients and normal subjects. The percentage of changes in the averag ed values of VCO2, O2 consumption (VO2), respiratory quotient (RQ), mi nute ventilation (VE), and end-tidal CO2 (ETCO2) measured by a mass sp ectrometer for 5 min every 30 min after the diet were compared between diets and between study subjects. Compared with the high-fat diet, th e high-CHO diet can lead to significantly higher levels of VCO2, VO2, RQ, and VE in the COPD patients 30 to 60 min after the diet, and the d ifferences can last for about 1.5 b. The comparison between COPD patie nts and normal control subjects also showed that the high-CHO diet loa d can result in significantly higher levels of VCO2, VO2, and VE, and significantly lower level Of ETCO2 in the COPD patients, whereas the h igh-fat diet cannot. In addition, enhanced thermic effect of food with in 150 min (TEF150) occurred in the COPD patients as compared with tha t of normal controls, and the increase in TEF150 occurred only with th e high-CHO diet. This study suggested that a high-fat diet is more ben eficial to the COPD patient than a high-CHO diet, and that the gas exc hange and energy utilization of the COPD patients following a high-CHO diet might be different from that of normal control subjects.