Limonene in expired lung air of patients with liver disease

As part of an effort to examine the relationship between chemosensory disturbance and oral chemistry, we analyzed expired lung air samples from a series of 24 patients with liver disease and 24 healthy controls using gas chromatography-mass spectrometry. Compared to samples from controls, lung air from patients with liver disease contained unusually high levels of limonene, a monoterpene that is a major component of the essential oil of citrus fruits (0.1 vs 7.0 micrograms/20 liters for controls and patients). Only half the patients showed high levels of limonene. Patients with noncholestatic liver disease were significantly more likely to have elevated lung air limonene levels than those with cholestatic liver disease (0.2 vs 13.8 micrograms/20 liters). Responses to food frequency and dietary behavior questionnaires indicated a pattern of diet selection and food preferences that were consistent with a dietary origin for the limonene in these patients.