Oral diet does not alter pulmonary pentane or ethane excretion in healthy subjects

Ethane and pentane are alkanes that are excreted through the lungs to a small degree in healthy subjects. These gasses are produced from the peroxidation of unsaturated fats which are found both in body tissues and in foods. These gasses are excreted in larger amounts by patients with increased production of reactive oxygen metabolites, including those with inflammation or ischemia. Thus, detection of these gasses in excessive quantities is considered evidence for lipid peroxidation. However, the effects of dietary factors on these measurements have not been defined. To define the effects of eating on the pulmonary excretion of these alkanes, 29 healthy subjects were fed a standardized liquid diet (1060 kcal, 12.9 g linoleic acid and 385 mg linolenic acid) after an overnight fast. Breath alkanes were measured at 0, 1, 3, and 6 hours. All subjects had normal vitamin E (1.11 + 0.26 mg/dl), retinol (64 +/- 14 micrograms/dl), beta carotene (27 +/- 21 micrograms/dl), lycopene (23 +/- 12 micrograms/dl) and zinc (81.9 +/- 13.5 micrograms/dl) levels. No statistically significant changes in either alkane were noted relative to the fasting level. We conclude that oral diet does not alter pulmonary ethane or pentane excretion in healthy subjects.