Absorption of short-chain fatty acids from the human colon measured by the 14CO2 breath test.
The absorption and metabolism of short-chain fatty acids (SCFAs) have been studied in 31 patients. Physiological amounts (7.5 mmol) of (1-14C)-labeled acetic, propionic, and butyric acid and (2-14C)-labeled propionic acid were instilled into the cecum and ascending part of the colon during colonoscopy, and the metabolism of acids to CO2 was measured for 24 h by the 14CO2 breath test. During the first 6 h the cumulative output of 14CO2 from the (1-14C)-labeled acetic, propionic, and butyric acids were (median and range) 50% (46%-56%), 50% (43%-56%), and 63% (58%-73%) and during 24 h 55% (50%-63%), 58% (46%-60%), and 70% (63%-83%), respectively, of the instilled dose. The elimination patterns of the (1-14C)-labeled acids were rather similar, although butyric acid was eliminated to a somewhat greater extent than acetic and propionic acid (p less than or equal to 0.01). (2-14C)-labeled propionic acid was eliminated more slowly than (1-14C)-labeled propionic acid, with a cumulative output of 37% (30%-39%) after 6 h (p less than 0.01), but reached the same value after 24 h, 54% (47%-60%). In agreement with findings in other species, humans have a great capacity for uptake and metabolism of SCFAs formed in the colon.
D000085:Acetates / Q000008:administration & dosage / Q000378:metabolism*; D000328:Adult; D000368:Aged; D001944:Breath Tests; D002087:Butyrates / Q000008:administration & dosage / Q000378:metabolism*; D002245:Carbon Dioxide; D003106:Colon / Q000378:metabolism*; D003113:Colonoscopy; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D008875:Middle Aged; D011422:Propionates / Q000008:administration & dosage / Q000378:metabolism*
D000085:Acetates; D002087:Butyrates; D011422:Propionates; D002245:Carbon Dioxide