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Changes in Small‐Intestine Permeability with Aging
Author(s) -
Saltzman John R.,
Kowdley Kris V.,
Perrone Gayle,
Russell Robert M.
Publication year - 1995
Publication title -
journal of the american geriatrics society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.992
H-Index - 232
eISSN - 1532-5415
pISSN - 0002-8614
DOI - 10.1111/j.1532-5415.1995.tb06382.x
Subject(s) - lactulose , mannitol , medicine , intestinal permeability , creatinine , urine , excretion , gastroenterology , physiology , endocrinology , chemistry , biochemistry
OBJECTIVE: To evaluate small‐intestine mucosal integrity and permeability with advancing age as measured by the lactulose/mannitol absorption test in healthy subjects. DESIGN: Prospective cohort study. SETTING: Clinical research unit of the USDA Human Nutrition Research Center on Aging. STUDY PARTICIPANTS: Fifty‐six subjects were recruited in three age groups: 20 to 39 years (n = 20), 40 to 59 years (n = 19), and ≥60 years (n = 17). Subjects were healthy, community‐dwelling volunteers. INTERVENTION: After an 8‐hour fast, all subjects ingested 10 g of lactulose and 5 g of mannitol. Urine was collected for 6 hours and analyzed for lactulose and mannitol by high performance liquid chromatography. Twenty‐four‐hour urinary creatinine clearances were determined. MAIN OUTCOME MEASURES: Percentages of lactulose and mannitol excreted, the lactulose/mannitol ratio (x100), and the 24‐hour creatinine clearance. RESULTS: With increasing age, both the percentage of lactulose excreted ( P = 0.09) and the percentage of mannitol excreted ( P = 0.05) tended to decrease progressively. The lactulose/mannitol ratio (x100) did not change with increasing age ( P = 0.65) because both the percentages of lactulose and mannitol excreted declined. The creatinine clearance decreased markedly with advancing age ( P < .001) and accounted for the decline in percentages of lactulose and mannitol excreted ( P < .02). CONCLUSIONS: There is a progressive decline in the ability to excrete lactulose and mannitol with increasing age. This is probably attributable to a decline in renal function with advancing age. However, because of parallel decreases in lactulose and mannitol excretion, the lactulose/mannitol ratio does not change. Thus small‐intestine “leakiness” does not increase with aging as measured by the lactulose/mannitol absorption test.