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Passive and active carbohydrate absorption by the ageing gut
D M Beaumont1, I Cobden, W L Sheldon
1Department of Clinical Biochemistry, University of Newcastle Upon Tyne.
Age and Ageing
|September 1, 1987
Summary
Advanced age and malnutrition do not impair passive carbohydrate absorption. However, active sugar transport may be affected in healthy elderly individuals, warranting further investigation.
Area of Science:
- Gastroenterology
- Human Physiology
- Nutritional Science
Background:
- Age-related changes can affect nutrient absorption.
- Hospitalization and malnutrition are common in the elderly and may impact physiological functions.
Purpose of the Study:
- To investigate the effects of advanced age, hospitalization, and malnutrition on passive and active carbohydrate absorption.
- To assess carbohydrate absorption using specific probe molecules in different subject groups.
Main Methods:
- Five subject groups were studied: young, middle-aged, and elderly healthy controls, long-stay hospital patients, and elderly patients with malnutrition.
- Subjects ingested a drink containing lactulose, mannitol (passive absorption markers), and 3-O-methylglucose (active absorption marker) in isotonic and hypertonic solutions.
- Urinary recovery of probe molecules was measured, and results were corrected for renal function using creatinine clearance.
Main Results:
- Urinary recovery of all probe molecules decreased significantly with age and was lower in malnourished elderly subjects.
- After correction for renal function, no significant differences in passive carbohydrate absorption were found between groups.
- A reduced ratio of 3-O-methylglucose to mannitol recovery was observed in healthy elderly subjects under hypertonic conditions, suggesting potential active transport impairment.
Conclusions:
- Passive carbohydrate absorption remains intact in healthy elderly individuals and hospital patients, irrespective of age or nutritional status.
- Active carbohydrate transport may be impaired in healthy elderly individuals, particularly under hypertonic conditions, though this requires further confirmation.
- Hospitalization and malnutrition did not reveal significant impairments in passive or active carbohydrate absorption in the elderly patients studied.