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Comparative absorption of [13C]glucose and [13C]lactose by premature infants
R D Murray1, T W Boutton, P D Klein
1Department of Pediatrics, Ohio State University, Columbus.
Insights
Premature infants show varying carbohydrate absorption. Lactose malabsorption and fermentation were higher in younger infants, suggesting maturation improves carbohydrate retention and limits breath test accuracy.
Area of Science:
- Neonatal nutrition
- Gastroenterology
- Metabolic research
Background:
- Premature infants often experience gastrointestinal immaturity, affecting nutrient absorption and metabolism.
- Assessing carbohydrate absorption and oxidation is crucial for optimizing nutritional support in neonates.
- Breath tests using stable isotopes like carbon-13 ([13C]) are non-invasive tools for studying substrate metabolism.
Purpose of the Study:
- To compare the oxidation and fecal recovery of orally administered [13C]glucose and [13C]lactose in two groups of premature infants.
- To investigate the influence of gestational age and postnatal age on carbohydrate malabsorption and fermentation.
- To evaluate the utility of [13C]breath tests for assessing carbohydrate metabolism in premature infants.
Main Methods:
- Oral administration of [13C]glucose and [13C]lactose to premature infants across two study sites (Johns Hopkins Hospital and Columbus Children's Hospital).
- Measurement of fecal recovery of [13C]-labeled substrates to quantify malabsorption.
- Analysis of breath samples to determine the oxidation of administered carbohydrates.
Main Results:
- No significant difference in fecal [13C] loss after [13C]glucose administration between the two infant groups.
- Lactose metabolism showed increased malabsorption and colonic fermentation in the younger infant group (JHH) compared to the older group (CCH), resulting in higher fecal [13C] losses.
- Evidence suggests that intestinal maturation leads to improved proximal absorption and carbohydrate retention.
Conclusions:
- Carbohydrate absorption and fermentation patterns differ in premature infants based on maturation.
- Lactose appears more prone to malabsorption and fermentation than glucose in immature gastrointestinal tracts.
- The simultaneous absorption of substrates from both the small and large intestines may complicate the interpretation of [13C]breath tests in premature infants.
Abstract:
Oxidation of orally administered [13C]glucose and [13C]lactose and fecal recovery of malabsorbed substrates were determined in two groups of premature infants. Eighteen studies were performed with six infants at Johns Hopkins Hospital (JHH); 24 studies were performed with nine infants at Columbus Children's Hospital (CCH). The two groups differed in that JHH infants had shorter gestations but were older when studied. Fecal 13C loss after [13C]glucose administration did not differ between the two groups. Compared with glucose, the metabolism of lactose appeared to involve more malabsorption and colonic fermentation in JHH infants than in CCH infants and resulted in higher fecal losses of substrate carbon. Maturation appeared to involve increased proximal intestinal absorption and greater retention of absorbed carbohydrate. Simultaneous absorption of substrate from the small and large intestine may limit the usefulness of breath tests for 13C in the premature infant.