Abstract
Small amounts of lactose have been shown to be absorbed intact across the intestine and excreted unchanged in the urine of newborns and adults. We designed a study to quantitate the intestinal uptake and urinary excretion of this disaccharide in these age groups. Similar amounts of lactose were given orally to 17 term newborns (age: 24.8 ± 3.0 h) as a standard infant formula, and to 15 adult lactose absorbers (age: 28.1 ± 2.6 years) and 11 adult lactose malabsorbers (age: 24.7 ± 2.9 years) as a 20% water solution. Following lactose ingestion, breath was collected every 30 or 60 min for 3 h and analyzed for hydrogen concentration. Urine was also collected, and lactose and creatinine concentrations were determined. Peak hydrogen concentration was <20 ppm above baseline in newborns and adult lactose absorbers and 85 ± 14 ppm in adult lactose malabsorbers. Urinary lactose excretion, expressed as a function of body weight (mg/ml/kg b.w.), was substantially greater in newborns (4.2 ± 0.82) than in adult lactose absorbers (0.29 ± 0.07; p < 0.001) and adult lactose malabsorbers (0.55 ± 0.04: P < 0.01). Similarly, urinary lactose excretion expressed as a ratio of urinary lactose to urinary creatinine (mg/mg) was increased (p < 0.001) in newborns (2.05 ± 0.26) when compared to adult lactose absorbers (0.11 ± 0.02) and adult lactose malabsorbers (0.20 ± 0.02). Our data demonstrate that the intestinal uptake and urinary excretion of intact lactose is significantly increased in newborns compared to adult subjects.
Original language | English (US) |
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Pages (from-to) | 334-342 |
Number of pages | 9 |
Journal | Neonatology |
Volume | 58 |
Issue number | 6 |
DOIs | |
State | Published - 1990 |
Externally published | Yes |
Keywords
- Infants
- Lactose absorption
- Urine lactose
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health
- Developmental Biology