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Measuring Lactase Enzymatic Activity in the Teaching Lab
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Measuring Lactase Enzymatic Activity in the Teaching Lab

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Effects of malnutrition on expression and activity of lactase in children

B L Nichols1, M A Dudley, V N Nichols

  • 1United States Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA.

Gastroenterology
|March 1, 1997
PubMed

Insights

Malnourished infants often have low lactase activity due to suppressed lactase gene expression or reduced mRNA stability. This study investigated the transcriptional regulation of lactase in infant malnutrition.

Area of Science:

  • Pediatric Gastroenterology
  • Molecular Nutrition
  • Infant Metabolism

Background:

  • Malnourished infants frequently exhibit reduced lactase specific activity in the small intestine.
  • Hypolactasia in infants is a significant concern impacting nutrient absorption.

Purpose of the Study:

  • To test the hypothesis that hypolactasia in malnourished infants stems from suppressed lactase gene expression.
  • To investigate the molecular mechanisms underlying reduced lactase activity in infant malnutrition.

Main Methods:

  • Analysis of biopsy specimens from 29 malnourished infants and 10 healthy controls.
  • Quantification of lactase and sucrase messenger RNA (mRNA) levels.
  • Assessment of lactase and sucrase enzyme proteins and activities.

Main Results:

  • Lactase mRNA was significantly reduced to 32% and sucrase mRNA to 61% in malnourished infants compared to controls.
  • Lower lactase and sucrase enzyme proteins and activities were observed in malnourished infants.
  • Partial villus atrophy was present in malnourished infants; adult hypolactasia genotype was absent.

Conclusions:

  • Malnutrition suppresses lactase gene transcription or mRNA stability in infants, distinct from adult genetic hypolactasia.
  • The observed reduction in lactase mRNA abundance is greater than that of sucrase mRNA, suggesting specific regulatory mechanisms.
  • These findings explain the common occurrence of low lactase activity in malnourished infants.
Abstract

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