Enzyme replacement therapy for primary adult lactase deficiency. Effective reduction of lactose malabsorption and milk intolerance by direct addition of beta-galactosidase to milk at mealtime

Gastroenterology. 1984 Nov;87(5):1072-82.


The addition of microbial beta-galactosidases directly to milk at mealtime represents a potential "enzyme replacement therapy" for primary lactase deficiency. We used the hydrogen breath test as the index of incomplete carbohydrate absorption to assess the efficacy of two enzymes--one from yeast, Kluyveromyces lactis (LactAid), and the other from the fungus Aspergillus niger (Lactase N)--to assist in the hydrolysis of 18 g of lactose in 360 ml (12 oz) of whole milk when consumed by an adult lactose malabsorber. Graded amounts of Lactase N produced, at best, a 53% relative reduction in breath hydrogen excretion, whereas quantitative elimination of excess hydrogen excretion was produced by 1 and 1.5 g of LactAid. A double-blind, controlled, crossover trial was subsequently performed in 50 healthy, unselected Mexican adults, to whom 360 ml of cow's milk was presented in the three forms in a randomized order: intact milk, prehydrolyzed milk, and milk to which 1 g of LactAid was added immediately before consumption. Among the 25 subjects with incomplete carbohydrate absorption with intact milk, adding enzyme 5-min before consumption produced a 62% reduction in breath hydrogen excretion, and symptoms of intolerance were significantly reduced. The feasibility of effective enzyme replacement therapy with a beta-galactosidase from K. lactis is demonstrated.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Animals
  • Breath Tests
  • Dietary Carbohydrates / metabolism
  • Double-Blind Method
  • Evaluation Studies as Topic
  • Galactosidases / administration & dosage*
  • Humans
  • Hydrogen / analysis
  • Hydrolysis
  • Lactose / metabolism
  • Lactose Intolerance / therapy*
  • Middle Aged
  • Milk*
  • Time Factors
  • beta-Galactosidase / administration & dosage*


  • Dietary Carbohydrates
  • Hydrogen
  • Galactosidases
  • beta-Galactosidase
  • Lactose