title: 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.
abstract: 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.
mesh_terms: D000328:Adult; D000818:Animals; D001944:Breath Tests; D004040:Dietary Carbohydrates / Q000378:metabolism; D004311:Double-Blind Method; D005069:Evaluation Studies as Topic; D005696:Galactosidases / Q000008:administration & dosage*; D006801:Humans; D006859:Hydrogen / Q000032:analysis; D006868:Hydrolysis; D007785:Lactose / Q000378:metabolism; D007787:Lactose Intolerance / Q000628:therapy*; D008875:Middle Aged; D008892:Milk; D013997:Time Factors; D001616:beta-Galactosidase / Q000008:administration & dosage*
chemical_list: D004040:Dietary Carbohydrates; D006859:Hydrogen; D005696:Galactosidases; D001616:beta-Galactosidase; D007785:Lactose