Yogurt--an autodigesting source of lactose

N Engl J Med. 1984 Jan 5;310(1):1-3. doi: 10.1056/NEJM198401053100101.


Large quantities of yogurt are consumed by some lactase-deficient population groups. We used breath hydrogen measurements to determine whether lactase-deficient subjects absorbed lactose in yogurt better than lactose in milk. Ingestion of 18 g of lactose in yogurt resulted in only about one third as much hydrogen excretion as a similar load of lactose in milk or water, indicating a much better absorption of lactose in yogurt. Ingestion of yogurt also resulted in fewer reports of diarrhea or flatulence than did a similar quantity of lactose ingested in milk or a water solution. The enhanced absorption of lactose in yogurt appeared to result from the intraintestinal digestion of lactose by lactase released from the yogurt organisms. This autodigesting feature makes yogurt a well-tolerated source of milk for lactase-deficient persons and may explain the widespread consumption of yogurt by lactase-deficient population groups.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Breath Tests
  • Dairy Products* / analysis
  • Humans
  • Hydrogen / analysis
  • Intestinal Absorption
  • Lactose / metabolism*
  • Lactose Intolerance / metabolism
  • Yogurt* / analysis
  • beta-Galactosidase / metabolism


  • Hydrogen
  • beta-Galactosidase
  • Lactose