Tolerance to lactose among lactase-deficient American Indians

Gastroenterology. 1978 Jan;74(1):44-6.


To determine the amount of lactose that could be tolerated in a meal, 59 lactase-deficient American Indians, ranging in age from 5 to 62, were given graded doses of lactose. The diagnosis of lactase deficiency had beeen documented previously by showing increased breath hydrogen after an oral lactose load (2 g per kg, maximum 50 g). With this load, 88% of the subjects had symptoms. On 6 consecutive mornings, each subject was given a breakfast that contained graded doses of lactose ranging from 0 to 18 g. The order of the breakfasts was randomized and the contents were double-blinded. Symptoms, which were assessed by a "blinded" observer, were present after 9% of the breakfasts at all dosage levels, including the lactose-free breakfast. Thus, under the conditions of this study, a modest amount of lactose, equivalent to that present in 1 to 1 1/2 glasses of milk, when taken with a meal, is well tolerated by the lactase-deficient American Indian.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Child
  • Child, Preschool
  • Clinical Trials as Topic
  • Double-Blind Method
  • Female
  • Humans
  • Indians, North American
  • Lactose Intolerance / diagnosis*
  • Lactose Tolerance Test
  • Male
  • Middle Aged
  • Minnesota