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Lactose Intolerance: Overview

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People with lactose intolerance have trouble digesting lactose, the natural sugar found in milk and milk products. Undigested lactose can upset the stomach and cause diarrhea. Most people who are lactose intolerant are able to consume some lactose without symptoms. However, many people who are (or think they are) lactose intolerant avoid dairy products and do not consume enough calcium and vitamin D, which are nutrients critical to bone growth and development. NICHD scientists aim to understand the effect of inadequate nutrient intake, due to real or perceived lactose intolerance, on bone growth as part of a broader objective of identifying factors in childhood and youth that promote lifelong bone health and prevent osteoporosis in later life. 

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Common Name

  • Lactose intolerance

Medical or Scientific Name

  • Lactose malabsorption
  • Adult-type hypolactasia
  • Lactase nonpersistence
  • Hereditary lactase deficiency
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