Biomaterial Database

Lactase deficiency: a common genetic trait of the American Indian. 1977

A D Newcomer, and P J Thomas, and D B McGill, and A F Hofmann

Intestinal lactase activity was assessed indirectly in 156 American Indians by measuring breath hydrogen after an oral lactose load. Lactase deficiency was present in 66% of subjects and correlated highly with the percentage of Indian blood. Lactase deficiency was present by the age of 5 years and was unrelated to sex. Most lactase-deficient subjects (81%), but only a minority (23%) of lactase-sufficient subjects, developed symptoms after the oral lactose load, and among lactase-deficient subjects, symptoms occurred more frequently in adults than in children (P = 0.05). Indeed, by history, 53% of lactase-deficient adults, but only 10% of lactase-deficient children under 18 years of age, were aware of milk intolerance. Despite these differences, milk consumption was only slightly less (19 g) in the lactase-deficient subjects than in those with normal lactase activity (25 g) (P less than 0.05). The results indicate that lactase deficiency is a common autosomal genetic trait in the American Indian that becomes manifest in early childhood. Tolerance to dietary lactose appears to decline in the American Indian as he reaches adulthood, but in this population the decline in tolerance had only minor influence on lactose intake.

UI	MeSH Term	Description	Entries
D007198	Indians, North American	Members of indigenous North American populations with pre-colonial contact origins.	Amerinds, North American,Indigenous North Americans,American Indian, North,American, Indigenous North,Amerind, North American,Indian, North American,Indigenous North American,North American Amerind,North American Amerinds,North American Indian,North American Indians,North American, Indigenous
D007785	Lactose	A disaccharide of GLUCOSE and GALACTOSE in human and cow milk. It is used in pharmacy for tablets, in medicine as a nutrient, and in industry.	Anhydrous Lactose,Lactose, Anhydrous
D007787	Lactose Intolerance	The condition resulting from the absence or deficiency of LACTASE in the MUCOSA cells of the GASTROINTESTINAL TRACT, and the inability to break down LACTOSE in milk for ABSORPTION. Bacterial fermentation of the unabsorbed lactose leads to symptoms that range from a mild indigestion (DYSPEPSIA) to severe DIARRHEA. Lactose intolerance may be an inborn error or acquired.	Lactose Malabsorption,Alactasia,Dairy Product Intolerance,Hypolactasia,Milk Sugar Intolerance,Intolerance, Lactose,Malabsorption, Lactose
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D008892	Milk	The off-white liquid secreted by the mammary glands of humans and other mammals. It contains proteins, sugar, lipids, vitamins, and minerals.	Cow Milk,Cow's Milk,Milk, Cow,Milk, Cow's
D008910	Minnesota	State bordered on the north by Canada, on the east by Lake Superior and Wisconsin, on the south by Iowa, and on the west by North Dakota and South Dakota.
D002648	Child	A person 6 to 12 years of age. An individual 2 to 5 years old is CHILD, PRESCHOOL.	Children
D002675	Child, Preschool	A child between the ages of 2 and 5.	Children, Preschool,Preschool Child,Preschool Children
D004032	Diet	Regular course of eating and drinking adopted by a person or animal.	Diets