Word: digest
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Dates: during 1970-1979
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...evil spirits. Colombian Indians refuse to drink reconstituted milk and use it instead to paint their huts. On the Navajo reservation, many Indians discard Government-issue powdered milk rather than suffer diarrhea. All have a problem in common. A surprisingly large portion of the world's population cannot digest an important ingredient in milk: lactose...
Response to a Challenge. Why can virtually all infants and many adults digest lactose, while other adults cannot? One theory is that the ability to produce lactase, and thus to digest lactose, is the response to a challenge: if a person continues to drink milk after he has been weaned and through adulthood, he will always be able to digest it. But if he goes without milk for months or years, he loses that ability...
That theory is disputed by many investigators, most recently U.C.L.A. Anthropologist Robert McCracken. He believes that the ability to secrete lactase and digest lactose is determined in the genes. Virtually all normal mammals have a gene that turns on the supply before birth, maintains it at a high level until weaning, and then allows it to decline. When man first emerged as Homo sapiens, says McCracken, and for tens of thousands of years thereafter, he was a hunter and gatherer of food. He had no milk cattle. A baby was usually weaned by the age of two. Nature designed milk...
...indigenous populations of West Africa have low lactase levels and high intolerance-as have 75% of most U.S. Negro groups tested; the highest rate reported among most whites is only about 19%. High proportions of American Indians, in the U.S. and Central and South America, are also unable to digest milk...
Enzymes are aptly called the mediators of life. Without these essential proteins, vital chemical reactions would occur far too slowly, if at all. Living things could not grow, digest food, store energy, transmit messages across nerve cells or reproduce. Like laboratory or industrial catalysts, enzymes trigger and speed up chemical reactions without themselves being affected or altered by them. But enzymes can cause these reactions to take place up to a billion times faster than catalysts used in the laboratory or chemical plant...