Americans Told to Get Primitive
Scientists look to Stone Age for tips on child care, nutrition
The San Francisco Chronicle - February 16, 1993, front page
By Charles Petit
Chronicle Science Writer
We all might be a lot better off if we got back to some Stone Age habits, including how we raise our babies and how we eat, scientists said here yesterday.
It may not mean trading in a television for smoke signals and jungle drums, or swapping a condo for a cave, but it might mean a whole lot more grain and vegetables and far less red meat. And parents might have to sleep with their babies for many months rather than put them in cribs.
The idea, fostered by a growing cadre of researchers from many fields, is that people are unchanged genetically from ancestors who lived by hunting and gathering in small tribal groups and that a lot of human ailments stem from "mal-adaptation" to modern, industrial society.
"Our bodies are in environments for which they are not evolutionarily prepared," said Dr. Randolph Nesse, a psychiatrist and human biologist at the University of Michigan Medical School. He took part in a session on "evolution medicine" yesterday during the meeting of the American Association for the Advancement of Science.
"We want to understand why, and how, the body is susceptible to certain diseases," said Nesse. "The body is certainly not designed for its arteries to clog up at the age of 50 or 60."
Colicky babies who cry for hours may be entirely normal. It is the modern parenting habits of recent centuries that are often at fault, said Dr. Ronald Barr of the Department of Pediatrics at Montreal Children's Hospital.
Colic, he found, is virtually never a problem in today's few remaining hunter-gatherer societies, such as the Bushmen of Botswana, where mothers typically carry their infants almost constantly and feed them two to four times an hour for a few minutes at a time.
More study is needed to see if the tribe's babies are so content because of the way they are carried and fed, he said. But he is sure that many behaviors and habits seen is the Western world as indications of illness might, in the long evolutionary view, be entirely normal.
In a similar vein, anthropologist James McKenna of Pomona College said new studies of mothers and babies sleeping together revealed a complex tapestry of interactions as the two synchronize their cycles of different levels of sleep and touch, and communicate in other ways even during slumber.
In virtually all pre-industrial societies, he said, mothers sleep with their babies for many months. One possibility is that some instances of sudden infant death syndrome might be linked to the Western habit, developed only in recent centuries, of putting newborns in cribs, often in separate rooms from other people.
"Sleeping together may be the most evolutionarily normal" habit for mothers and infants, he said. Putting babies in their own beds may "encourage them to sleep too long and too hard too soon."
More evidence may come in breast cancer rates.
The disease may be 100 times more common in Western women than in pre-industrial societies, even after correcting for today's longer life spans, said Dr. S. Boyd Eaton, a radiologist and anthropologist at Emory University in Atlanta.
The reason, said Eaton, may be that the first women became pregnant much sooner after they reached puberty, had many more babies and nursed much more. As a result, certain key tissues in the breast do not multiply as much, and that lowers the risk of mutations that lead to cancer.
"Stone Age women spent much more of their time in a condition in which their breast cells are protected" from states that increase cancer risk, he said. The finding may give clues to medical researchers to find ways to mimic such conditions in women's breasts today without requiring them to be almost always pregnant or nursing. New formulations of birth control pills might do the job.
The idea of interpreting modern disease in an evolutionary context is not new. The meeting featured a luncheon address by Dr. Denis Parsons Burkitt, an 83-year-old British physician who worked for nearly 50 years in Africa.
Burkitt is among the world's most revered epidemiologists. He has maintained for years that nearly all the chronic diseases that fill Western hospitals are due to fatty, meat-laden, overly sweet diets low on the bulky, high-fiber, starchy and relatively lean and meat-free foods on which humanity survived until very recently.
Many Diseases Absent
In Africa, treating people who live largely off the land on vegetables they grow, Burkitt said, he hardly ever saw cases of many of the most common diseases in the United States and England including coronary heart disease, adult-onset diabetes, varicose veins, obesity, diverticulitis, appendicitis, gallstones, dental cavities, hemorrhoids, hiatal hernias and constipation.
Western diets are so low on bulk, he added, and so dense in calories, that our intestines just don't pass enough volume to remain healthy. Plunging right into the excretory behavior of the West, he said: "America is a constipated nation.... If you pass small stools, you have to have large hospitals."
Burkitt asserted that in 20 years of surgery in Africa, he had to remove exactly one gallstone. At an African medical school, students had a hard time learning about heart disease because they saw so few cases. Westerners' longer life spans are due to better sanitation and control of infectious diseases, not to better food.
"The only way we are going to reduce disease," he said, "is to go backward to the diets and lifestyles of our ancestors."