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New World Syndrome - Page 2
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aul Zimmet, an Australian physician and researcher who specializes in the study of noncommunicable diseases, wrote in 1996 that "the [non-insulin-dependent diabetes mellitus] global epidemic is just the tip of a massive social problem now facing developing countries." Zimmet implicated the "coca-colonization" that has devastated local customs and economies and led to ill health. Rates of obesity and diabetes have skyrocketed around the globe, but particularly among traditional peoples in transition—Polynesians, Native Americans, and aboriginal Australians; Asian Indian emigrants to Fiji, South Africa, and Britain; and Chinese emigrants to Singapore, Taiwan, and Hong Kong.
Although the rapid introduction of processed foods and other conveniences is certainly the proximate force behind this trend, scientists are also looking at genetic components. Jeffrey Friedman, a professor and the head of the Laboratory of Molecular Genetics at the Howard Hughes Medical Institute at Rockefeller University, in New York, is investigating why some Kosraeans manage to escape the hazards of coca-colonization while others succumb. To Friedman and his team, the interesting question is not why so many sedentary, office-bound, Spam-loving Kosraeans are obese but why not all of them are.
Kosraeans, like all natives of Micronesia, trace their ancestry back 2,000 years to a handful of Indo-Malayan mariners. Driven by fear, religious persecution, greed, or foolhardiness, this small band settled the Pacific. Those who landed on Kosrae developed a feudal society that went largely unnoticed by the West until 1824, when a French research vessel, the Coquille, dropped anchor nearby. Rene Primevere Lesson, the ship's doctor, described Kosraeans as "advanced people of a high civilization, to judge from the vestiges of customs, tradition such as the authority of the chiefs, classes of society, and the remnants of the arts which they still practice." The women, he wrote, had "black eyes full of fire and a mouth full of superb teeth
but a tendency to become fat." He also observed that considering the island's bounty, its population of about 3,000 was surprisingly small. (Easter Island, in Polynesia, was then supporting a population of at least 7,000 with roughly the same land mass and a less hospitable climate.) Studies later supported local lore that a much larger population had been diminished by starvation after typhoons devastated the island's food supply. The population continued to dwindle throughout the nineteenth century, as Kosrae became an increasingly popular base for pirates and New England whalers, who brought with them tobacco and whisky—and infectious diseases. By 1910 only 300 Kosraeans had survived the Western imports of smallpox, measles, influenza, and sexually transmitted diseases.
James Neel, a geneticist at the University of Michigan Medical School who died last year, hypothesized in a 1962 article on diabetes that under conditions of scarcity natural selection weeds out people unable to store food efficiently in their bodies, and that a "thrifty genotype" encourages the conversion of calories into body fat. He suggested that this mechanism was necessary for survival during periods of extreme stress and famine that would otherwise ravage a population. Most populations are assumed to have some variation on this genotype, but it is likely that peoples whose evolution was punctuated by a number of particularly harrowing events developed the most-effective versions. In Kosrae, where weather and disease wiped out 90 percent of the population, this effect must have been profound. The very genes presumed to have protected islanders from their history are now believed to be predisposing them to life-threatening illnesses.
In 1994 Friedman and his team at Rockefeller cloned what is perhaps the ultimate thrifty gene—the obese gene, which in its normal form carries the chemical code for leptin. A hormone discovered by Friedman, leptin plays a critical role in the brain, regulating appetite and fat storage, among other things. Leptin is an extremely potent hormone. People who carry the abnormal form of the obese gene don't have the genetic makeup to produce leptin; they eat uncontrollably and are morbidly obese. Although very few people have this defect, all of us have variations along the leptin and perhaps other brain pathways that influence our eating habits and efficiency at turning calories into body fat. Friedman's group examined blood samples taken from 2,286 adult Kosraeans in the course of Auerbach's islandwide screening. Preliminary findings suggest that European genes inherited from New England whalers and other visitors protect Kosraeans to some degree against obesity and diabetes: the more "European" an islander, it appears, the less likely he or she is to be obese or diabetic. Zimmet says this finding is consistent with earlier findings linking Asian genes with those of populations from Native Americans to New Guinea highlanders. Scientists speculate that certain aspects of the Asian genotype, evolved in part to withstand long periods of scarcity, predispose hundreds of millions if not billions of people to obesity and diabetes.
Writing in Nature in 1992, Jared Diamond, a professor of physiology at the UCLA Medical School, suggested that the populations of Western industrial nations had already to some extent weeded out the thrifty genotype, keeping diabetes and obesity below the levels now common in Micronesia. "Before modern medicine made [diabetes] more manageable," he wrote, "genetically susceptible Europeans would have been gradually eliminated, bringing [diabetes] to its present [relatively] low frequency." Diamond and others have suggested that some human populations, notably those that evolved in regions of Europe, may have developed a relative resistance to certain noncommunicable diseases just as they did to some infectious diseases—through natural selection over centuries of relatively sustained plenty. Given the burgeoning rates of obesity and diabetes in the United States and other industrialized nations, this seems surprising, until one considers that rates among the most susceptible peoples—Pacific Islanders such as Native Hawaiians, Samoans, and Nauruans—are higher still. Indeed, all measures indicate that the greatest impact of obesity-related disorders will continue to be in newly industrialized and developing nations in Asia, Africa, the Caribbean, Latin America, and the Indian and Pacific Oceans which historically had an unstable food supply.
he World Health Organization recently described overeating as the "fastest growing form of malnourishment" in the world. For the first time in history the number of people worldwide who are both overweight and malnourished, estimated at 1.1 billion, equals the number who are underweight and malnourished. Obesity rates in China have quadrupled in the past decade, and obesity in the urban middle class in India is epidemic. In Colombia 41 percent of adults are overweight. The global spread of diet-linked disease presents one of the greatest medical challenges of the twenty-first century.
But when I spoke with agricultural and business leaders in Micronesia, it was clear that a concerted government effort to fight noncommunicable disease was not likely on these islands. I heard repeatedly that health was a matter of willpower and individual effort, and that government could do nothing to curb the public taste for imports. The fact that many state legislators in Micronesia are also food importers was never mentioned—nor were the particulars of auto importation in a tiny country already overrun with cars.
Father Francis Hezel, a Jesuit priest from Buffalo, New York, who has spent more than three decades teaching and writing in Micronesia, said that even people in power are reluctant to speak out. "You can enter any clinic and smell the decaying limbs, rotted by diabetes," he told me. "But many people here are beholden to the government. They don't want to rock the boat." In Micronesia—as in much of the world, particularly the developing world—it is more profitable for authorities to encourage overconsumption than to discourage it. The Worldwatch Institute reported last year that approximately four of the five McDonald's restaurants that opened every day in 1997 were outside the United States. In its 1998 annual report the Coca-Cola Company described Africa as "a land of opportunity."
Obesity, diabetes, and other manifestations of New World syndrome can, like infectious diseases, be contained. In Singapore the nationwide Trim and Fit Scheme, which began in 1992, has cut childhood obesity by up to 50 percent. And in Hawaii, Terry Shintani and colleagues at the Waianae Coast Comprehensive Health Center have shown long-term health benefits from a program emphasizing a return to traditional local foods.
We spotted a glimmer of progress in Micronesia, though not in the Western-style wellness programs. One of our hosts, a hospital administrator, told us that he neither farmed nor fished but did enjoy playing basketball, and that he would sometimes jog rather than drive to the high school gym to play. As a result of this regimen he had lost a significant amount of weight, and avoided some of the health problems suffered by his more sedentary compatriots. Basketball, he said, was catching on quickly in Kosrae, as was baseball. "Imports made us sick," he said. "Now maybe imports will help us get well."
However nice the thought, increasing amounts of junk food are being shipped into Kosrae from the West, food importers say, and the island is about to import television programming. Kosraeans will be able to come home, open a few cans of Spam, switch on the tube, and kick back for the evening. It is then that they will truly be able to live—and die—in the manner of their Western benefactors.
Copyright © 2001 by The Atlantic Monthly Group. All rights reserved.
The Atlantic Monthly; June 2001; New World Syndrome; Volume 287, No. 6; pp. 50-53.