The World Until Yesterday: What Can We Learn from Traditional Societies? (72 page)

But that’s not to say that traditional New Guineans enjoyed a carefree health utopia: far from it. The lifespans of most of them were, and still are, shorter than in the West. The diseases that killed them, along with accidents and interpersonal violence, were ones that have by now been largely eliminated as causes of death in the First World: gastrointestinal infections producing diarrhea, respiratory infections, malaria, parasites, malnutrition, and secondary conditions preying on people weakened by those primary conditions. That is, we Westerners, despite having traded our set of traditional human illnesses for a new set of modern illnesses, enjoy on the average better health and longer lives.

Already in 1964, the new killers of First World citizens were beginning to make their appearance in New Guinea, among those populations that had had the longest contact with Europeans and had begun to adopt Western diets and lifestyles. Today, that Westernization of New Guinea diets, lifestyles, and health problems is in a phase of explosive growth. Tens of thousands, perhaps hundreds of thousands, of New Guineans now work as businesspeople, politicians, airline pilots, and computer programmers, obtain their food in supermarkets and restaurants, and get little exercise. In cities, towns, and Westernized environments one commonly sees overweight or obese New Guineans. One of the highest prevalences of diabetes in the world (estimated at 37%) is among the Wanigela people, who were the first New Guinea population to become extensively Westernized. Heart attacks are now reported among city-dwellers. Since 1998 I have been working in a New Guinea oil field whose employees eat all three daily meals in a buffet-style cafeteria where one helps oneself to
food, and where each dining table has a salt-shaker and sugar-shaker. New Guineans who grew up in traditional village lifestyles with limited and unpredictable food availability react to these predictable daily food bonanzas by piling their plates as high as possible at every meal, and inverting the salt and sugar dispensers over their steaks and salads. Hence the oil company hired trained New Guinean health workers to educate staff on the importance of healthy eating. But even some of those health workers soon develop Western health problems.

These changes that I have been watching unfold in New Guinea are just one example of the wave of epidemics of non-communicable diseases (NCDs) associated with the Western lifestyle and now sweeping the world. Such diseases differ from infectious (communicable) and parasitic diseases, which are caused by an infectious agent (such as a bacterium or virus) or a parasite, and which are transmitted (“communicate” themselves) from person to person through spread of the agent. Many infectious diseases develop quickly in a person after infection by the agent, such that within a few weeks the victim is either dead or recovering. In contrast, all of the major NCDs (as well as parasitic diseases and some infectious diseases, such as AIDS and malaria and tuberculosis) develop slowly and persist for years or decades until they either reach a fatal end or are cured or halted, or until the victim dies of something else first. Major NCDs in the current wave include various cardiovascular diseases (heart attacks, strokes, and peripheral vascular diseases), the common form of diabetes, some forms of kidney disease, and some cancers such as stomach, breast, and lung cancers. The vast majority of you readers of this book—e.g., almost 90% of all Europeans and Americans and Japanese—will die of one of these NCDs, while the majority of people in low-income countries die of communicable diseases.

All of these NCDs are rare or absent among small-scale societies with traditional lifestyles. While the existence of some of these diseases is attested already in ancient texts, they became common in the West only within recent centuries. Their association with the current explosive spread of the modern Western lifestyle around the world becomes obvious from their epidemics among four types of population. In the cases of some countries that became rich recently and suddenly, and most of whose in
habitants now “enjoy” the Western lifestyle—Saudi Arabia and the other Arab oil-producing nations, plus several suddenly affluent island nations including Nauru and Mauritius—the entire national population is at risk. (For instance, of the world’s eight countries with national diabetes prevalences above 15%, every one is either an Arab oil-producer or an affluent island nation.) Other epidemics are striking citizens of developing nations who emigrated to the First World, suddenly exchanged their formerly spartan lifestyle for a Western lifestyle, and are thereby developing NCD prevalences higher either than those of their countrymen who stayed home and continued their traditional lifestyle, or than those of long-term residents of their new host countries. (Examples include Chinese and Indians emigrating overseas [to Britain, the U.S., Mauritius, and other destinations more affluent than China or India], and Yemenite and Ethiopian Jews emigrating to Israel.) Urban epidemics are being recorded in many developing countries, such as Papua New Guinea, China, and numerous African nations, among people who migrate from rural areas to cities and thereby adopt a sedentary lifestyle and consume more store-bought food. Finally, still other epidemics involve specific non-European groups that have adopted a Western lifestyle without migrating, and that have thereby sadly become famous for some of the world’s highest prevalences of diabetes and other NCDs. Often-cited textbook examples include the Pima Indians of the U.S., New Guinea’s Wanigela people, and numerous groups of Aboriginal Australians.

These four sets of natural experiments illustrate how the adoption of a Western lifestyle, no matter what leads to it, by people previously with a traditional lifestyle results in NCD epidemics. What these natural experiments don’t tell us, without further analysis, is which particular component or components of the Western lifestyle trigger the epidemic. That lifestyle includes many components occurring together: low physical activity, high calorie intake, weight gain or obesity, smoking, high alcohol consumption, and high salt consumption. Diet composition usually shifts to low intake of fiber and high intakes of simple sugars (especially fructose), saturated fats, and trans-unsaturated fats. Most or all of these changes happen simultaneously when a population Westernizes, and that makes it difficult to identify the relative importance of individual ones of
these changes in causing an NCD epidemic. For a few diseases the evidence is clear: smoking is especially important as a cause of lung cancer, and salt intake is especially important as a cause of hypertension and stroke. But for the other diseases, including diabetes and several cardiovascular diseases, we still don’t know which of these co-occurring risk factors are most relevant.

Our understanding of this field has been stimulated especially by the pioneering work of S. Boyd Eaton, Melvin Konner, and Marjorie Shostak. Those authors assembled information on our “Paleolithic diet”—i.e., the diet and lifestyle of our hunter-gatherer ancestors and of modern surviving hunter-gatherers—and on the differences between the principal diseases affecting our ancestors and modern Westernized populations. They reasoned that our non-communicable diseases of civilization arise from a mismatch between our bodies’ genetic constitution, still largely adapted to our Paleolithic diet and lifestyle, and our current diet and lifestyle. They proposed tests of their hypothesis and offered recommendations about diet and lifestyle to reduce our exposure to our new diseases of civilization. References to their original articles and book will be found under the Further Readings for this chapter.

Non-communicable diseases associated with the Western lifestyle offer perhaps this book’s most immediately practical example of the lessons that can be extracted from traditional lifestyles. By and large, traditional people don’t develop the set of the NCDs that I’ve discussed, while by and large most Westernized people will die of these NCDs. Of course, I’m not suggesting that we adopt a traditional lifestyle wholesale, overthrow state governments, and resume killing each other, infanticide, religious wars, and periodic starvation. Instead, our goal is to identify and adopt those particular components of the traditional lifestyle that protect us against NCDs. While a full answer will have to wait for more research, it’s a safe bet that the answer will include traditional low salt intake and won’t include traditional lack of state government. Tens of millions of people around the world already consciously use our current understanding of risk factors in order to lead healthier lives. In the remainder of this chapter I shall discuss two NCD epidemics in more detail: the consequences of high salt intake and of diabetes.

While there are many different chemicals falling into the category termed “salts” by chemists, to laypeople “salt” means sodium chloride. That’s
the
salt that we crave, season our food with, consume too much of, and get sick from. Today, salt comes from a salt-shaker on every dining table and ultimately from a supermarket, is cheap, and is available in essentially unlimited quantities. Our bodies’ main problem with salt is to get rid of it, which we do copiously in our urine and in our sweat. The average daily salt consumption around the world is about 9 to 12 grams, with a range mostly between 6 and 20 grams (higher in Asia than elsewhere).

Traditionally, though, salt didn’t come from salt-shakers but had somehow to be extracted from the environment. Imagine what the world used to be like before salt-shakers became ubiquitous. Our main problem with salt then was to acquire it rather than to get rid of it. That’s because most plants contain very little sodium, yet animals require sodium at high concentrations in all their extracellular fluids. As a result, while carnivores readily obtain their needed sodium by eating herbivores full of extracellular sodium, herbivores themselves face problems in obtaining that sodium. That’s why the animals that you see coming to salt licks are deer and antelope, not lions and tigers. Human hunter-gatherers who consumed much meat, such as the Inuit and San, thus met their salt requirement readily, though even their total salt intake was only 1 or 2 grams per day because much of their prey’s sodium-rich blood and other extracellular fluids became lost in the course of butchering and cooking. Among traditional hunter-gatherers and farmers consuming a diet high in plant food and with limited meat, those living on the seacoast or near inland salt deposits also have easy access to salt. For instance, average daily salt consumption is around 10 grams among the Lau people of the Solomon Islands, who live on the coast and use salt water for cooking, and also among Iran’s Qashqa’i nomadic herders, whose homeland has natural salt deposits on the surface.

However, for dozens of other traditional hunter-gatherers and farmers
whose daily salt intake has been calculated, it falls below 3 grams. The lowest recorded value is for Brazil’s Yanomamo Indians, whose staple food is low-sodium bananas, and who excrete on the average only 50 milligrams of salt daily: about 1/200 of the salt excretion of the typical American. A single Big Mac hamburger analyzed by
Consumer Reports
contained 1.5 grams (1,500 milligrams) of salt, representing one month’s salt intake for a Yanomamo, while one can of chicken noodle soup (containing 2.8 grams of salt) represents nearly two months of Yanomamo salt consumption. A possible record was set by a Chinese-American restaurant near my home in Los Angeles. Its double pan-fried noodles combo dish was reportedly analyzed as containing one year and three days’ worth of Yanomamo salt intake: 18.4 grams.

Hence traditional peoples crave salt and go to great lengths to obtain it. (We, too, crave salt: just try eating nothing but fresh, unprocessed, unsalted food for one day, and then see how wonderful salt tastes when you finally sprinkle some on your food.) New Guinea Eastern Highlanders with whom I have worked, and whose diet consists up to 90% of low-sodium sweet potatoes, told me of the efforts to which they used to go to make salt a few decades ago, before Europeans brought it as trade goods. They gathered leaves of certain plant species, burned them, scraped up the ash, percolated water through it to dissolve the solids, and finally evaporated the water to obtain small amounts of bitter salt. The Dugum Dani people of the Western New Guinea Highlands made salt from the only two natural brine pools in their valley, by plunging a spongy piece of banana trunk into a pool to soak up brine, removing the piece and drying it in the sun, burning it to ash, and then sprinkling water on the ash and kneading the moist mass into cakes to be consumed or traded. After all that traditional effort to obtain small quantities of impure bitter-tasting salt, it’s no wonder that New Guineans eating in Western-style cafeterias can’t resist grabbing the salt-shaker on the dining table and letting the stream of pure salt run out onto their steaks and salads at every meal.

With the rise of state governments, salt became widely available and produced on an industrial scale (as it still is today) from salt-water drying pans, salt mines, or surface deposits. To its use as a seasoning was added its use, reportedly discovered in China around 5,000 years ago, to preserve food for storage over the winter. Salt cod and salt herring became fixtures of the European diet, and salt became the most traded and most taxed commodity in
the world. Roman soldiers were paid in salt, so that our word “salary” for pay is derived not from the Latin root for “money” or “coins” but from the Latin root for “salt” (
sal
). Wars were fought over salt; revolutions broke out over salt taxes; and Mahatma Gandhi rallied Indians against the perceived injustice of British colonial rule by walking for one month to the ocean, violating British laws by illegally making salt for himself on the beach from the freely available salt water, and refusing to pay the British salt tax.

As a result of the relatively recent adoption of a high-salt diet by our still largely traditional bodies adapted to a low-salt diet, high salt intake is a risk factor for almost all of our modern non-communicable diseases. Many of these damaging effects of salt are mediated by its role in raising blood pressure, which I’ll discuss below. High blood pressure (alias hypertension) is among the major risk factors for cardiovascular diseases in general, and for strokes, congestive heart disease, coronary artery disease, and myocardial infarcts in particular, as well as for Type-2 diabetes and kidney disease. Salt intake also has unhealthy effects independent of its role in raising blood pressure, by thickening and stiffening our arteries, increasing platelet aggregation, and increasing the mass of the heart’s left ventricle, all of which contribute to the risk of cardiovascular diseases. Still other effects of salt intake independent of blood pressure are on the risks of stroke and stomach cancer. Finally, salt intake contributes indirectly but significantly to obesity (in turn a further risk factor for many non-communicable diseases) by increasing our thirst, which many people satisfy in part by consuming sugary high-calorie soft drinks.