Salt? Yes, it is the most-used condiment in our food and present in every kitchen. Yes, it helps make foods taste good. Yes, it has been used for thousands of years. And yes, the US Food and Drug Administration (FDA) deems it “generally recognized as safe.” So, you may wonder, why a whole book on salt? Why engage in salt wars when the public square is embattled with other controversies about diets high in calories, sugar, and fat, not to mention the political battles in Washington?
I confess that all through college and graduate school I had zero interest in nutrition—don’t ask about my diet then! I only got interested in what Americans were eating, who was producing those foods, and how the government monitored their safety when I moved in 1970 from Cambridge, Massachusetts, and MIT to Washington, DC, to volunteer with consumer advocate Ralph Nader. His organization had just published a book about the FDA, and he suggested that I write a book that would take a close look at food additives and how the FDA regulates them.
Frankly, I knew nothing back then about food additives, let alone how to write a book. But I dove into the project and came out with Eater’s Digest, in which I assessed the use and safety of more than a hundred additives. But—perhaps because familiarity can also breed disinterest—I said nothing about salt, even though I discussed in lavish detail the tiny amount of iodine added to it. Only a few years later, as my attention shifted from additives to nutrition, did I begin to learn about salt. And what I learned was deeply disturbing. Familiar as salt was to all of us, medical research had been discovering that consuming excess salt had serious, adverse health consequences. I ultimately concluded that salt is probably the single most harmful thing in our diet (perhaps with sugar a close second). Salt Wars follows naturally from the nearly 50 years of investigation into salt since the publication of my first book.
Salt has long been the focus of scientific and policy debates. But to put salt in context, let’s focus for a minute on two other substances in our food—sugar and fat—that have received much more attention than salt. For many years sugar was vilified for causing tooth decay, but it was not linked by strong research to deadly diseases. Yet in the past decade or so, sugar has been increasingly studied and increasingly controversial. New research found that sugar and its kissing cousin high-fructose corn syrup promotes obesity, diabetes, and heart disease. That led to demands by health activists around the country for soft-drink taxes and warning labels. The soft-drink industry adamantly denied that its products were anything but safe sources of water and pleasure, and it hired a fleet of lobbyists and PR firms to influence legislators and the public. The new evidence on sugar has led to an 18 percent decline in sugar consumption, as well as improved Nutrition Facts labels that disclose the amount of added sugars.
Sugar is easy for people to understand (and target) because it is such a predominant ingredient in foods: a can of soda pop has about 10 teaspoons of sugar, and a breakfast cereal aimed at kids might be more than one-third sugar. That gets people’s attention! In contrast, not many packaged foods have more than half a teaspoon of salt per serving.
Fatty foods and diets, too, have been perennially in the news. Countless stories have publicized the research on how polyunsaturated fatty acids (found mostly in vegetable oils) can reduce the risk of heart disease if they replace the saturated fatty acids (most abundant in meat, dairy products, and palm and coconut oils) in our diets. Other research has focused on whether fats contribute to obesity, a topic of great interest because two-thirds of Americans have overweight or obesity. Concerns about weight confront many of us every time we look in a mirror or step on a scale. In contrast, it is much easier to forget about the invisible signs of high blood pressure (hypertension) or heart disease caused by salty diets and other factors.
Trans fat, which generated a tsunami of attention beginning in the mid-1990s through the mid-2010s, was the perfect topic for journalists: it was a new threat, it was created in factories, it was a key ingredient in such iconic products as Crisco and Oreos—and most scientists and the FDA had considered it totally safe. The burst of reliable and unrebutted new research identifying trans fatty acids as a major cause of heart disease provided a practically open-and-shut case for action. In fact, the whole battle over trans fat was settled, by Washington standards, with astonishing speed. It took the FDA “only” 20 years to conclude that artificial trans fat was harmful and its source (partially hydrogenated vegetable oil, or PHO) was not “generally recognized as safe.” In June 2018, the FDA banned the use of PHOs in all foods sold and served in grocery stores and restaurants, although it granted some extensions of the compliance date.
So, partly obscured by the supernova controversies surrounding sugars and fats, the salt wars being fought by researchers, health officials, health advocates, and industry have been waged largely under the radar. Most scientists who have studied the health effects of salt—aka sodium chloride—long ago concluded that eating too much salt (or sodium) increases blood pressure, which in turn increases the risk of strokes and heart attacks. And eating too much is easy, considering the ubiquity of salt in the food supply and the number of restaurant meals that contain well over a day’s worth of sodium. Thus for many years, the American Heart Association, World Health Organization, and Centers for Disease Control and Prevention have urged food manufacturers and restaurants to sharply reduce sodium levels in their foods, which would automatically reduce sodium intakes by consumers.
But another group of researchers disagrees vehemently with the conventional wisdom. Their studies have indicated that Americans are eating a healthy amount of salt and that eating less would increase the risk of cardiovascular disease—a broad category that includes hypertension, coronary heart disease, heart failure, stroke, and other disorders. That was welcome news to food manufacturers and restaurants, which have long relied on salt as a cheap way to make and preserve delicious foods.
Medical journals were the initial battlefields of the salt wars, where opening shots were fired with the publication of controversial studies. Such studies have often elicited (and still do) fusillades of letters from opposing scientists. And that, in turn, spurred rebuttals from the original authors. Meanwhile, the usually restrained disagreements in journals turned into more spirited and candid arguments in newspapers and other popular media.
Quotable, outspoken warrior-professors have epitomized the two sides of the salt wars. For instance, Graham A. MacGregor, a British hypertension expert, is a leading advocate for consuming less sodium, whereas Michael Alderman, an American hypertension expert and former editor of the American Journal of Hypertension, argues that current sodium levels are not only safe but also virtually unchangeable. Call them the yin and yang of salt researchers: MacGregor has authored hundreds of published papers, is quick with a barb aimed at the food industry and recalcitrant health officials, ardently defends the establishment view on the causes of hypertension, and seeks to influence consumers, governments, and companies. Alderman, who also has published hundreds of scientific papers, has been quoted in the Wall Street Journal and the New York Times, and has been a leader of the rebels (several Canadian and Danish scientists are in this camp, too) whose research counters the view that people should eat less salt. Alderman, MacGregor, and their colleagues in academe have helped catalyze a very public debate over a mineral that makes up less than 1 percent of our diet.
One reason that the debate has been so vigorous is that most journalists treat new reports supporting the conventional view on salt with a yawn. Dog bites man? Big deal. What does capture the interest of journalists and headline writers are the man-bites-dog reports—those suggesting that eating less salt would be harmful—especially when they are conducted by credentialed researchers at prominent universities and published in respected journals. More-mainstream researchers criticize the reliability of such pro-salt research. But their efforts usually materialize too late, after journalists have already pounded away at their keyboards to author cleverly titled articles suggesting—or stating bluntly—that everything we have been told about salt is wrong. The poor consumer, lacking an advanced degree in epidemiology or nutrition, can get dizzy trying to follow the arcane biomedical and statistical jousting.
Industry—including the late, benighted Salt Institute, the salt industry’s PR and lobbying arm—then enlists studies that have found that cutting salt would be dangerous, and uses them to manufacture further doubt that high-sodium diets are as deadly as most experts say. Many companies do not want anyone mucking up their time-tested recipes (and profits), and so they contend that more research is needed before any conclusions are drawn or any government regulatory measures are deployed.
On the political battlefield in Washington, as in policy-making centers elsewhere in the world, industry and health advocates alike lobby their respective governments. They appear before Congress, or the FDA, or the White House to try to achieve their goals and to thwart their opponents’ efforts, as each side seeks to obtain or repeal a regulation, or win or block funding for a program, or set or prevent limits on sodium in foods. Most of those skirmishes come to naught, swallowed up by more immediate concerns, such as health insurance, or global warming, or the federal budget. But occasionally a measure sneaks through for better (such as in 1990 when Congress required the labeling of sodium and other nutrients on most packaged foods) or for worse (when the US Department of Agriculture in 2018 postponed or dropped tighter sodium limits in school foods).
The key questions that I explore in Salt Wars include: What is a safe amount of sodium to consume? Should everyone cut back on salt or only people with high blood pressure? Would cutting back save or cost thousands of lives a year? What should government and companies do, if anything? And what should we consumers do when we sit down for our next meal?
Here’s a chapter-by-chapter game plan for understanding the salt wars: I first describe how salt is used in food, how much we are consuming, and how much most nutrition experts say we should be consuming (chapter 1). In two key chapters, I investigate in some detail the health concerns connected to salt (chapter 2), focusing mostly on hypertension, heart attacks, and strokes, and move on to examine (in chapter 3) the contentions of the “sodium skeptics.” Happily for readers, though, I focus on only a tiny—but key—fraction of the Niagara of studies, review articles, and letters to medical journals on the topic. Next comes a concise evaluation and summary of the research on salt’s impact on cardiovascular disease (chapter 4). I follow that with revelations of the activities of the pugnacious Salt Institute (chapter 5), along with a brief discussion of the influence of money on scientists (chapter 6). I discuss what countries around the world, from Fiji to France, are doing to cut dietary salt (chapter 7), and recount the snail-like progress in the United States (chapter 8). There is good news to be had in chapter 9: the federal government, companies, and schools are finally beginning to address the salt problem. Continuing on a hopeful note, I present a plan for accelerating reductions of sodium in the food supply and in American diets (chapter 10), and discuss (in chapter 11) what you can do to protect your own and your family’s health without waiting for government or industry to do anything. (Many of these chapters include illustrations, tables, and information boxes to supplement or summarize the material I present; in the appendixes I list their titles, and include as well the abbreviations for key agencies, studies, and terms that appear throughout the book.) Finally, the epilogue puts salt in the context of other health disputes in which industry has played a decidedly unhealthy role.