by Rob Dunn
Your dietary and medical choices alter this complex system, both the pieces of the system we know about and those we do not yet understand. Reduce consumption of saturated fats, and you can reduce levels of cholesterol in LDL in the blood. Increase the amount of cholesterol you have embedded in HDL, and you reduce your levels of cholesterol in LDL in the blood. Reduce your inflammatory response, and you can reduce how often your body attacks oxidized LDL. Or up your antioxidants, and you can reduce the chances that your LDL will get damaged in the first place. There are other processes involved too, other areas of the puzzle. Although it was not understood during the time the Keyses were working, when individuals eat too much simple sugar (glucose or fructose, particularly in the form of high-fructose corn syrup), that sugar is converted in the liver into triglycerides, which hitch a ride with LDL and HDL, so sugar consumption can affect cholesterol levels and dynamics. Also, the chance that a plaque, composed of dead immune cells, triglycerides, and LDL cholesterol, in an artery will rupture is influenced by blood pressure (which is influenced by stress, alcohol consumption, salt, smoking, and more), and the chance that ruptured plaques will lead to clogged coronary arteries is influenced by how likely your blood is to clog. Then there undoubtedly exists complexities we have not yet figured out or are only just learning of. As a result, just because a particular people’s diet is associated with heart health does not necessarily mean that one can simply switch to that diet and reap the full benefits of it; sugar consumption, inflammation, and genes also contribute to the health of the heart. Many bodily pieces are in play. There is more to being Italian than eating pasta and bread with olive oil.
Another problem was that the Keyses’ messages became oversimplified in the media and even in the medical community, so the lessons the public took from the Keyses’ inspiration were sometimes dangerously inaccurate. The most pernicious example of this oversimplification is the case of saturated fat. Ancel Keys railed against the intake of animal fats because of the links with blood cholesterol levels, atherosclerosis, and heart attacks. Animal fats came to be described as saturated fats, to differentiate them from the unsaturated fats in vegetable oils (which, throughout the Keyses’ work, showed the opposite effect on cholesterol, atherosclerosis, and heart attacks, a beneficial effect). To cater to the demand for unsaturated fats, the food industry began to create new sorts of fats that were both unsaturated and cheap. Fat molecules have long tails of carbon and hydrogen atoms. Different fat types differ in how the pieces of these tails are arranged. Fats with fewer hydrogen atoms are said to be unsaturated and are usually liquid at room temperature (for example, olive oil). Saturated fats have more hydrogen atoms and tend to be solid at room temperature (think of lard). The newer fats were trans fats, which are unsaturated fats (liquids) to which some hydrogen atoms have been added (making them partially hydrogenated and changing the structure of some of the molecules). The Center for Science in the Public Interest (CSPI) and the National Heart Savers Association (NHSA), informed in large part by the work of Keys, advocated for trans fats as replacements for saturated animal fats. Trans fats, after all, were not animal fats. The trans fats the CSPI recommended were primarily those in partially hydrogenated vegetable oil (typically soybean oil). Partial hydrogenation makes oils more solid and resistant to rot. It also, though the CSPI did not know it at the time, makes them more likely to contribute to the clogging of arteries (they simultaneously raise bad LDL and lower good HDL). For this reason, trans fats, which were created as a salvation, have recently been banned in more than a dozen U.S. jurisdictions and have been replaced in many thousands of food products. As I write, the U.S. Food and Drug Administration is taking steps toward a wholesale ban of these fats.
The Keyses can’t be held accountable for all the ways in which their work has been extended or misconstrued. But in one regard, they may have played a role in this process. The Keyses, Ancel Keys in particular, had an intuitive sense of marketing and of what people wanted. These were the skills that made the K ration successful. Ancel Keys was also capable of convincing people, including himself, of the greater good that could be achieved. This is what made men starve themselves for their country (but also for Ancel); it is also, in part, what convinced millions of people that they could, through conscious choice and scientific knowledge and reading the Keyses’ book, better their health and lives. To reach so many people, Keys knew that the food needed to be tasty and the message needed to be, if not quite simple, then at least simplified.
But the big problem with what Ancel and Margaret Keys suggested was the great divide between what individuals strive for and what they achieve. The Americans whom the Keyses implored to change their ways were not conscientious objectors or soldiers; they could not be forced to do what they were told, even if they were convinced it was good for them. The average American is far less able to control his or her diet than the conscientious objectors in Ancel Keys’s starvation study were. As a result, on average, Americans now weigh 50 percent more and have higher cholesterol (when untreated) than they did when the Keyses published their book. This is not because the diet the Keyses proposed made them fat and unhealthy. To the extent to which it has anything to do with the Keyses, it is because Americans followed up on those aspects of the Keyses’ diet that were easiest. They, as Keys instructed, avoided fat and tried to reduce calories. But to do so, they switched to carbohydrates and the cheapest calories, processed sugars (which themselves contribute to heart disease). In switching away from animal fats, they switched to the cheapest fats, partially hydrogenated oils (which are worse in terms of heart disease). Americans also, despite Keys’s instruction, ate more, and when one consumes more calories (particularly calories in the form of simple sugars) than one burns, one becomes, well, fatter. With this weight gain, a person is maybe more likely to have arteries filled with bad cholesterol but definitely more likely to suffer from one or more of the other maladies associated with obesity (or the awful combination of all of those disorders: metabolic syndrome).
The trajectory toward eating too much of all the wrong things has been a long time coming. One can compare the size of meals from long before the Keyses to the size of meals in the present. In the earliest paintings depicting the Last Supper, for example, the size of the meal was half what it was a couple of hundred years later, in Leonardo da Vinci’s version. The table in his Last Supper is, in turn, set with a meal considerably lower in calories than that in almost any modern painting involving food (and notably devoid of any meat except fish). The size of meals has risen in direct proportion to the availability of food. One expects that the composition has shifted too, in accordance with the cheapness and tastiness of foods. Two-thirds of Americans (and similar proportions of Brits, Australians, and so on) are now overweight or obese, with the proportion who are obese having doubled since the time of the Keyses’ book.
In other words, since learning ways to improve their diets from Keys, Americans have gotten less healthy, specifically in terms of heart disease, but also more generally. Many blame Keys for advocating the wrong diet in the first place. In today’s diet-book aisle, you can find books that argue that to lower your cholesterol or live more healthily, you should eat, variously, less red meat, more red meat, less sugar, fewer carbohydrates, raw foods, more completely cooked foods, food like our ancestors ate, or nothing but fruit.8 Yet all of these admonishments miss the point. Thousands of scientists since Ancel Keys have spent their lives studying how people can eat better. Many times more nutritionists have implored us to eat one or another of those well-researched diets. Yet we have, from one day to the next, progressively consumed foods that are worse and worse: foods with more calories; foods with fewer key nutrients; foods more likely to cause us to die, if not from heart disease, then from diabetes; foods no one argues are good.
A recent Spanish study makes this point clear.9 The study set out to examine the effects of versions of two Mediterranean diets—basically, simplified traditional Spanish diets—on
individuals who usually consumed high-calorie, carbohydrate-rich, nutrient-depleted diets with large doses of red meat. Spaniards’ diets have become so influenced by the global diet that the researchers could perform their study in Spain. In essence, they compared two diets like the kind Spaniards used to eat with the diet many Spaniards now eat. The scientists were able to convince participants to change their diets while going about the rest of their lives normally. They had one group of people, the control group, eat an average Western diet, essentially what they had been eating. They had another group of people eat a diet supplemented with olive oil, four tablespoons a day. Finally, they convinced a third group to consume extra olive oil, fatty fish, and tree nuts. The participants in this project were able to maintain these diets for two years. One can speculate that this is in part because the control diet was similar to one many people were already eating, and the experimental diets were tastier than the control diet. It must have also helped that high-quality fish, nuts, and olive oil were provided free by the study.
The study considered about seventy-five hundred people and focused on the effects of the different diets on heart disease and stroke. Overall, the study reported roughly 150 heart attacks, a similar number of strokes, and a similar number of deaths due to other heart-related problems. Amazingly, given the relatively short duration of the study and the modestness of the dietary intervention, it was found that individuals who consumed the control diet were at an increased risk of heart attacks, strokes, and heart-disease-related deaths relative to those consuming the olive oil–enriched diet and the nut and olive oil–enriched diet. Those consuming both nuts and olive oil were best off, particularly when it came to the risk of stroke.
One lesson that can be derived from this study is that versions of the Mediterranean diet really do seem pretty good for heart health, at least for Spaniards, with their genes, lifestyles, and microbes. Perhaps the same would hold if the experiment was repeated in the United States (though it might not, because of the many ways we differ from Spaniards in genes, lifestyles, and microbes). But the other lesson is that even people in Spain and Italy don’t eat Mediterranean diets anymore.
As for the fate of the Keyses, on some level, it seems, they knew things were more complex than they had described. As they began to age, they faced the same choices any of their readers might have in terms of deciding how to live. They could have adopted the diet they proposed, or tried to anyway, and lived the Mediterranean way in Minnesota. Instead, they decided to move to one of the places in their study that had the longest life expectancy (and winters far more forgiving than in Minnesota)—Southern Italy. There they lived into their nineties (before ultimately moving back to the United States for the last few years of their lives), partaking of a real Mediterranean diet and reaping the personal benefits of a career studying the best conditions for a long, balanced life.10
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The Beetle and the Cigarette
Diet, statins, angioplasty, and heart transplants are largely separate, unwoven threads in the story of the heart. But if you enter the hospital with chest pain and someone uses an angiogram invented by Forssmann and Sones to see your coronary arteries and discovers that one of those arteries is narrowed, hardened, and partially clogged, what is next? Which innovation or regimen is for you and will extend your life or even just improve its quality? For most of human history, what you did about chest pain was: nothing. You waited for the Russian roulette of your heart to play out. No one could have figured out that you had narrowed or blocked arteries, and even if someone had, he would have been able to do little more than lament your sorry fate.
Today, if you go to the hospital in the United States with chest pain and are found to have a very narrowed coronary artery, you will be given statins, told to “eat well” in the future, and then, depending on the severity of your heart disease, very likely be offered angioplasty and a stent. In the United States, more than half of patients who go to the hospital with the strangling sensation of angina and are diagnosed with coronary artery disease are given stents (typically simultaneously with drugs and dietary and lifestyle admonishments). More than a million stent surgeries were performed last year in the United States, one new stent for every two hundred and forty adults. It is both the most frequent and the most sophisticated solution. Along with the stent, a remarkable variety of additional procedures can be implemented inside your blood vessels. Your doctor can start with a stent and improvise based on what he or she finds. Work inside blood vessels has become some miraculous cross between Twenty Thousand Leagues Under the Sea and what the Roto-Rooter guy does to your clogged drainpipe.
Elsewhere in the world, the options are slightly different, or at least chosen in different proportions. In Canada, for instance, angioplasty and stents are far less common than in the United States. One explanation might be that perhaps stents really are the very best answer most of the time but Canadian medicine chooses cheaper and less effective alternatives. Yet we know that life expectancies in Canada and the United States are similar. Another possibility is that for some reason, in the United States we are choosing the very expensive solution where the cheap one might do.
The proof should be in the pudding—the fate of patients—but before we get to the pudding, let’s look at two scenarios. In one scenario, a patient comes into the hospital having actually suffered a heart attack. In this case, treatments are relatively similar in different regions and almost inevitably involve either a bypass or a stent. Far more common, though, is the scenario in which a patient comes in with angina and is found to have stable but severe atherosclerosis of the coronary arteries. In the latter case, a coronary artery might even be fully blocked, but if it is, blood is still finding its way through smaller, collateral coronary vessels, enough blood to keep the heart muscle working. A new series of studies provides as clear an answer as one could hope for, given the stumbling realities of science, medicine, and death, on what to do in this latter, stable situation. Before we turn to that study, let’s make clear the main options available to a doctor when a patient comes in with angina and a nearly clogged (or truly clogged) coronary artery. He or she could do a bypass. These are still done by the thousands but tend to be performed only in the most serious cases—when a patient is actually experiencing a heart attack—or for those patients who are at high risk for any of a variety of reasons (patients with diabetes and more than one clogged coronary artery are particularly likely to benefit from bypass surgery, as opposed to medical treatment or stents). Bypass surgeries require a heart surgeon, and heart surgeons are becoming less and less common at hospitals. The descendants of the great heart surgeons of the 1950s and 1960s now face tough competition from the cardiologists.1
The doctor could perform angioplasty and then place a stent. There are different types of stents, though doctors do not tend to choose the “best” stent. They choose their favorite. As a patient, you do not typically choose which stent; you just choose stent, and the doctor goes to get the one she or he always uses.
Finally, the doctor could simply employ a noninvasive medical treatment that relies on statins, beta blockers, aspirin, nitrates (such as nitroglycerin), calcium channel blockers, a prescription for exercise and dietary changes, and fate. Other options also exist; there are heart transplants, for example, but these are done rarely—only a few thousand a year—and considering their cost, they and other more invasive heart surgeries are reserved for when things get really bad, when the heart is failing or has failed. We’ll focus here on the most common alternatives.
Given these options, it seems important to understand how the outcomes for individuals with atherosclerosis and a bit of angina, that canary in the heart’s most dangerous mine shafts, compare among potential treatments. Again, American doctors tend to consider stents the best option. But the factors that go into the choice of a medical treatment by doctors are complex and influenced heavily, if not always consciously, by incentives, available technology, and the concepts of dise
ase doctors learn in medical school and that are inculcated into the culture of medical practice. We hope doctors spend extensive time reading scientific papers, learning the newest information, and following up on the fates of their patients. But many don’t have the chance; their jobs are stressful and busy, and they have less and less time for pondering, while the literature on potential treatments gets larger and larger. Historically, doctors were trained to be doers2 who learned through one anecdote or case study after another rather than via scientific evaluation of long-term results. A new generation of doctors is being pushed to weigh evidence and science. But the easiest place to learn about new science is still, as often as not, at big meetings, where those with the loudest, most sophisticated voices are not scientists but representatives of companies that design devices such as stents.
