The Great Cholesterol Myth (27 page)

Cocoa flavanols now come in supplement form, so if you prefer not to eat a couple squares of dark chocolate a day, consider a supplement.

If you show this chapter to your doctor, and he or she is still skeptical, we suggest you direct him or her to the superb review paper on nonpharmacological treatment for dyslipidemia written by Mark Houston, M.D., and published in
Progress in Cardiovascular Diseases
.
⁵⁵
This paper has 421 citations and should go a long way toward reassuring him or her that there is plenty of research to support the use of these natural, non-toxic substances.

CHAPTER 8

IF YOU LIKE DETECTIVE STORIES, YOU’RE GOING TO LOVE THIS.

Back around 2000, a story came out about how the population of gray tree frogs in many American lakes was being decimated. The general consensus was that this was due to the use of a common pesticide, carbaryl (known by the brand name Sevin), which was found in large quantities in all of the lakes where frogs were dying. Carbaryl was clearly the villain, and environmentalists demanded that the company making carbaryl be held accountable.

A familiar story, right?

But here’s the thing: The manufacturers insisted that carbaryl wasn’t harming the frogs. They had a ton of studies showing that if you took the little creatures out of their lake homes, put them in a lab, and exposed them to the pesticide, nothing happened to them.

But the tree frogs were still dying. And the environmentalists were positive it had something to do with their continued exposure to this pesticide.

So who was right?

As it turns out, they both were. The studies were accurate. Self-serving though it might have been, the big, bad industrial manufacturer had good science showing that frogs were not being knocked off by its chemical. And the environmentalists had
equally
good science showing that carbaryl was the likely suspect in this massive decimation of gray tree frogs, frogs that managed to survive just fine, thank you very much, as long as there wasn’t any carbaryl around.

Enter Columbo in the form of Rick Relyea, Ph.D., a biochemical researcher from the University of Pittsburgh. Long story short, here’s what he discovered: The pesticide, carbaryl, was indeed pretty innocuous to frogs (meaning it didn’t kill them, at least) in the unnaturally tranquil setting of a lab. But most tree frogs don’t live in a lab; they live in the wild, where there are constant dangers from predators. When the frogs pick up a predator signal, when they literally “smell danger,” they secrete powerful stress hormones, just like our ancestors did when running from a wildebeest, or like we do when we’re caught in traffic or miss a deadline. Expose a
stressed
frog to the pesticide, and you’ve got a dead frog. Neither stress hormones nor pesticides alone were enough to kill the average tree frog, but the
combination
of the two—stress hormones and pesticides—was lethal.
¹

Subsequent studies over the next decade looked at the interaction between these two stressors—chemicals and predators—and examined how they interacted in a number of different organisms, including salamanders.
²
Several of the studies tested different pesticide chemicals with and without “predator cues” (signals that trigger the release of stress hormones), and every study confirmed that the combination of a pesticide and predator cues was far more lethal than any of the chemicals alone.

The take-home point, and the reason for this story, is that environmental elements
interact
with physiological elements in ways that can cause serious problems. (In the case of the gray tree frog, the interaction was a death sentence.) Although certain environmental and physiological elements might not be detrimental by
themselves
, when they’re combined they can sometimes spell big trouble.

And the element of our physiology that’s most likely to cause major problems for the health of the heart happens, not coincidentally, to be the subject of this chapter: stress.

Imagine, if you will, that you are a zebra grazing on the plains in the African Serengeti. Everything is peaceful, the grass is delicious, the sun is out, and all is well with the world. Suddenly you hear a faint rustling in the woods. You look up and see behind a bush the outline of a lion, a lion that is looking straight at you. You can almost see the thought bubble over its head: “Lunch!”

Your body switches into full alert, the equivalent of flipping to “red” in the Department of Homeland Security’s threat advisory system. The moment you see the lion, your hypothalamus, a section of the brain that acts as a kind of “first responder” in emergency situations, sends a hormonal signal to your pituitary gland. Instantly, the pituitary relays the message to the adrenal glands, two little walnut-shaped glands that sit on top of the kidneys. Their job is to pump out hormones whose actions are your only hope of living long enough to eat lunch tomorrow rather than becoming lunch today. These hormones—cortisol and adrenaline, specifically—are known as the stress hormones, and whether you’re a zebra running from a lion or a caveman running from a woolly mammoth, you have them to thank for your survival.

But these wonderfully adaptive, life-saving hormones have a dark side. They can, and do, contribute mightily to heart disease.

Let us explain.

Your stress hormones, also known as the “fight or flight” hormones, serve as a kind of turbocharger when you’re in a threatening situation. Without them, you’d be unable to react quickly enough to protect yourself from a predator or any other kind of danger. Cortisol and adrenaline, working together, and working far more quickly than you can read these words, prepare the body for action. Adrenaline, for example, immediately raises your heart rate and blood pressure as your heart begins to furiously pump blood through the vascular system in a mad rush to get it to the organs and muscles that need it most. Cortisol, the main stress hormone, causes sugar to be released into the bloodstream so that it can be delivered to the muscle cells and burned for energy, which happens to be particularly useful if you’re running for your life.

In response to these hormonal signals, the body diverts blood from wherever it’s not needed and directs it to where it is needed. (After all, if you’re running from a wild boar, it doesn’t make much sense for your body to send a ton of blood to your fingers, ears, reproductive organs, or digestive system.) The whole system is exquisitely designed to deliver just the right amount of nutrients, oxygen, and blood to the places where it’s most likely to contribute to your survival (the running muscles and the heart, for example).

This is the stress response in action. It’s meant to be quick, instant, and effective, its purpose singular: keeping you alive in a life-and-death situation. In the case of the zebra, it lasts only as long as it takes to get away from the lion, after which the zebra’s metabolism returns to normal, its heart rate slows down, and it goes back to grazing, blissfully forgetful that there was ever a problem in the first place.

This natural ability of animals to live in the moment as opposed to sitting around wondering whether there’s going to be another lion behind the next bush is what the great neurobiologist Robert Sapolsky was referring to when he titled his masterpiece on stress physiology
Why Zebras Don’t Get Ulcers
.

Sapolsky’s zebras experienced
acute
stress, which is ultimately temporary (unless of course the zebra is a slow runner, in which case the point is moot). Acute stress passes quickly, allowing us to return to “normal” and go about our business. The far more dangerous kind of stress, the kind that directly affects heart disease, is
chronic
stress. And that’s a whole different animal.

So here’s the big difference between the
acute
stress experienced by the zebra and the
chronic
stress that damages your heart. Acute stress is immediate and attention-grabbing. Your brain registers the threat of the marauding lion, and your stress response is instantly activated. It’s energetic, it’s explosive, and it’s wonderful—it’s what saves your life in an emergency. But if you turn it on too often, too long, or for psychological reasons—essentially the definition of chronic stress—you set yourself up for getting sick.

When stress persists, as it often does in people today, especially in those with certain personality and character traits, the abundance of cortisol from the adrenal cortex begins to promote hardening of the arteries. Hypervigilance, or being constantly on guard (that sense of waiting for the other shoe to drop), may also create an overabundance of cortisol, thus turning a
psychological
coronary risk factor into a
physical
one. With this kind of chronic stress, we can overdose on our own adrenal hormones, making
the heart vulnerable to unexpected cardiac events, such as heart attacks or arrhythmias. Remember that this damage doesn’t always occur immediately, but it will occur when the adrenal glands are pushed to the point of exhaustion. Overwork, prolonged stress, and exhaustion—all of which contribute to burnout—are harbingers of death by hormonal overdose. More on this in a moment.

The common notion that stress is just a psychological state—that it’s “all in your head”—is as outdated as the notion that cholesterol causes heart disease.

If we asked you right now to sit down and list the top ten things in your life that you find stressful, we bet that none of you would have the slightest problem coming up with a list. (In fact, the challenge would be limiting it to only ten items!) We further bet that your list would be front-loaded with psychological stressors—deadlines, traffic jams, sick kids, money, relationships—all of which take a constant toll, physically and psychologically.

But the common notion that stress is just a psychological state—that it’s “all in your head”—is as outdated as the notion that cholesterol causes heart disease. Stress has physical and physiological correlates. When you’re under stress, your body releases specific hormones that have specific actions and measurable results.

The stress response can save your life. It can also kill you.

Once upon a time, a country doctor was at a little tavern in Pennsylvania when in walked a doc from the “big city”; he was the head of medicine at the University of Oklahoma. The two physicians started talking shop over a couple of beers, and the local doc happened to casually mention a puzzling observation: Folks in his town were dying from heart disease at half the rate of the rest of the country.

Although this might sound like it’s the opening scene for some kind of reverse horror story—instead of being struck by some weird, alien disease, towns-people seem to be mysteriously protected from the very diseases that kill their neighbors!—it’s actually a true story. The meeting took place in the 1960s; the town was Roseto, Pennsylvania; and that chance meeting between two doctors at a local bar eventually led to an influx of medical researchers trying to understand the strange phenomenon, a phenomenon that ultimately became known as the “Roseto Effect.” (Google it. Go on. We’ll wait.)

In defiance of all logic, the residents of Roseto seemed to be eerily protected against heart disease. In Roseto the rate of death from heart disease was next to
zero
for men between the ages of fifty-five and sixty-four, not exactly an age group known to be immune to heart attacks. Men over the age of sixty-five did occasionally die from heart disease, but at a rate of about half the national average.

Okay, what could have been going on here? Tell the average American about the Roseto Effect, and he or she will probably say that the people of Roseto must have been living really healthy lives, going to the gym, eating low-fat diets, staying away from cholesterol, going easy on the salt, not eating red meat, and all that good stuff, right? That’s got to be the answer.

Well, not exactly.

Roseto, Pennsylvania, was, to put it gently, a hardscrabble town. Life was anything but easy. The men spent their days doing backbreaking, hazardous labor in underground slate mines. Their traditional Italian food was Americanized in the worst possible ways. They fried everything in lard. Most, if not all, of the men smoked. If there was a contest for “most likely to die of heart disease,” the men of Roseto could have won hands down.