 On the standard American diet, atherosclerosis, hardening of the arteries, the number one killer of men and women starts in your teens. Investigators collected about 3,000 sets of coronary arteries and aorta, the main artery in the body, from accident, homicide, and suicide victims, 15 to 34 years of age. And this is what they found. The fatty streaks start in our teens, which turn into atherosclerotic plaques in our 20s, which get worse in our 30s, and can then start killing us off. In our heart, it can cause a heart attack. In our brain, it can cause a stroke. How common is this? 100% of the teens they looked at already had fatty streaks building up inside their arteries. And by their early 30s, most already had streaks blossoming into atherosclerotic plaques bulging into their arteries. This is what their aorta looked like at ages 15 through 19. Fatty streaks building up throughout, but no plaques yet on average. But the plaques start appearing in their early 20s and get worse in their late 20s, by which time fatty streaks have infiltrated throughout. And by our early 30s, our arteries are in bad shape. But that's our aorta, the main artery that plunges down through our torso to split off into our legs. What about the coronary arteries feeding our heart? Same thing. We start out with fatty streaks in our teens, begin to see the first hint of plaque in our early 20s, then late 20s, then look at the average coronary arteries of 30 to 34-year-olds. Most people in their early 30s already have plaques in their coronary arteries. Atherosclerosis begins in youth. So that's why we shouldn't wait until heart disease becomes symptomatic to treat it. If it starts in youth, we should start treating it in youth. It's like if you knew you had a cancerous tumor. You wouldn't want to wait until it grew to a certain size to treat it, or if you had diabetes. You wouldn't want to wait until you started going blind before you did something about it. OK, so how do you treat atherosclerosis? You lower LDL cholesterol through a stringent diet that is low in cholesterol and saturated fat. So a diet that's low in eggs, meat, dairy, and junk. If we want to stop this epidemic, we have to alter our lifestyle accordingly, starting as early as possible. Is such a radical proposal totally impractical? I mean, eating more healthfully? Radical. It would, of course, take an all-out commitment, but remember, this is our number one cause of death. I mean, if you're going to commit to anything, we did pretty good with cigarettes, slashing smoking rates, and lung cancer rates came right down. And yes, healthy eating is safe. According to the Academy of Nutrition and Dietetics, the largest and oldest association of nutrition professionals in the world, even strictly plant-based diets are appropriate for all stages of the lifestyle, from pregnancy, infancy, through old age. And if you want to learn more, the Academy can suggest a few good websites to visit. Curing atherosclerosis should be the next major cardiovascular prevention goal. What evidence do we have that a lifelong suppression of LDL will do it? There's a genetic mutation of a gene called PCSK9 that about 1 in 50 African-Americans are lucky to be born with, because it gives them about a 40% lower cholesterol their whole lives. And indeed, they have dramatically lower rates of coronary artery disease to show for an 88% drop in risk, despite otherwise terrible risk factors on average. Most had high blood pressure and were overweight, almost a third smoked, and nearly 20% had diabetes. But that just goes to show that a lifelong history of reduced LDL cholesterol levels significantly lowers the risk of coronary heart disease even in the presence of multiple risk factors. And this near 90% drop in events like heart attacks or sudden death occurred at an average LDL of 100 compared to 138. So you could get even lower than 100. Hold on. Why does the lowering of LDL cholesterol by about 40 points, and those with that lucky genetic mutation, reduce heart disease incidents by nearly 90%, whereas that same 40-point drop with statin drugs would reduce heart disease by only about 20%. The most likely answer is duration. When it comes to lowering LDL cholesterol, it's not only how low, but how long it's been low. That's why healthy lifestyle choices may wipe out like 90% of our risk for having a heart attack, whereas drugs may reduce it only by 20% to 30%. If you're getting treated with drugs later in life, you may have to get your LDL under 70 to halt the progression of coronary atherosclerosis. But if we start early enough, young enough, it may be sufficient to just lower LDL cholesterol down to 100, which should be attainable for most people. That's consistent with country-by-country data that suggests that heart disease would bottom out at a population average of about 100. But that's if you can keep it down your whole life. If you're just using drugs late in life to try to stop the progression of your disease, you have to get your LDL lower than 70. And if you're trying to use drugs to reverse a lifetime of bad food choices, you don't get to zero until about an LDL of 55. And if your heart disease is so bad you've already had a heart attack, while you're trying not to die from another one, ideally you might want to push your LDL down to about 30. Now, once you get that low, not only would you prevent any new atherosclerotic plaques, but you'd also help stabilize the plaques you already have, so they're less likely to burst open and kill you. Is it even safe to have cholesterol levels that low, though? In other words, can LDL cholesterol ever be too low? We'll find out next.