字幕表 動画を再生する 英語字幕をプリント "Cholesterol and Heart Disease: Why Has There Been So Much Controversy?" The scientific consensus is that lowering LDL cholesterol reduces heart attacks. So why are we still debating whether cholesterol-containing foods affect blood cholesterol? And how do eggs fit in? We look at those questions in this video and the next. "Cholesterol and Heart Disease: Why Has There Been So Much Controversy?" The cholesterol controversy is over. In fact you can argue it was over a century ago. It seemed obvious in 1920 that high cholesterol levels in the blood infiltrating your artery walls was the cause of coronary heart disease, the #1 killer of men and women, confirmed as unequivocally as the revelation that blood circulated throughout the body or that the tuberculosis bacteria causes tuberculosis. I've reviewed some of that evidence previously in videos like " How Do We Know That Cholesterol Causes Heart Disease?" and "Optimal Cholesterol Level." The question is why did it take so long? What is so puzzling is why we have to work so hard to sell the message given what seems to be an unbeatable amount of hard evidence. Many rejected the cholesterol- heart disease link because so many patients were dying of coronary heart disease despite so-called perfectly normal cholesterol levels. Of course as I've detailed before, having normal cholesterol levels in a society where it's normal to drop dead of a heart attack isn't exactly saying much. Ideally, we want to get our total cholesterol well under 150, since having high cholesterol levels in your blood is thought of as the only direct atherosclerotic risk factor. All the other things -- smoking, high blood pressure, diabetes, inactivity, obesity -- just exacerbate the damage caused by the high cholesterol. Another factor may be the preoccupation of cardiologists with all the new fancy gadgets and procedures out there. It's like we train them to be highly-skilled, high-tech fighter pilots to fight a war, but then sent them on some boring preventive diplomatic mission. But the reasons may be even more personal than that. As an editorial in the Journal of the American Heart Association asked nearly 50 years ago, why do we pretend the cause of heart disease is mysterious? There is no mystery as to why the incidence of heart disease, like that of lung disease and of venereal disease -- sexually-transmitted disease -- continues to rise for many decades after the cause is established. Why? Because human beings, including physicians, are eager for excuses, not to face annoying facts, and so they continue to do things which are agreeable but hazardous. People tend to reject new ideas, even when they don't impose any change in our way of life, and it's almost impossible for most men to accept any suggestion that it might be wise to give up agreeable habits such as smoking, unsafe sex, or eating their favorite foods. This continuing challenge is represented by a senior professor of medicine who questioned whether an alteration of diet would really affect the course of heart disease. These professors know the facts. The problem is that they, like so many patients, will not allow themselves to believe the message. Eating rich food just means too much to too many people, even when it's our gravest mortal threat. Scientific consensus panels going back decades established beyond a reasonable doubt that lowering LDL cholesterol reduces the risk of heart attacks. Consistent evidence unequivocally establishes that LDL causes our #1 killer, atherosclerotic cardiovascular disease. And what raises LDL cholesterol? Saturated fat. And where is cholesterol-raising saturated fat found? The #1 source is dairy, the #2 source is chicken, then pastries, pork, and burgers. And it's not just saturated fat. Dietary cholesterol has been known as a dominant factor in the genesis of atherosclerosis since 1908, which is why we should lower our intake of saturated fats, trans fats and dietary cholesterol as much as possible. This is consistent with how our biology evolved. Extensive evidence clearly indicates that a plant-based diet was the traditional eating pattern of our distant ancestors, and so dietary cholesterol intakes were typically very low, while at the same time we were packing in whole plant foods containing components like fiber to help us eliminate cholesterol. Where is dietary cholesterol coming from now? Overwhelmingly eggs, with the #2 source chicken, then beef, dairy, and pork. So wait a second. If the Institute of Medicine recommends that individuals consume as little dietary cholesterol as possible, presumably that would mean cutting out foods like eggs entirely. But does eating cholesterol actually raise your blood cholesterol? We'll find out next.