Heart disease continues to devastate the country, and, as you may have noticed, we certainly havent gotten any thinner. Ultimately, thats because fat should never have been our enemy. The big question is whether the 2010 Dietary Guidelines, due out at the end of the year, will finally announce retreat. The foundation for the fat is bad mantra comes from the following logic: Since saturated fat is known to increase blood levels of bad LDL cholesterol, and people with high LDL cholesterol are more likely to develop heart disease, saturated fat must increase heart disease risk. If A equals B and B equals C, then A must equal C. Well, no. With this extrapolation, scientists and policymakers made a grave miscalculation: They assumed that all LDL cholesterol is the same and that all of it is bad. A spate of recent research is now overturning this fallacy and raising major questions about the wisdom of avoiding fat, especially considering that the food Americans have been replacing fat with—processed carbohydrates—could be far worse for heart health. Last year, Ronald Krauss, director of atherosclerosis research at the Childrens Hospital Oakland Research Institute, teamed up with researchers in Sweden to tease out some of the more nuanced characteristics of LDL cholesterol and its role in heart health. The term LDL cholesterol refers to the cholesterol housed in low-density lipoprotein particles, and these particles come in a range of sizes. Krauss and his colleagues analyzed the LDL particles they found in blood samples taken a dozen years earlier from 4,600 Swedish men and women and discovered that concentrations of the small- and medium-sized LDL particles best predicted whether the subjects later developed heart disease. Larger LDL particles, they noted in their study, which was published in Arteriosclerosis, Thrombosis, and Vascular Biology,were essentially neutral with regard to the subjects heart health. This finding is particularly interesting in light of what Krauss had uncovered years earlier: Men who switch from a low-saturated-fat diet to one high in saturated fat experience an increase in total blood LDL cholesterol, as expected. But the change is mostly the result of a spike in the concentration of large LDL particles, not small. In other words, saturated fat consumption typically boosts the number of particles that Krauss has shown to be harmless. Blood tests for LDL cholesterol might not even be a dependable indicator of your risk of heart disease. Take, for instance, the infamous Womens Health Initiative hormone trials. Though women on hormone replacement therapy experienced overall drops in LDL cholesterol, they did not suffer fewer heart attacks. The finding initially baffled trial investigators, but further analysis revealed that the womens LDL particle concentrations had remained exactly the same. Recently, researchers including James Otvos, a biochemist at North Carolina State University, have reported that cholesterol tests—the kind most doctors administer—accurately predict heart disease risk only about 70 percent of the time, because they ignore particle size. (Otvos company, LipoScience, plans to start selling particle-based cholesterol tests to doctors offices later this year.) - slate.me/1rAk7Uw
Posted on: Sun, 28 Sep 2014 02:00:02 +0000
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