The “Bad Cholesterol” Problem ­– Updating the LDL Connection

     These clinical trials alone should put your mind to rest about the idea that eating high-fat or high-saturated-fat diets will give you heart disease. But there are a few other factors worth

discussing that most of these trials didn’t address. The first involves LDL. It speaks again to how the science of heart disease has evolved since the 1970s.

    When we first started hearing about the evils of LDL and physicians and health reporters began to refer to LDL as the “bad cholesterol,” they did so because they thought it was the cholesterol that caused the buildup of plaque in our arteries. LDL, though, actually isn’t cholesterol; it’s the particle (the low-density lipoprotein –i.e., LDL) that contains the cholesterol and shuttles it (and Triglycerides) around the bloodstream. The “bad cholesterol” terminology is a problem only because the researchers who study these things now say that it’s not the cholesterol carried by the LDL that is to blame for heart disease but, rather, the LDL particle itself and other similar particles. The cholesterol seems to be an innocent bystander.

     To complicate matters, not all LDL particles appears to be equally harmful, or “Atherogenic,” which is the term used by the experts to describe something that causes Atherosclerosis or makes it worse. Some of the LDL in our circulation is large andBuoyant, and some is small and dense, and there are gradations in between. The small and dense LDL particles appear to be the Atherogenic once, the one we want to avoid. They work themselves into the walls of our arteries and being the process of forming plaque. The large, buoyant LDL particles appear to be harmless.

    This is important because carbohydrate-rich diets not only lower HDL and raise

triglycerides; they also make LDL small and dense. These three effects all increase our risk of heart disease. When we eat high-fat diets and avoid carbohydrates, the opposite happens: HDL goes up, triglycerides go down, and the LDL in the circulation becomes larger and fluffier. Individually and together, these changes decrease our risk of having a heart attack. So what appears to be a bad thing, circa 1970 science (the effect of saturated fat on LDL cholesterol), is again a good thing, circa 2010 science (the effect of saturated fat on the LDL particle itself).

     The health officials hesitate to discuss this science publicly, because it contradicts much of what we’ve been told for the past thirty to fifty years. Occasionally, though, researchers will let the facts break through, as did Chris Gardner and his Stanford colleagues when they wrote up the results of their A TO Z study. Their language is on the technical side, but it’s not so technical that you shouldn’t be able to follow it:

      Two of the more consistent findings in recent trials of low-carbohydrate vs low-fat diets have been higher (LDL cholesterol) concentrations and lower triglyceride concentrations in the low-carbohydrate diets. Although a higher (LDL cholesterol) concentration would appear to be an adverse effect, this may not be the case under these study conditions. The triglyceride-lowering effect of a low-carbohydrate diet leads to an increase in LDL particle size, which is known to decrease atherogenicity. In the current study, at 2 months, mean (LDL cholesterol) concentrations decreased by 2% and mean triglyceride concentrations decrease by 30% in the Atkins group. These findings are consistent with a beneficial increase in LDL particle size, although LDL particle size was not assessed in our study.

    These findings may indeed be a bitter pill for some to swallow, but they confirm that the diet we have to eat to lose weight–the one restricted in fattening carbohydrates–is also the diet that will best prevent heart disease.

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