Most people know it’s important to get their bad cholesterol (LDL) down to reduce their risk of heart attacks and strokes. Fewer people know that it’s also important to raise their good cholesterol (HDL) for the same reasons. Almost no one knows, however, that a low HDL likely puts them at a higher risk for heart attacks and strokes than does a high LDL. In other words, it’s more important to get your good cholesterol up than to get your bad cholesterol down.
In fact, though I can’t find the reference from which it was taken, I remember when I was a resident seeing a graph put up at a talk that showed the greatest risk for having a heart attack comes not from a high LDL, not from hypertension, diabetes, or even smoking, but rather from a low HDL. A recent study supports the notion that a low HDL contributes more to atherosclerosis (hardening of the arteries) than does a high LDL.
Why, then, do physicians focus most of their discussion and interventions on lowering their patients’ LDL and not raising their patients’ HDL? The reason is simple: we don’t have any drugs that have a significant effect on HDL. Exercise is known to raise HDL, but generally it must be of an intensity that in my own experience few patients are willing or able to maintain on a regular basis.
But recently, with the increasing popularity of low carbohydrate diets, a new, arguably less painful way to raise HDL—sometimes dramatically—has surfaced. It’s long been known that another component of total cholesterol—triglycerides—have an inverse relationship to HDL. That is, as triglycerides go up, in general, HDL goes down, and vice versa. And while dietary interventions have little direct effect on HDL, they can have a large direct effect on triglycerides. And when triglycerides go down, HDL often goes up.
How do you reduce your triglycerides? There seem to be two main ways: 1) weight reduction and 2) a reduction in dietary intake of carbohydrates. Especially in people who are overweight or obese, reducing the amount of carbohydrate in the diet (especially sweets—sorry) reduces triglycerides—and in so doing often raises HDL.
Though I only have anecdotal evidence of this effect currently, I have a lot of it—including evidence in myself. After learning that my triglycerides were 165 and my HDL 37 (40 is considered the point below which a low HDL puts you at higher-than-average risk for a heart attack), I went on a low carbohydrate diet, lost twenty pounds, and lowered my triglycerides to 41 and raised my HDL to 71. Given that we consider an HDL over 60 to actually be protective against heart attacks, this is an astounding result. And one in medicine we’ve traditionally viewed as impossible. As weight loss has been shown to have more of an effect on LDL, I strongly suspect the rise in my HDL was due mostly to the reduction in my triglycerides, which in turn was due mostly to my reducing the amount of carbohydrate in my diet (I’ve held the frequency and intensity at which I exercise constant since the first measurement of my cholesterol was taken).
The good news in all of this is that we can exert far more influence over our cardiac destiny that we previously thought. The bad news, of course, is that altering our diets isn’t easy. But for some, it’s easier than regular exercise. And if my experience—as well as the experience of a number of my patients—is to be believed, the power of lowering triglycerides to raise HDL may equal, if not outstrip, the power of intense exercise to do the same.
Next Week: Why I Don’t Drink