Small LDL particles have skyrocketed to occupy number place as the most common cause for heart disease in the U.S.
Small LDL particles are different than large particles: Small LDL particles cling to the walls of arteries more than large; they hang around in the bloodstream up to 90% longer, allowing more time to take residence in your artery walls; they induce more oxidative and inflammatory reactions once in the artery. Of the 50+ studies performed examining whether small LDL particles are associated with coronary, carotid, or other vascular disease, all but a few have demonstrated a strong association.
Unfortunately, while most adults have had their basic cholesterol values checked, relatively few have had an assessment for small LDL particles. The blood test required to test for small LDL is no more difficult than the blood test for standard cholesterol. But it requires greater knowledge from your healthcare provider. Ah, that's the rub.
So, what common situations should raise your suspicion for having small LDL particles, the sort most closely linked to causing heart disease?
Here's a list:
High blood pressure - Over half of people with high blood pressure (usually defined in studies as 140/90 or greater) will have an abundance of small LDL particles.
Visceral obesity - People with a greater quantity of fat around the middle, often called "central" or "visceral" fat, nearly always have an abundance of small LDL particles. This is partly due to increased triglyceride levels in the blood stream, which triggers a series of reactions that create small LDL particles.
High triglycerides-In addition to visceral obesity, other causes of high triglycerides, such as excessive alcohol intake, genetically-determined high triglycerides, and low-fat diets (yes, low-fat diets), all contribute to creating small LDL particles.
High carbohydrate intake - Many Americans have been following conventional advice to reduce fat intake in their diet. The result: Increased carbohydrate intake. Carbohydrates in all forms, from candy to whole grain bread, trigger the formation of small LDL. This trend, in fact, has accounted for a virtual explosion in small LDL in Americans. In my view, advice to follow a low-fat diet has been among the most destructive dietary trends ever witnessed.
Low HDL cholesterol - The lower the HDL cholesterol level, the greater the proportion of small LDL particles will be. Most people will start to show small LDL particles at HDL of 60 mg/dl and below, with extravagant quantities when HDL is 40 mg/dl or less.
High blood sugar - High-carbohydrate diets go hand-in-hand with higher blood sugar levels, both fasting and/or after eating. Fats and proteins do not provoke blood sugar nor small LDL; carbohydrates trigger both. Thus, a diet weighed in favor of carbohydrates will inevitably trigger small LDL particles.
Small LDL is a common abnormality that frequently lurks behind "normal" cholesterol values, a heart disease risk factor that has become increasingly common as Americans indulge in processed carbohydrates and gain weight.
Three laboratory services provide lipoprotein testing in the U.S.: Liposcience (NMR) ; Berkeley Heart Lab (electropheresis or GGE) ; and Atherotech (ultracentrifugation) . Your doctor should be able to order these tests. However, be aware that not all physicians are even aware of this new method of assessing risk for heart disease, in which case you might consider asking to find out what physicians in your area provide these more sophisticated tests.
Next: An update on how to reduce small LDL