Among the most neglected yet enormously helpful values on any standard cholesterol panel is the triglyceride value.
Triglycerides traverse the bloodstream by hitching a ride on water (serum)-soluble lipoproteins, or lipid-carrying proteins. We measure triglycerides as an indirect index of triglyceride-containing lipoproteins.
Triglycerides are a basic currency of energy. While the average American ingests around 300 mg of cholesterol per day, he or she also ingests 60,000-120,000 mg (60-120 grams) of triglycerides, i.e., 200 to 400 times greater amounts, from fat intake. Zero triglycerides in the diet or in the bloodstream is not an option.
But what represents too much triglycerides in the bloodstream? There are several observations to help us make this determination:
1) When fasting triglycerides are 133 mg/dl or greater , 80% of people will show show at least some degree of small LDL particles.
2) When fasting triglycerides are 60 mg/dl or less , most (though not all, since genetic factors enter into the picture) people will show little to no small LDL particles.
3) When fasting triglycerides are 200 mg/dl or greater , small LDL particles will dominate and large LDL particles will be in the minority or be gone entirely.
4) When triglycerides are 88 mg/dl or greater after eating, then risk for heart attack is doubled. Non-fasting triglycerides in the 400+ mg/dl range are associated with 17-fold greater risk for heart attack.
From Austin et al 1990. "Phenotype A" means that large LDL particles dominate; "phenotype B" means that small LDL particles dominate.
Note that conventional "wisdom" (i.e., NCEP ATP-3 guidelines) is that triglycerides of up to 150 mg/dl are okay, a level that virtually guarantees expression of small LDL particles and increased cardiovascular risk.
Based on observations like these, in the Track Your Plaque program we aim for fasting triglycerides of no higher than 60 mg/dl and postprandial (after-meal) triglycerides of no more than 90 mg/dl.
Curiously, while fat intake (i.e., triglyceride intake) plays a role in determining postprandial triglyceride blood levels, it's carbohydrate intake that plays a much larger role. That will be an issue for another day.