Triglycerides are involved in the transport of fatty acids to muscles and tissues for energy. HDL particles are involved in the transport of excess fatty acids from the periphery back to the liver for elimination. Because of these competing roles, it is very difficult to increase HDL, the healthy good cholesterol, without first addressing triglycerides. HDL not only transports excess lipid to the liver for disposal, it transports cholesterol to organs such as the adrenals, ovaries, and testes for steroid hormone synthesis. Many of the strategies discussed here that lower triglycerides are also known to raise HDL.
Triglyceride (abbreviated TG or TAG, for triacylglyceride) – is the storage form of fatty acids. Triglycerides are made of up three fatty acids linked to 3-carbon molecule called glycerol that acts as a sort of backbone. While triglycerides are stored in fat cells (called adipose cells or adipocytes), they also circulate in the bloodstream, and are easy to measure. Obviously elevated levels of stored triglycerides are harmful (., excess fat stored in fat cells), but so, too, are elevated levels of circulating (., in blood) triglycerides. In particular, when circulating triglycerides are made up of saturated fatty acids, there is evidence of harm. Contrary to what people think, eating saturated fat does not increase saturated fatty acid content in triglycerides. In fact, reduction in carbohydrate intake, coupled with increased saturated fat intake, actually lowers both circulating triglycerides and the amount of saturated fatty acid within triglycerides. Unfortunately, most doctors don’t realize this and they tell patients with elevated triglycerides to reduce fat intake. Ironically, this is the wrong treatment.
What we’re finding out is that exercise and fasting can raise LDL a lot in lean, healthy people. Whereas these same factors will tend to lower LDL (at least at first) in high-risk individuals. Recently Dave Feldman has shown that the more fat a lean, healthy person eats before a cholesterol test, the lower their LDL will be.
From this it seems that LDL cholesterol levels in the past have been based on populations of middling fitness, eating conventional diets, and correlations drawn from them may not be accurate at all for anyone outside this demographic, for example the low carb, crossfit generation. TG and HDL, meanwhile, continue to behave much as expected – sugar will increase TG and (eventually) lower HDL in anyone.