LDL and VLDL, and fructose

[JJR512]

I was just beginning some very basic research on lowering LDL and came across a statement, "Fructose, a component of sucrose as well as high-fructose corn syrup, upregulates hepatic VLDL synthesis." I can't tell if this is good or bad, but my suspicion is it's bad, based on some other things in the article. But I'm not sure if I'm understanding the other comments correctly or not. But I think if a person wants to lower their LDL, they should make an effort to lower their fructose consumption...correct?

 

[fma08]

Some fructose in your diet is a good thing. But like with the other sugars needed in your diet (glucose and galactose) too much leads to the problems. Excess intake, as already pointed out, will eventually lead to increased intermediates that are used in the production of triglycerides and eventually LDLs.

 

[JJR512]

The problem is that I don't understand the statement, "Fructose...upregulates hepatic VLDL synthesis." What does "upregulate" mean, does it mean fructose increases VLDL synthesis?

Since VLDLs are converted to LDLs in the bloodstream, one would want to minimize or moderate something that would increase VLDL production...correct?

 

[fma08]

Think of all of the biological processes as being on a rheostat, or like a dimmer switch. There is no "shutting off" of a process (under normal conditions), only up regulation (increasing the use of a pathway) or down regulation (decreasing the use of a pathway). So from your statement there, ingesting fructose will lead to increasing VLDL synthesis. I believe what happens, but don't quote me on this for sure, fructose is used and converted into products necessary for the Kreb's Cycle. If the body has enough energy and enough glycogen storage, then sugars (fructose included) that are taken in are processed into those intermediates, but then are used in the production of lipids since the carbohydrate storage is already "full" so to speak.

In regards to your question, you want to make sure you have a balanced diet, not like trying to lose weight diet, but are eating in the amounts a healthy person should. Fructose is needed in your diet, just don't over do it by chugging a case of Mt. Dew a day.